112 files changed, 1132 insertions, 461 deletions

diff --git a/Documentation/RelNotes/2.29.0.txt b/Documentation/RelNotes/2.29.0.txt
index 483ebb4f8d..783cba3af5 100644
--- a/Documentation/RelNotes/2.29.0.txt
+++ b/Documentation/RelNotes/2.29.0.txt
@@ -19,6 +19,20 @@ UI, Workflows & Features
    configurable to selectively allow or reject object filtering
    specification used for partial cloning.
 
+ * Stop when "sendmail.*" configuration variables are defined, which
+   could be a mistaken attempt to define "sendemail.*" variables.
+
+ * The existing backends for "git mergetool" based on variants of vim
+   have been refactored and then support for "nvim" has been added.
+
+ * "git bisect" learns the "--first-parent" option to find the first
+   breakage along the first-parent chain.
+
+ * "git log --first-parent -p" showed patches only for single-parent
+   commits on the first-parent chain; the "--first-parent" option has
+   been made to imply "-m".  Use "--no-diff-merges" to restore the
+   previous behaviour to omit patches for merge commits.
+
 
 Performance, Internal Implementation, Development Support etc.
 
@@ -60,6 +74,14 @@ Performance, Internal Implementation, Development Support etc.
    easier to mark object existence checks that do and don't want to
    trigger lazy fetches, and a few such checks are converted using it.
 
+ * A no-op replacement function implemented as a C preprocessor macro
+   does not perform as good a job as one implemented as a "static
+   inline" function in catching errors in parameters; replace the
+   former with the latter in <git-compat-util.h> header.
+
+ * Test framework update.
+   (merge d572f52a64 es/test-cmp-typocatcher later to maint).
+
 
 Fixes since v2.28
 -----------------
@@ -110,6 +132,19 @@ Fixes since v2.28
    it is.
    (merge 11bc12ae1e rp/blame-first-parent-doc later to maint).
 
+ * The logic to find the ref transaction hook script attempted to
+   cache the path to the found hook without realizing that it needed
+   to keep a copied value, as the API it used returned a transitory
+   buffer space.  This has been corrected.
+   (merge 09b2aa30c9 ps/ref-transaction-hook later to maint).
+
+ * Recent versions of "git diff-files" shows a diff between the index
+   and the working tree for "intent-to-add" paths as a "new file"
+   patch; "git apply --cached" should be able to take "git diff-files"
+   and should act as an equivalent to "git add" for the path, but the
+   command failed to do so for such a path.
+   (merge 4c025c667e rp/apply-cached-with-i-t-a later to maint).
+
  * Other code cleanup, docfix, build fix, etc.
    (merge 84544f2ea3 sk/typofixes later to maint).
    (merge b17f411ab5 ar/help-guides-doc later to maint).
@@ -124,3 +159,4 @@ Fixes since v2.28
    (merge de20baf2c9 ny/notes-doc-sample-update later to maint).
    (merge f649aaaf82 so/rev-parser-errormessage-fix later to maint).
    (merge 6103d58b7f bc/sha-256-cvs-svn-updates later to maint).
+   (merge ac900fddb7 ma/stop-progress-null-fix later to maint).
diff --git a/Documentation/config/sendemail.txt b/Documentation/config/sendemail.txt
index 0006faf800..cbc5af42fd 100644
--- a/Documentation/config/sendemail.txt
+++ b/Documentation/config/sendemail.txt
@@ -61,3 +61,8 @@ sendemail.smtpBatchSize::
 sendemail.smtpReloginDelay::
 	Seconds wait before reconnecting to smtp server.
 	See also the `--relogin-delay` option of linkgit:git-send-email[1].
+
+sendemail.forbidSendmailVariables::
+	To avoid common misconfiguration mistakes, linkgit:git-send-email[1]
+	will abort with a warning if any configuration options for "sendmail"
+	exist. Set this variable to bypass the check.
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 7987d72b02..b7af973d9c 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -73,6 +73,11 @@ ifndef::git-format-patch[]
 	Synonym for `-p --raw`.
 endif::git-format-patch[]
 
+ifdef::git-log[]
+-t::
+	Show the tree objects in the diff output.
+endif::git-log[]
+
 --indent-heuristic::
 	Enable the heuristic that shifts diff hunk boundaries to make patches
 	easier to read. This is the default.
diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index 6e2a160a47..ff70625694 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -186,7 +186,7 @@ ifndef::git-pull[]
 endif::git-pull[]
 
 --set-upstream::
-	If the remote is fetched successfully, pull and add upstream
+	If the remote is fetched successfully, add upstream
 	(tracking) reference, used by argument-less
 	linkgit:git-pull[1] and other commands. For more information,
 	see `branch.<name>.merge` and `branch.<name>.remote` in
diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt
index 7586c5a843..0e993e4587 100644
--- a/Documentation/git-bisect.txt
+++ b/Documentation/git-bisect.txt
@@ -17,7 +17,7 @@ The command takes various subcommands, and different options depending
 on the subcommand:
 
  git bisect start [--term-{old,good}=<term> --term-{new,bad}=<term>]
-		  [--no-checkout] [<bad> [<good>...]] [--] [<paths>...]
+		  [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]
  git bisect (bad|new|<term-new>) [<rev>]
  git bisect (good|old|<term-old>) [<rev>...]
  git bisect terms [--term-good | --term-bad]
@@ -365,6 +365,17 @@ does not require a checked out tree.
 +
 If the repository is bare, `--no-checkout` is assumed.
 
+--first-parent::
++
+Follow only the first parent commit upon seeing a merge commit.
++
+In detecting regressions introduced through the merging of a branch, the merge
+commit will be identified as introduction of the bug and its ancestors will be
+ignored.
++
+This option is particularly useful in avoiding false positives when a merged
+branch contained broken or non-buildable commits, but the merge itself was OK.
+
 EXAMPLES
 --------
 
diff --git a/Documentation/git-log.txt b/Documentation/git-log.txt
index 3fd26d5212..2b8ac5ff88 100644
--- a/Documentation/git-log.txt
+++ b/Documentation/git-log.txt
@@ -114,8 +114,51 @@ include::rev-list-options.txt[]
 
 include::pretty-formats.txt[]
 
-COMMON DIFF OPTIONS
--------------------
+DIFF FORMATTING
+---------------
+
+By default, `git log` does not generate any diff output. The options
+below can be used to show the changes made by each commit.
+
+Note that unless one of `-c`, `--cc`, or `-m` is given, merge commits
+will never show a diff, even if a diff format like `--patch` is
+selected, nor will they match search options like `-S`. The exception is
+when `--first-parent` is in use, in which merges are treated like normal
+single-parent commits (this can be overridden by providing a
+combined-diff option or with `--no-diff-merges`).
+
+-c::
+	With this option, diff output for a merge commit
+	shows the differences from each of the parents to the merge result
+	simultaneously instead of showing pairwise diff between a parent
+	and the result one at a time. Furthermore, it lists only files
+	which were modified from all parents.
+
+--cc::
+	This flag implies the `-c` option and further compresses the
+	patch output by omitting uninteresting hunks whose contents in
+	the parents have only two variants and the merge result picks
+	one of them without modification.
+
+--combined-all-paths::
+	This flag causes combined diffs (used for merge commits) to
+	list the name of the file from all parents.  It thus only has
+	effect when -c or --cc are specified, and is likely only
+	useful if filename changes are detected (i.e. when either
+	rename or copy detection have been requested).
+
+-m::
+	This flag makes the merge commits show the full diff like
+	regular commits; for each merge parent, a separate log entry
+	and diff is generated. An exception is that only diff against
+	the first parent is shown when `--first-parent` option is given;
+	in that case, the output represents the changes the merge
+	brought _into_ the then-current branch.
+
+--diff-merges=off::
+--no-diff-merges::
+	Disable output of diffs for merge commits (default). Useful to
+	override `-m`, `-c`, or `--cc`.
 
 :git-log: 1
 include::diff-options.txt[]
diff --git a/Documentation/git-update-ref.txt b/Documentation/git-update-ref.txt
index 3e737c2360..d401234b03 100644
--- a/Documentation/git-update-ref.txt
+++ b/Documentation/git-update-ref.txt
@@ -148,12 +148,13 @@ still see a subset of the modifications.
 
 LOGGING UPDATES
 ---------------
-If config parameter "core.logAllRefUpdates" is true and the ref is one under
-"refs/heads/", "refs/remotes/", "refs/notes/", or the symbolic ref HEAD; or
-the file "$GIT_DIR/logs/<ref>" exists then `git update-ref` will append
-a line to the log file "$GIT_DIR/logs/<ref>" (dereferencing all
-symbolic refs before creating the log name) describing the change
-in ref value.  Log lines are formatted as:
+If config parameter "core.logAllRefUpdates" is true and the ref is one
+under "refs/heads/", "refs/remotes/", "refs/notes/", or a pseudoref
+like HEAD or ORIG_HEAD; or the file "$GIT_DIR/logs/<ref>" exists then
+`git update-ref` will append a line to the log file
+"$GIT_DIR/logs/<ref>" (dereferencing all symbolic refs before creating
+the log name) describing the change in ref value.  Log lines are
+formatted as:
 
     oldsha1 SP newsha1 SP committer LF
 
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index b01b2b6773..002379056a 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -128,8 +128,7 @@ parents) and `--max-parents=-1` (negative numbers denote no upper limit).
 	because merges into a topic branch tend to be only about
 	adjusting to updated upstream from time to time, and
 	this option allows you to ignore the individual commits
-	brought in to your history by such a merge. Cannot be
-	combined with --bisect.
+	brought in to your history by such a merge.
 
 --not::
 	Reverses the meaning of the '{caret}' prefix (or lack thereof)
@@ -207,7 +206,7 @@ ifndef::git-rev-list[]
 	Pretend as if the bad bisection ref `refs/bisect/bad`
 	was listed and as if it was followed by `--not` and the good
 	bisection refs `refs/bisect/good-*` on the command
-	line. Cannot be combined with --first-parent.
+	line.
 endif::git-rev-list[]
 
 --stdin::
@@ -743,7 +742,7 @@ outputs 'midpoint', the output of the two commands
 would be of roughly the same length.  Finding the change which
 introduces a regression is thus reduced to a binary search: repeatedly
 generate and test new 'midpoint's until the commit chain is of length
-one. Cannot be combined with --first-parent.
+one.
 
 --bisect-vars::
 	This calculates the same as `--bisect`, except that refs in
@@ -1117,48 +1116,3 @@ ifdef::git-rev-list[]
 	by a tab.
 endif::git-rev-list[]
 endif::git-shortlog[]
-
-ifndef::git-shortlog[]
-ifndef::git-rev-list[]
-Diff Formatting
-~~~~~~~~~~~~~~~
-
-Listed below are options that control the formatting of diff output.
-Some of them are specific to linkgit:git-rev-list[1], however other diff
-options may be given. See linkgit:git-diff-files[1] for more options.
-
--c::
-	With this option, diff output for a merge commit
-	shows the differences from each of the parents to the merge result
-	simultaneously instead of showing pairwise diff between a parent
-	and the result one at a time. Furthermore, it lists only files
-	which were modified from all parents.
-
---cc::
-	This flag implies the `-c` option and further compresses the
-	patch output by omitting uninteresting hunks whose contents in
-	the parents have only two variants and the merge result picks
-	one of them without modification.
-
---combined-all-paths::
-	This flag causes combined diffs (used for merge commits) to
-	list the name of the file from all parents.  It thus only has
-	effect when -c or --cc are specified, and is likely only
-	useful if filename changes are detected (i.e. when either
-	rename or copy detection have been requested).
-
--m::
-	This flag makes the merge commits show the full diff like
-	regular commits; for each merge parent, a separate log entry
-	and diff is generated. An exception is that only diff against
-	the first parent is shown when `--first-parent` option is given;
-	in that case, the output represents the changes the merge
-	brought _into_ the then-current branch.
-
--r::
-	Show recursive diffs.
-
--t::
-	Show the tree objects in the diff output. This implies `-r`.
-endif::git-rev-list[]
-endif::git-shortlog[]
diff --git a/Documentation/technical/commit-graph.txt b/Documentation/technical/commit-graph.txt
index 808fa30b99..f14a7659aa 100644
--- a/Documentation/technical/commit-graph.txt
+++ b/Documentation/technical/commit-graph.txt
@@ -210,12 +210,12 @@ file.
 			    +---------------------+
 			    |                     |
  +-----------------------+  +---------------------+
- |  graph-{hash2} |->|                     |
+ |  graph-{hash2}        |->|                     |
  +-----------------------+  +---------------------+
 	  |                 |                     |
  +-----------------------+  +---------------------+
  |                       |  |                     |
- |  graph-{hash1} |->|                     |
+ |  graph-{hash1}        |->|                     |
  |                       |  |                     |
  +-----------------------+  +---------------------+
 	  |                  tmp_graphXXX
@@ -223,7 +223,7 @@ file.
  |                       |
  |                       |
  |                       |
- |  graph-{hash0} |
+ |  graph-{hash0}        |
  |                       |
  |                       |
  |                       |
diff --git a/Documentation/technical/hash-function-transition.txt b/Documentation/technical/hash-function-transition.txt
index 5b2db3be1e..6fd20ebbc2 100644
--- a/Documentation/technical/hash-function-transition.txt
+++ b/Documentation/technical/hash-function-transition.txt
@@ -650,7 +650,6 @@ Some initial steps can be implemented independently of one another:
 
 The first user-visible change is the introduction of the objectFormat
 extension (without compatObjectFormat). This requires:
-- implementing the loose-object-idx
 - teaching fsck about this mode of operation
 - using the hash function API (vtable) when computing object names
 - signing objects and verifying signatures
@@ -658,6 +657,7 @@ extension (without compatObjectFormat). This requires:
   repository
 
 Next comes introduction of compatObjectFormat:
+- implementing the loose-object-idx
 - translating object names between object formats
 - translating object content between object formats
 - generating and verifying signatures in the compat format
diff --git a/Documentation/technical/http-protocol.txt b/Documentation/technical/http-protocol.txt
index 51a79e63de..96d89ea9b2 100644
--- a/Documentation/technical/http-protocol.txt
+++ b/Documentation/technical/http-protocol.txt
@@ -401,8 +401,9 @@ at all in the request stream:
 The stream is terminated by a pkt-line flush (`0000`).
 
 A single "want" or "have" command MUST have one hex formatted
-SHA-1 as its value.  Multiple SHA-1s MUST be sent by sending
-multiple commands.
+object name as its value.  Multiple object names MUST be sent by sending
+multiple commands. Object names MUST be given using the object format
+negotiated through the `object-format` capability (default SHA-1).
 
 The `have` list is created by popping the first 32 commits
 from `c_pending`.  Less can be supplied if `c_pending` empties.
diff --git a/Documentation/technical/index-format.txt b/Documentation/technical/index-format.txt
index faa25c5c52..f9a3644711 100644
--- a/Documentation/technical/index-format.txt
+++ b/Documentation/technical/index-format.txt
@@ -3,8 +3,11 @@ Git index format
 
 == The Git index file has the following format
 
-  All binary numbers are in network byte order. Version 2 is described
-  here unless stated otherwise.
+  All binary numbers are in network byte order.
+  In a repository using the traditional SHA-1, checksums and object IDs
+  (object names) mentioned below are all computed using SHA-1.  Similarly,
+  in SHA-256 repositories, these values are computed using SHA-256.
+  Version 2 is described here unless stated otherwise.
 
    - A 12-byte header consisting of
 
@@ -32,8 +35,7 @@ Git index format
 
      Extension data
 
-   - 160-bit SHA-1 over the content of the index file before this
-     checksum.
+   - Hash checksum over the content of the index file before this checksum.
 
 == Index entry
 
@@ -80,7 +82,7 @@ Git index format
   32-bit file size
     This is the on-disk size from stat(2), truncated to 32-bit.
 
-  160-bit SHA-1 for the represented object
+  Object name for the represented object
 
   A 16-bit 'flags' field split into (high to low bits)
 
@@ -160,8 +162,8 @@ Git index format
 
   - A newline (ASCII 10); and
 
-  - 160-bit object name for the object that would result from writing
-    this span of index as a tree.
+  - Object name for the object that would result from writing this span
+    of index as a tree.
 
   An entry can be in an invalidated state and is represented by having
   a negative number in the entry_count field. In this case, there is no
@@ -198,7 +200,7 @@ Git index format
     stage 1 to 3 (a missing stage is represented by "0" in this field);
     and
 
-  - At most three 160-bit object names of the entry in stages from 1 to 3
+  - At most three object names of the entry in stages from 1 to 3
     (nothing is written for a missing stage).
 
 === Split index
@@ -211,8 +213,8 @@ Git index format
 
   The extension consists of:
 
-  - 160-bit SHA-1 of the shared index file. The shared index file path
-    is $GIT_DIR/sharedindex.<SHA-1>. If all 160 bits are zero, the
+  - Hash of the shared index file. The shared index file path
+    is $GIT_DIR/sharedindex.<hash>. If all bits are zero, the
     index does not require a shared index file.
 
   - An ewah-encoded delete bitmap, each bit represents an entry in the
@@ -253,10 +255,10 @@ Git index format
 
   - 32-bit dir_flags (see struct dir_struct)
 
-  - 160-bit SHA-1 of $GIT_DIR/info/exclude. Null SHA-1 means the file
+  - Hash of $GIT_DIR/info/exclude. A null hash means the file
     does not exist.
 
-  - 160-bit SHA-1 of core.excludesfile. Null SHA-1 means the file does
+  - Hash of core.excludesfile. A null hash means the file does
     not exist.
 
   - NUL-terminated string of per-dir exclude file name. This usually
@@ -285,13 +287,13 @@ The remaining data of each directory block is grouped by type:
   - An ewah bitmap, the n-th bit records "check-only" bit of
     read_directory_recursive() for the n-th directory.
 
-  - An ewah bitmap, the n-th bit indicates whether SHA-1 and stat data
+  - An ewah bitmap, the n-th bit indicates whether hash and stat data
     is valid for the n-th directory and exists in the next data.
 
   - An array of stat data. The n-th data corresponds with the n-th
     "one" bit in the previous ewah bitmap.
 
-  - An array of SHA-1. The n-th SHA-1 corresponds with the n-th "one" bit
+  - An array of hashes. The n-th hash corresponds with the n-th "one" bit
     in the previous ewah bitmap.
 
   - One NUL.
@@ -330,12 +332,12 @@ The remaining data of each directory block is grouped by type:
 
   - 32-bit offset to the end of the index entries
 
-  - 160-bit SHA-1 over the extension types and their sizes (but not
+  - Hash over the extension types and their sizes (but not
 	their contents).  E.g. if we have "TREE" extension that is N-bytes
 	long, "REUC" extension that is M-bytes long, followed by "EOIE",
 	then the hash would be:
 
-	SHA-1("TREE" + <binary representation of N> +
+	Hash("TREE" + <binary representation of N> +
 		"REUC" + <binary representation of M>)
 
 == Index Entry Offset Table
diff --git a/Documentation/technical/pack-format.txt b/Documentation/technical/pack-format.txt
index 16cf7e83aa..f96b2e605f 100644
--- a/Documentation/technical/pack-format.txt
+++ b/Documentation/technical/pack-format.txt
@@ -1,6 +1,12 @@
 Git pack format
 ===============
 
+== Checksums and object IDs
+
+In a repository using the traditional SHA-1, pack checksums, index checksums,
+and object IDs (object names) mentioned below are all computed using SHA-1.
+Similarly, in SHA-256 repositories, these values are computed using SHA-256.
+
 == pack-*.pack files have the following format:
 
    - A header appears at the beginning and consists of the following:
@@ -26,7 +32,7 @@ Git pack format
 
      (deltified representation)
      n-byte type and length (3-bit type, (n-1)*7+4-bit length)
-     20-byte base object name if OBJ_REF_DELTA or a negative relative
+     base object name if OBJ_REF_DELTA or a negative relative
 	 offset from the delta object's position in the pack if this
 	 is an OBJ_OFS_DELTA object
      compressed delta data
@@ -34,7 +40,7 @@ Git pack format
      Observation: length of each object is encoded in a variable
      length format and is not constrained to 32-bit or anything.
 
-  - The trailer records 20-byte SHA-1 checksum of all of the above.
+  - The trailer records a pack checksum of all of the above.
 
 === Object types
 
@@ -58,8 +64,8 @@ ofs-delta and ref-delta, which is only valid in a pack file.
 
 Both ofs-delta and ref-delta store the "delta" to be applied to
 another object (called 'base object') to reconstruct the object. The
-difference between them is, ref-delta directly encodes 20-byte base
-object name. If the base object is in the same pack, ofs-delta encodes
+difference between them is, ref-delta directly encodes base object
+name. If the base object is in the same pack, ofs-delta encodes
 the offset of the base object in the pack instead.
 
 The base object could also be deltified if it's in the same pack.
@@ -143,14 +149,14 @@ This is the instruction reserved for future expansion.
     object is stored in the packfile as the offset from the
     beginning.
 
-    20-byte object name.
+    one object name of the appropriate size.
 
   - The file is concluded with a trailer:
 
-    A copy of the 20-byte SHA-1 checksum at the end of
-    corresponding packfile.
+    A copy of the pack checksum at the end of the corresponding
+    packfile.
 
-    20-byte SHA-1-checksum of all of the above.
+    Index checksum of all of the above.
 
 Pack Idx file:
 
@@ -198,7 +204,7 @@ Pack file entry: <+
         If it is not DELTA, then deflated bytes (the size above
 		is the size before compression).
 	If it is REF_DELTA, then
-	  20-byte base object name SHA-1 (the size above is the
+	  base object name (the size above is the
 		size of the delta data that follows).
           delta data, deflated.
 	If it is OFS_DELTA, then
@@ -227,9 +233,9 @@ Pack file entry: <+
 
   - A 256-entry fan-out table just like v1.
 
-  - A table of sorted 20-byte SHA-1 object names.  These are
-    packed together without offset values to reduce the cache
-    footprint of the binary search for a specific object name.
+  - A table of sorted object names.  These are packed together
+    without offset values to reduce the cache footprint of the
+    binary search for a specific object name.
 
   - A table of 4-byte CRC32 values of the packed object data.
     This is new in v2 so compressed data can be copied directly
@@ -248,10 +254,10 @@ Pack file entry: <+
 
   - The same trailer as a v1 pack file:
 
-    A copy of the 20-byte SHA-1 checksum at the end of
+    A copy of the pack checksum at the end of
     corresponding packfile.
 
-    20-byte SHA-1-checksum of all of the above.
+    Index checksum of all of the above.
 
 == multi-pack-index (MIDX) files have the following format:
 
@@ -334,4 +340,4 @@ CHUNK DATA:
 
 TRAILER:
 
-	20-byte SHA1-checksum of the above contents.
+	Index checksum of the above contents.
diff --git a/Documentation/technical/protocol-capabilities.txt b/Documentation/technical/protocol-capabilities.txt
index 36ccd14f97..124d716807 100644
--- a/Documentation/technical/protocol-capabilities.txt
+++ b/Documentation/technical/protocol-capabilities.txt
@@ -324,15 +324,19 @@ allow-tip-sha1-in-want
 ----------------------
 
 If the upload-pack server advertises this capability, fetch-pack may
-send "want" lines with SHA-1s that exist at the server but are not
-advertised by upload-pack.
+send "want" lines with object names that exist at the server but are not
+advertised by upload-pack. For historical reasons, the name of this
+capability contains "sha1". Object names are always given using the
+object format negotiated through the 'object-format' capability.
 
 allow-reachable-sha1-in-want
 ----------------------------
 
 If the upload-pack server advertises this capability, fetch-pack may
-send "want" lines with SHA-1s that exist at the server but are not
-advertised by upload-pack.
+send "want" lines with object names that exist at the server but are not
+advertised by upload-pack. For historical reasons, the name of this
+capability contains "sha1". Object names are always given using the
+object format negotiated through the 'object-format' capability.
 
 push-cert=<nonce>
 -----------------
diff --git a/Documentation/technical/shallow.txt b/Documentation/technical/shallow.txt
index 01dedfe9ff..f3738baa0f 100644
--- a/Documentation/technical/shallow.txt
+++ b/Documentation/technical/shallow.txt
@@ -13,7 +13,7 @@ pretend as if they are root commits (e.g. "git log" traversal
 stops after showing them; "git fsck" does not complain saying
 the commits listed on their "parent" lines do not exist).
 
-Each line contains exactly one SHA-1. When read, a commit_graft
+Each line contains exactly one object name. When read, a commit_graft
 will be constructed, which has nr_parent < 0 to make it easier
 to discern from user provided grafts.
 
diff --git a/apply.c b/apply.c
index 402d80602a..57afee5120 100644
--- a/apply.c
+++ b/apply.c
@@ -3740,6 +3740,7 @@ static int check_preimage(struct apply_state *state,
 
 #define EXISTS_IN_INDEX 1
 #define EXISTS_IN_WORKTREE 2
+#define EXISTS_IN_INDEX_AS_ITA 3
 
 static int check_to_create(struct apply_state *state,
 			   const char *new_name,
@@ -3747,10 +3748,23 @@ static int check_to_create(struct apply_state *state,
 {
 	struct stat nst;
 
-	if (state->check_index &&
-	    index_name_pos(state->repo->index, new_name, strlen(new_name)) >= 0 &&
-	    !ok_if_exists)
-		return EXISTS_IN_INDEX;
+	if (state->check_index && (!ok_if_exists || !state->cached)) {
+		int pos;
+
+		pos = index_name_pos(state->repo->index, new_name, strlen(new_name));
+		if (pos >= 0) {
+			struct cache_entry *ce = state->repo->index->cache[pos];
+
+			/* allow ITA, as they do not yet exist in the index */
+			if (!ok_if_exists && !(ce->ce_flags & CE_INTENT_TO_ADD))
+				return EXISTS_IN_INDEX;
+
+			/* ITA entries can never match working tree files */
+			if (!state->cached && (ce->ce_flags & CE_INTENT_TO_ADD))
+				return EXISTS_IN_INDEX_AS_ITA;
+		}
+	}
+
 	if (state->cached)
 		return 0;
 
@@ -3935,6 +3949,9 @@ static int check_patch(struct apply_state *state, struct patch *patch)
 		case EXISTS_IN_INDEX:
 			return error(_("%s: already exists in index"), new_name);
 			break;
+		case EXISTS_IN_INDEX_AS_ITA:
+			return error(_("%s: does not match index"), new_name);
+			break;
 		case EXISTS_IN_WORKTREE:
 			return error(_("%s: already exists in working directory"),
 				     new_name);
diff --git a/bisect.c b/bisect.c
index a088a0f82e..d42a3a3767 100644
--- a/bisect.c
+++ b/bisect.c
@@ -15,6 +15,7 @@
 #include "commit-slab.h"
 #include "commit-reach.h"
 #include "object-store.h"
+#include "dir.h"
 
 static struct oid_array good_revs;
 static struct oid_array skipped_revs;
@@ -88,15 +89,16 @@ static inline void weight_set(struct commit_list *elem, int weight)
 	**commit_weight_at(&commit_weight, elem->item) = weight;
 }
 
-static int count_interesting_parents(struct commit *commit)
+static int count_interesting_parents(struct commit *commit, unsigned bisect_flags)
 {
 	struct commit_list *p;
 	int count;
 
 	for (count = 0, p = commit->parents; p; p = p->next) {
-		if (p->item->object.flags & UNINTERESTING)
-			continue;
-		count++;
+		if (!(p->item->object.flags & UNINTERESTING))
+			count++;
+		if (bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY)
+			break;
 	}
 	return count;
 }
@@ -135,7 +137,7 @@ static void show_list(const char *debug, int counted, int nr,
 	for (p = list; p; p = p->next) {
 		struct commit_list *pp;
 		struct commit *commit = p->item;
-		unsigned flags = commit->object.flags;
+		unsigned commit_flags = commit->object.flags;
 		enum object_type type;
 		unsigned long size;
 		char *buf = read_object_file(&commit->object.oid, &type,
@@ -144,9 +146,9 @@ static void show_list(const char *debug, int counted, int nr,
 		int subject_len;
 
 		fprintf(stderr, "%c%c%c ",
-			(flags & TREESAME) ? ' ' : 'T',
-			(flags & UNINTERESTING) ? 'U' : ' ',
-			(flags & COUNTED) ? 'C' : ' ');
+			(commit_flags & TREESAME) ? ' ' : 'T',
+			(commit_flags & UNINTERESTING) ? 'U' : ' ',
+			(commit_flags & COUNTED) ? 'C' : ' ');
 		if (*commit_weight_at(&commit_weight, p->item))
 			fprintf(stderr, "%3d", weight(p));
 		else
@@ -171,9 +173,9 @@ static struct commit_list *best_bisection(struct commit_list *list, int nr)
 	best = list;
 	for (p = list; p; p = p->next) {
 		int distance;
-		unsigned flags = p->item->object.flags;
+		unsigned commit_flags = p->item->object.flags;
 
-		if (flags & TREESAME)
+		if (commit_flags & TREESAME)
 			continue;
 		distance = weight(p);
 		if (nr - distance < distance)
@@ -212,9 +214,9 @@ static struct commit_list *best_bisection_sorted(struct commit_list *list, int n
 
 	for (p = list, cnt = 0; p; p = p->next) {
 		int distance;
-		unsigned flags = p->item->object.flags;
+		unsigned commit_flags = p->item->object.flags;
 
-		if (flags & TREESAME)
+		if (commit_flags & TREESAME)
 			continue;
 		distance = weight(p);
 		if (nr - distance < distance)
@@ -259,7 +261,7 @@ static struct commit_list *best_bisection_sorted(struct commit_list *list, int n
  */
 static struct commit_list *do_find_bisection(struct commit_list *list,
 					     int nr, int *weights,
-					     int find_all)
+					     unsigned bisect_flags)
 {
 	int n, counted;
 	struct commit_list *p;
@@ -268,12 +270,12 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
 
 	for (n = 0, p = list; p; p = p->next) {
 		struct commit *commit = p->item;
-		unsigned flags = commit->object.flags;
+		unsigned commit_flags = commit->object.flags;
 
 		*commit_weight_at(&commit_weight, p->item) = &weights[n++];
-		switch (count_interesting_parents(commit)) {
+		switch (count_interesting_parents(commit, bisect_flags)) {
 		case 0:
-			if (!(flags & TREESAME)) {
+			if (!(commit_flags & TREESAME)) {
 				weight_set(p, 1);
 				counted++;
 				show_list("bisection 2 count one",
@@ -314,11 +316,13 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
 			continue;
 		if (weight(p) != -2)
 			continue;
+		if (bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY)
+			BUG("shouldn't be calling count-distance in fp mode");
 		weight_set(p, count_distance(p));
 		clear_distance(list);
 
 		/* Does it happen to be at exactly half-way? */
-		if (!find_all && halfway(p, nr))
+		if (!(bisect_flags & FIND_BISECTION_ALL) && halfway(p, nr))
 			return p;
 		counted++;
 	}
@@ -328,11 +332,14 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
 	while (counted < nr) {
 		for (p = list; p; p = p->next) {
 			struct commit_list *q;
-			unsigned flags = p->item->object.flags;
+			unsigned commit_flags = p->item->object.flags;
 
 			if (0 <= weight(p))
 				continue;
-			for (q = p->item->parents; q; q = q->next) {
+
+			for (q = p->item->parents;
+			     q;
+			     q = bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY ? NULL : q->next) {
 				if (q->item->object.flags & UNINTERESTING)
 					continue;
 				if (0 <= weight(q))
@@ -346,7 +353,7 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
 			 * add one for p itself if p is to be counted,
 			 * otherwise inherit it from q directly.
 			 */
-			if (!(flags & TREESAME)) {
+			if (!(commit_flags & TREESAME)) {
 				weight_set(p, weight(q)+1);
 				counted++;
 				show_list("bisection 2 count one",
@@ -356,21 +363,21 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
 				weight_set(p, weight(q));
 
 			/* Does it happen to be at exactly half-way? */
-			if (!find_all && halfway(p, nr))
+			if (!(bisect_flags & FIND_BISECTION_ALL) && halfway(p, nr))
 				return p;
 		}
 	}
 
 	show_list("bisection 2 counted all", counted, nr, list);
 
-	if (!find_all)
+	if (!(bisect_flags & FIND_BISECTION_ALL))
 		return best_bisection(list, nr);
 	else
 		return best_bisection_sorted(list, nr);
 }
 
 void find_bisection(struct commit_list **commit_list, int *reaches,
-		    int *all, int find_all)
+		    int *all, unsigned bisect_flags)
 {
 	int nr, on_list;
 	struct commit_list *list, *p, *best, *next, *last;
@@ -386,16 +393,16 @@ void find_bisection(struct commit_list **commit_list, int *reaches,
 	for (nr = on_list = 0, last = NULL, p = *commit_list;
 	     p;
 	     p = next) {
-		unsigned flags = p->item->object.flags;
+		unsigned commit_flags = p->item->object.flags;
 
 		next = p->next;
-		if (flags & UNINTERESTING) {
+		if (commit_flags & UNINTERESTING) {
 			free(p);
 			continue;
 		}
 		p->next = last;
 		last = p;
-		if (!(flags & TREESAME))
+		if (!(commit_flags & TREESAME))
 			nr++;
 		on_list++;
 	}
@@ -406,9 +413,9 @@ void find_bisection(struct commit_list **commit_list, int *reaches,
 	weights = xcalloc(on_list, sizeof(*weights));
 
 	/* Do the real work of finding bisection commit. */
-	best = do_find_bisection(list, nr, weights, find_all);
+	best = do_find_bisection(list, nr, weights, bisect_flags);
 	if (best) {
-		if (!find_all) {
+		if (!(bisect_flags & FIND_BISECTION_ALL)) {
 			list->item = best->item;
 			free_commit_list(list->next);
 			best = list;
@@ -454,6 +461,7 @@ static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
 static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
 static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
+static GIT_PATH_FUNC(git_path_bisect_first_parent, "BISECT_FIRST_PARENT")
 static GIT_PATH_FUNC(git_path_head_name, "head-name")
 
 static void read_bisect_paths(struct strvec *array)
@@ -983,7 +991,7 @@ void read_bisect_terms(const char **read_bad, const char **read_good)
  * If no_checkout is non-zero, the bisection process does not
  * checkout the trial commit but instead simply updates BISECT_HEAD.
  */
-enum bisect_error bisect_next_all(struct repository *r, const char *prefix, int no_checkout)
+enum bisect_error bisect_next_all(struct repository *r, const char *prefix)
 {
 	struct rev_info revs;
 	struct commit_list *tried;
@@ -991,21 +999,31 @@ enum bisect_error bisect_next_all(struct repository *r, const char *prefix, int
 	enum bisect_error res = BISECT_OK;
 	struct object_id *bisect_rev;
 	char *steps_msg;
+	int no_checkout = ref_exists("BISECT_HEAD");
+	unsigned bisect_flags = 0;
 
 	read_bisect_terms(&term_bad, &term_good);
 	if (read_bisect_refs())
 		die(_("reading bisect refs failed"));
 
+	if (file_exists(git_path_bisect_first_parent()))
+		bisect_flags |= FIND_BISECTION_FIRST_PARENT_ONLY;
+
+	if (skipped_revs.nr)
+		bisect_flags |= FIND_BISECTION_ALL;
+
 	res = check_good_are_ancestors_of_bad(r, prefix, no_checkout);
 	if (res)
 		return res;
 
 	bisect_rev_setup(r, &revs, prefix, "%s", "^%s", 1);
+
+	revs.first_parent_only = !!(bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY);
 	revs.limited = 1;
 
 	bisect_common(&revs);
 
-	find_bisection(&revs.commits, &reaches, &all, !!skipped_revs.nr);
+	find_bisection(&revs.commits, &reaches, &all, bisect_flags);
 	revs.commits = managed_skipped(revs.commits, &tried);
 
 	if (!revs.commits) {
@@ -1133,6 +1151,7 @@ int bisect_clean_state(void)
 	unlink_or_warn(git_path_bisect_names());
 	unlink_or_warn(git_path_bisect_run());
 	unlink_or_warn(git_path_bisect_terms());
+	unlink_or_warn(git_path_bisect_first_parent());
 	/* Cleanup head-name if it got left by an old version of git-bisect */
 	unlink_or_warn(git_path_head_name());
 	/*
diff --git a/bisect.h b/bisect.h
index 8bad8d8391..ec24ac2d7e 100644
--- a/bisect.h
+++ b/bisect.h
@@ -12,7 +12,7 @@ struct repository;
  * best commit, as chosen by `find_all`.
  */
 void find_bisection(struct commit_list **list, int *reaches, int *all,
-		    int find_all);
+		    unsigned bisect_flags);
 
 struct commit_list *filter_skipped(struct commit_list *list,
 				   struct commit_list **tried,
@@ -23,6 +23,9 @@ struct commit_list *filter_skipped(struct commit_list *list,
 #define BISECT_SHOW_ALL		(1<<0)
 #define REV_LIST_QUIET		(1<<1)
 
+#define FIND_BISECTION_ALL			(1u<<0)
+#define FIND_BISECTION_FIRST_PARENT_ONLY	(1u<<1)
+
 struct rev_list_info {
 	struct rev_info *revs;
 	int flags;
@@ -58,9 +61,7 @@ enum bisect_error {
 	BISECT_INTERNAL_SUCCESS_MERGE_BASE = -11
 };
 
-enum bisect_error bisect_next_all(struct repository *r,
-		    const char *prefix,
-		    int no_checkout);
+enum bisect_error bisect_next_all(struct repository *r, const char *prefix);
 
 int estimate_bisect_steps(int all);
 
diff --git a/blame.c b/blame.c
index 82fa16d658..1be1cd82a2 100644
--- a/blame.c
+++ b/blame.c
@@ -1184,6 +1184,7 @@ void blame_coalesce(struct blame_scoreboard *sb)
 	for (ent = sb->ent; ent && (next = ent->next); ent = next) {
 		if (ent->suspect == next->suspect &&
 		    ent->s_lno + ent->num_lines == next->s_lno &&
+		    ent->lno + ent->num_lines == next->lno &&
 		    ent->ignored == next->ignored &&
 		    ent->unblamable == next->unblamable) {
 			ent->num_lines += next->num_lines;
diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index d19300687f..cdda279b23 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -16,9 +16,10 @@ static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
 static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
 static GIT_PATH_FUNC(git_path_head_name, "head-name")
 static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
+static GIT_PATH_FUNC(git_path_bisect_first_parent, "BISECT_FIRST_PARENT")
 
 static const char * const git_bisect_helper_usage[] = {
-	N_("git bisect--helper --next-all [--no-checkout]"),
+	N_("git bisect--helper --next-all"),
 	N_("git bisect--helper --write-terms <bad_term> <good_term>"),
 	N_("git bisect--helper --bisect-clean-state"),
 	N_("git bisect--helper --bisect-reset [<commit>]"),
@@ -27,7 +28,7 @@ static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-next-check <good_term> <bad_term> [<term>]"),
 	N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
 	N_("git bisect--helper --bisect-start [--term-{old,good}=<term> --term-{new,bad}=<term>]"
-					     "[--no-checkout] [<bad> [<good>...]] [--] [<paths>...]"),
+					    " [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]"),
 	NULL
 };
 
@@ -420,9 +421,10 @@ finish:
 	return res;
 }
 
-static int bisect_start(struct bisect_terms *terms, int no_checkout,
-			const char **argv, int argc)
+static int bisect_start(struct bisect_terms *terms, const char **argv, int argc)
 {
+	int no_checkout = 0;
+	int first_parent_only = 0;
 	int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
 	int flags, pathspec_pos, res = 0;
 	struct string_list revs = STRING_LIST_INIT_DUP;
@@ -452,6 +454,8 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
 			break;
 		} else if (!strcmp(arg, "--no-checkout")) {
 			no_checkout = 1;
+		} else if (!strcmp(arg, "--first-parent")) {
+			first_parent_only = 1;
 		} else if (!strcmp(arg, "--term-good") ||
 			 !strcmp(arg, "--term-old")) {
 			i++;
@@ -576,6 +580,9 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
 	 */
 	write_file(git_path_bisect_start(), "%s\n", start_head.buf);
 
+	if (first_parent_only)
+		write_file(git_path_bisect_first_parent(), "\n");
+
 	if (no_checkout) {
 		if (get_oid(start_head.buf, &oid) < 0) {
 			res = error(_("invalid ref: '%s'"), start_head.buf);
@@ -631,7 +638,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_TERMS,
 		BISECT_START
 	} cmdmode = 0;
-	int no_checkout = 0, res = 0, nolog = 0;
+	int res = 0, nolog = 0;
 	struct option options[] = {
 		OPT_CMDMODE(0, "next-all", &cmdmode,
 			 N_("perform 'git bisect next'"), NEXT_ALL),
@@ -653,8 +660,6 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("print out the bisect terms"), BISECT_TERMS),
 		OPT_CMDMODE(0, "bisect-start", &cmdmode,
 			 N_("start the bisect session"), BISECT_START),
-		OPT_BOOL(0, "no-checkout", &no_checkout,
-			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_BOOL(0, "no-log", &nolog,
 			 N_("no log for BISECT_WRITE")),
 		OPT_END()
@@ -670,7 +675,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 
 	switch (cmdmode) {
 	case NEXT_ALL:
-		res = bisect_next_all(the_repository, prefix, no_checkout);
+		res = bisect_next_all(the_repository, prefix);
 		break;
 	case WRITE_TERMS:
 		if (argc != 2)
@@ -712,7 +717,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		break;
 	case BISECT_START:
 		set_terms(&terms, "bad", "good");
-		res = bisect_start(&terms, no_checkout, argv, argc);
+		res = bisect_start(&terms, argv, argc);
 		break;
 	default:
 		return error("BUG: unknown subcommand '%d'", cmdmode);
diff --git a/builtin/blame.c b/builtin/blame.c
index 94ef57c1cc..eb513fbe60 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -842,7 +842,7 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 	const char *contents_from = NULL;
 	const struct option options[] = {
 		OPT_BOOL(0, "incremental", &incremental, N_("Show blame entries as we find them, incrementally")),
-		OPT_BOOL('b', NULL, &blank_boundary, N_("Show blank SHA-1 for boundary commits (Default: off)")),
+		OPT_BOOL('b', NULL, &blank_boundary, N_("Do not show object names of boundary commits (Default: off)")),
 		OPT_BOOL(0, "root", &show_root, N_("Do not treat root commits as boundaries (Default: off)")),
 		OPT_BOOL(0, "show-stats", &show_stats, N_("Show work cost statistics")),
 		OPT_BOOL(0, "progress", &show_progress, N_("Force progress reporting")),
diff --git a/builtin/log.c b/builtin/log.c
index 33528fefa9..b58f8da09e 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -599,8 +599,8 @@ static int show_tree_object(const struct object_id *oid,
 static void show_setup_revisions_tweak(struct rev_info *rev,
 				       struct setup_revision_opt *opt)
 {
-	if (rev->ignore_merges) {
-		/* There was no "-m" on the command line */
+	if (rev->ignore_merges < 0) {
+		/* There was no "-m" variant on the command line */
 		rev->ignore_merges = 0;
 		if (!rev->first_parent_only && !rev->combine_merges) {
 			/* No "--first-parent", "-c", or "--cc" */
@@ -732,8 +732,7 @@ static void log_setup_revisions_tweak(struct rev_info *rev,
 	if (!rev->diffopt.output_format && rev->combine_merges)
 		rev->diffopt.output_format = DIFF_FORMAT_PATCH;
 
-	/* Turn -m on when --cc/-c was given */
-	if (rev->combine_merges)
+	if (rev->first_parent_only && rev->ignore_merges < 0)
 		rev->ignore_merges = 0;
 }
 
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index a9dcd25e46..725dd04519 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -521,7 +521,7 @@ int cmd_name_rev(int argc, const char **argv, const char *prefix)
 	int all = 0, transform_stdin = 0, allow_undefined = 1, always = 0, peel_tag = 0;
 	struct name_ref_data data = { 0, 0, STRING_LIST_INIT_NODUP, STRING_LIST_INIT_NODUP };
 	struct option opts[] = {
-		OPT_BOOL(0, "name-only", &data.name_only, N_("print only names (no SHA-1)")),
+		OPT_BOOL(0, "name-only", &data.name_only, N_("print only ref-based names (no object names)")),
 		OPT_BOOL(0, "tags", &data.tags_only, N_("only use tags to name the commits")),
 		OPT_STRING_LIST(0, "refs", &data.ref_filters, N_("pattern"),
 				   N_("only use refs matching <pattern>")),
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index a8692d27f1..5617c01b5a 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -3357,7 +3357,7 @@ static void get_object_list(int ac, const char **av)
 			if (starts_with(line, "--shallow ")) {
 				struct object_id oid;
 				if (get_oid_hex(line + 10, &oid))
-					die("not an SHA-1 '%s'", line + 10);
+					die("not an object name '%s'", line + 10);
 				register_shallow(the_repository, &oid);
 				use_bitmap_index = 0;
 				continue;
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index f520111eda..25c6c3b38d 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -637,8 +637,15 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 
 	if (bisect_list) {
 		int reaches, all;
+		unsigned bisect_flags = 0;
 
-		find_bisection(&revs.commits, &reaches, &all, bisect_find_all);
+		if (bisect_find_all)
+			bisect_flags |= FIND_BISECTION_ALL;
+
+		if (revs.first_parent_only)
+			bisect_flags |= FIND_BISECTION_FIRST_PARENT_ONLY;
+
+		find_bisection(&revs.commits, &reaches, &all, bisect_flags);
 
 		if (bisect_show_vars)
 			return show_bisect_vars(&info, reaches, all);
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 0fdb5da83b..700d44af5b 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1712,8 +1712,8 @@ _git_diff ()
 }
 
 __git_mergetools_common="diffuse diffmerge ecmerge emerge kdiff3 meld opendiff
-			tkdiff vimdiff gvimdiff xxdiff araxis p4merge bc
-			codecompare smerge
+			tkdiff vimdiff nvimdiff gvimdiff xxdiff araxis p4merge
+			bc codecompare smerge
 "
 
 _git_difftool ()
diff --git a/diff-lib.c b/diff-lib.c
index 25fd2dee19..50521e2093 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -219,7 +219,8 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 				continue;
 			} else if (revs->diffopt.ita_invisible_in_index &&
 				   ce_intent_to_add(ce)) {
-				diff_addremove(&revs->diffopt, '+', ce->ce_mode,
+				newmode = ce_mode_from_stat(ce, st.st_mode);
+				diff_addremove(&revs->diffopt, '+', newmode,
 					       &null_oid, 0, ce->name, 0);
 				continue;
 			}
diff --git a/git-bisect.sh b/git-bisect.sh
index f03fbb18f0..c7580e51a0 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -153,7 +153,7 @@ bisect_next() {
 	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD $TERM_GOOD|| exit
 
 	# Perform all bisection computation, display and checkout
-	git bisect--helper --next-all $(git rev-parse --verify -q BISECT_HEAD > /dev/null && echo --no-checkout)
+	git bisect--helper --next-all
 	res=$?
 
 	# Check if we should exit because bisection is finished
diff --git a/git-compat-util.h b/git-compat-util.h
index 5637114b8d..7a0fb7a045 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -252,8 +252,10 @@ typedef unsigned long uintptr_t;
 #ifdef PRECOMPOSE_UNICODE
 #include "compat/precompose_utf8.h"
 #else
-#define precompose_str(in,i_nfd2nfc)
-#define precompose_argv(c,v)
+static inline void precompose_argv(int argc, const char **argv)
+{
+	; /* nothing */
+}
 #define probe_utf8_pathname_composition()
 #endif
 
@@ -270,7 +272,9 @@ struct itimerval {
 #endif
 
 #ifdef NO_SETITIMER
-#define setitimer(which,value,ovalue)
+static inline int setitimer(int which, const struct itimerval *value, struct itimerval *newvalue) {
+	; /* nothing */
+}
 #endif
 
 #ifndef NO_LIBGEN_H
@@ -1231,8 +1235,14 @@ int warn_on_fopen_errors(const char *path);
 #endif
 
 #ifndef _POSIX_THREAD_SAFE_FUNCTIONS
-#define flockfile(fh)
-#define funlockfile(fh)
+static inline void flockfile(FILE *fh)
+{
+	; /* nothing */
+}
+static inline void funlockfile(FILE *fh)
+{
+	; /* nothing */
+}
 #define getc_unlocked(fh) getc(fh)
 #endif
 
diff --git a/git-mergetool--lib.sh b/git-mergetool--lib.sh
index 204a5acd66..2defef28cd 100644
--- a/git-mergetool--lib.sh
+++ b/git-mergetool--lib.sh
@@ -43,7 +43,14 @@ show_tool_names () {
 
 	shown_any=
 	( cd "$MERGE_TOOLS_DIR" && ls ) | {
-		while read toolname
+		while read scriptname
+		do
+			setup_tool "$scriptname" 2>/dev/null
+			variants="$variants$(list_tool_variants)\n"
+		done
+		variants="$(echo "$variants" | sort | uniq)"
+
+		for toolname in $variants
 		do
 			if setup_tool "$toolname" 2>/dev/null &&
 				(eval "$condition" "$toolname")
@@ -157,6 +164,10 @@ setup_tool () {
 		echo "$1"
 	}
 
+	list_tool_variants () {
+		echo "$tool"
+	}
+
 	# Most tools' exit codes cannot be trusted, so By default we ignore
 	# their exit code and check the merged file's modification time in
 	# check_unchanged() to determine whether or not the merge was
@@ -178,19 +189,26 @@ setup_tool () {
 		false
 	}
 
-
-	if ! test -f "$MERGE_TOOLS_DIR/$tool"
+	if test -f "$MERGE_TOOLS_DIR/$tool"
+	then
+		. "$MERGE_TOOLS_DIR/$tool"
+	elif test -f "$MERGE_TOOLS_DIR/${tool%[0-9]}"
 	then
+		. "$MERGE_TOOLS_DIR/${tool%[0-9]}"
+	else
 		setup_user_tool
 		return $?
 	fi
 
-	# Load the redefined functions
-	. "$MERGE_TOOLS_DIR/$tool"
 	# Now let the user override the default command for the tool.  If
 	# they have not done so then this will return 1 which we ignore.
 	setup_user_tool
 
+	if ! list_tool_variants | grep -q "^$tool$"
+	then
+		return 1
+	fi
+
 	if merge_mode && ! can_merge
 	then
 		echo "error: '$tool' can not be used to resolve merges" >&2
@@ -286,11 +304,14 @@ list_merge_tool_candidates () {
 		tools="$tools smerge"
 	fi
 	case "${VISUAL:-$EDITOR}" in
+	*nvim*)
+		tools="$tools nvimdiff vimdiff emerge"
+		;;
 	*vim*)
-		tools="$tools vimdiff emerge"
+		tools="$tools vimdiff nvimdiff emerge"
 		;;
 	*)
-		tools="$tools emerge vimdiff"
+		tools="$tools emerge vimdiff nvimdiff"
 		;;
 	esac
 }
diff --git a/git-rebase--preserve-merges.sh b/git-rebase--preserve-merges.sh
index dec90e9af6..b9c71d2a71 100644
--- a/git-rebase--preserve-merges.sh
+++ b/git-rebase--preserve-merges.sh
@@ -193,16 +193,6 @@ mark_action_done () {
 	fi
 }
 
-# Put the last action marked done at the beginning of the todo list
-# again. If there has not been an action marked done yet, leave the list of
-# items on the todo list unchanged.
-reschedule_last_action () {
-	tail -n 1 "$done" | cat - "$todo" >"$todo".new
-	sed -e \$d <"$done" >"$done".new
-	mv -f "$todo".new "$todo"
-	mv -f "$done".new "$done"
-}
-
 append_todo_help () {
 	gettext "
 Commands:
diff --git a/git-send-email.perl b/git-send-email.perl
index 36c47bae1d..1f425c0809 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -250,6 +250,7 @@ my $chain_reply_to = 0;
 my $use_xmailer = 1;
 my $validate = 1;
 my $target_xfer_encoding = 'auto';
+my $forbid_sendmail_variables = 1;
 
 my %config_bool_settings = (
     "thread" => \$thread,
@@ -263,6 +264,7 @@ my %config_bool_settings = (
     "multiedit" => \$multiedit,
     "annotate" => \$annotate,
     "xmailer" => \$use_xmailer,
+    "forbidsendmailvariables" => \$forbid_sendmail_variables,
 );
 
 my %config_settings = (
@@ -478,6 +480,12 @@ unless ($rc) {
     usage();
 }
 
+if ($forbid_sendmail_variables && (scalar Git::config_regexp("^sendmail[.]")) != 0) {
+	die __("fatal: found configuration options for 'sendmail'\n" .
+		"git-send-email is configured with the sendemail.* options - note the 'e'.\n" .
+		"Set sendemail.forbidSendmailVariables to false to disable this check.\n");
+}
+
 die __("Cannot run git format-patch from outside a repository\n")
 	if $format_patch and not $repo;
 
diff --git a/mergetools/bc b/mergetools/bc
index 3a69e60faa..a89086ee72 100644
--- a/mergetools/bc
+++ b/mergetools/bc
@@ -21,3 +21,8 @@ translate_merge_tool_path() {
 		echo bcompare
 	fi
 }
+
+list_tool_variants () {
+	echo bc
+	echo bc3
+}
diff --git a/mergetools/bc3 b/mergetools/bc3
deleted file mode 100644
index 5d8dd48184..0000000000
--- a/mergetools/bc3
+++ /dev/null
@@ -1 +0,0 @@
-. "$MERGE_TOOLS_DIR/bc"
diff --git a/mergetools/gvimdiff3 b/mergetools/gvimdiff3
deleted file mode 100644
index 04a5bb0ea8..0000000000
--- a/mergetools/gvimdiff3
+++ /dev/null
@@ -1 +0,0 @@
-. "$MERGE_TOOLS_DIR/vimdiff"
diff --git a/mergetools/gvimdiff2 b/mergetools/nvimdiff
index 04a5bb0ea8..04a5bb0ea8 100644
--- a/mergetools/gvimdiff2
+++ b/mergetools/nvimdiff
diff --git a/mergetools/vimdiff b/mergetools/vimdiff
index 10d86f3e19..abc8ce4ec4 100644
--- a/mergetools/vimdiff
+++ b/mergetools/vimdiff
@@ -5,7 +5,7 @@ diff_cmd () {
 
 merge_cmd () {
 	case "$1" in
-	gvimdiff|vimdiff)
+	*vimdiff)
 		if $base_present
 		then
 			"$merge_tool_path" -f -d -c '4wincmd w | wincmd J' \
@@ -15,11 +15,11 @@ merge_cmd () {
 				"$LOCAL" "$MERGED" "$REMOTE"
 		fi
 		;;
-	gvimdiff2|vimdiff2)
+	*vimdiff2)
 		"$merge_tool_path" -f -d -c 'wincmd l' \
 			"$LOCAL" "$MERGED" "$REMOTE"
 		;;
-	gvimdiff3|vimdiff3)
+	*vimdiff3)
 		if $base_present
 		then
 			"$merge_tool_path" -f -d -c 'hid | hid | hid' \
@@ -34,10 +34,13 @@ merge_cmd () {
 
 translate_merge_tool_path() {
 	case "$1" in
-	gvimdiff|gvimdiff2|gvimdiff3)
+	nvimdiff*)
+		echo nvim
+		;;
+	gvimdiff*)
 		echo gvim
 		;;
-	vimdiff|vimdiff2|vimdiff3)
+	vimdiff*)
 		echo vim
 		;;
 	esac
@@ -46,3 +49,11 @@ translate_merge_tool_path() {
 exit_code_trustable () {
 	true
 }
+
+list_tool_variants () {
+	for prefix in '' g n; do
+		for suffix in '' 2 3; do
+			echo "${prefix}vimdiff${suffix}"
+		done
+	done
+}
diff --git a/mergetools/vimdiff2 b/mergetools/vimdiff2
deleted file mode 100644
index 04a5bb0ea8..0000000000
--- a/mergetools/vimdiff2
+++ /dev/null
@@ -1 +0,0 @@
-. "$MERGE_TOOLS_DIR/vimdiff"
diff --git a/mergetools/vimdiff3 b/mergetools/vimdiff3
deleted file mode 100644
index 04a5bb0ea8..0000000000
--- a/mergetools/vimdiff3
+++ /dev/null
@@ -1 +0,0 @@
-. "$MERGE_TOOLS_DIR/vimdiff"
diff --git a/parse-options.h b/parse-options.h
index 46af942093..7030d8f3da 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -314,7 +314,7 @@ int parse_opt_passthru_argv(const struct option *, const char *, int);
 #define OPT__FORCE(var, h, f) OPT_COUNTUP_F('f', "force",   (var), (h), (f))
 #define OPT__ABBREV(var)  \
 	{ OPTION_CALLBACK, 0, "abbrev", (var), N_("n"),	\
-	  N_("use <n> digits to display SHA-1s"),	\
+	  N_("use <n> digits to display object names"),	\
 	  PARSE_OPT_OPTARG, &parse_opt_abbrev_cb, 0 }
 #define OPT__COLOR(var, h) \
 	OPT_COLOR_FLAG(0, "color", (var), (h))
diff --git a/perl/Git.pm b/perl/Git.pm
index 54c9ed0dde..10df990959 100644
--- a/perl/Git.pm
+++ b/perl/Git.pm
@@ -723,6 +723,32 @@ sub config_int {
 	return scalar _config_common({'kind' => '--int'}, @_);
 }
 
+=item config_regexp ( RE )
+
+Retrieve the list of configuration key names matching the regular
+expression C<RE>. The return value is a list of strings matching
+this regex.
+
+=cut
+
+sub config_regexp {
+	my ($self, $regex) = _maybe_self(@_);
+	try {
+		my @cmd = ('config', '--name-only', '--get-regexp', $regex);
+		unshift @cmd, $self if $self;
+		my @matches = command(@cmd);
+		return @matches;
+	} catch Git::Error::Command with {
+		my $E = shift;
+		if ($E->value() == 1) {
+			my @matches = ();
+			return @matches;
+		} else {
+			throw $E;
+		}
+	};
+}
+
 # Common subroutine to implement bulk of what the config* family of methods
 # do. This currently wraps command('config') so it is not so fast.
 sub _config_common {
diff --git a/progress.c b/progress.c
index 3eda914518..31014e6fca 100644
--- a/progress.c
+++ b/progress.c
@@ -319,9 +319,12 @@ static void finish_if_sparse(struct progress *progress)
 
 void stop_progress(struct progress **p_progress)
 {
+	if (!p_progress)
+		BUG("don't provide NULL to stop_progress");
+
 	finish_if_sparse(*p_progress);
 
-	if (p_progress && *p_progress) {
+	if (*p_progress) {
 		trace2_data_intmax("progress", the_repository, "total_objects",
 				   (*p_progress)->total);
 
@@ -338,7 +341,12 @@ void stop_progress(struct progress **p_progress)
 
 void stop_progress_msg(struct progress **p_progress, const char *msg)
 {
-	struct progress *progress = *p_progress;
+	struct progress *progress;
+
+	if (!p_progress)
+		BUG("don't provide NULL to stop_progress_msg");
+
+	progress = *p_progress;
 	if (!progress)
 		return;
 	*p_progress = NULL;
diff --git a/refs.c b/refs.c
index 9e28912f73..cf91711968 100644
--- a/refs.c
+++ b/refs.c
@@ -708,10 +708,9 @@ int dwim_log(const char *str, int len, struct object_id *oid, char **log)
 
 static int is_per_worktree_ref(const char *refname)
 {
-	return !strcmp(refname, "HEAD") ||
-		starts_with(refname, "refs/worktree/") ||
-		starts_with(refname, "refs/bisect/") ||
-		starts_with(refname, "refs/rewritten/");
+	return starts_with(refname, "refs/worktree/") ||
+	       starts_with(refname, "refs/bisect/") ||
+	       starts_with(refname, "refs/rewritten/");
 }
 
 static int is_pseudoref_syntax(const char *refname)
@@ -771,102 +770,6 @@ long get_files_ref_lock_timeout_ms(void)
 	return timeout_ms;
 }
 
-static int write_pseudoref(const char *pseudoref, const struct object_id *oid,
-			   const struct object_id *old_oid, struct strbuf *err)
-{
-	const char *filename;
-	int fd;
-	struct lock_file lock = LOCK_INIT;
-	struct strbuf buf = STRBUF_INIT;
-	int ret = -1;
-
-	if (!oid)
-		return 0;
-
-	strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
-
-	filename = git_path("%s", pseudoref);
-	fd = hold_lock_file_for_update_timeout(&lock, filename, 0,
-					       get_files_ref_lock_timeout_ms());
-	if (fd < 0) {
-		strbuf_addf(err, _("could not open '%s' for writing: %s"),
-			    filename, strerror(errno));
-		goto done;
-	}
-
-	if (old_oid) {
-		struct object_id actual_old_oid;
-
-		if (read_ref(pseudoref, &actual_old_oid)) {
-			if (!is_null_oid(old_oid)) {
-				strbuf_addf(err, _("could not read ref '%s'"),
-					    pseudoref);
-				rollback_lock_file(&lock);
-				goto done;
-			}
-		} else if (is_null_oid(old_oid)) {
-			strbuf_addf(err, _("ref '%s' already exists"),
-				    pseudoref);
-			rollback_lock_file(&lock);
-			goto done;
-		} else if (!oideq(&actual_old_oid, old_oid)) {
-			strbuf_addf(err, _("unexpected object ID when writing '%s'"),
-				    pseudoref);
-			rollback_lock_file(&lock);
-			goto done;
-		}
-	}
-
-	if (write_in_full(fd, buf.buf, buf.len) < 0) {
-		strbuf_addf(err, _("could not write to '%s'"), filename);
-		rollback_lock_file(&lock);
-		goto done;
-	}
-
-	commit_lock_file(&lock);
-	ret = 0;
-done:
-	strbuf_release(&buf);
-	return ret;
-}
-
-static int delete_pseudoref(const char *pseudoref, const struct object_id *old_oid)
-{
-	const char *filename;
-
-	filename = git_path("%s", pseudoref);
-
-	if (old_oid && !is_null_oid(old_oid)) {
-		struct lock_file lock = LOCK_INIT;
-		int fd;
-		struct object_id actual_old_oid;
-
-		fd = hold_lock_file_for_update_timeout(
-				&lock, filename, 0,
-				get_files_ref_lock_timeout_ms());
-		if (fd < 0) {
-			error_errno(_("could not open '%s' for writing"),
-				    filename);
-			return -1;
-		}
-		if (read_ref(pseudoref, &actual_old_oid))
-			die(_("could not read ref '%s'"), pseudoref);
-		if (!oideq(&actual_old_oid, old_oid)) {
-			error(_("unexpected object ID when deleting '%s'"),
-			      pseudoref);
-			rollback_lock_file(&lock);
-			return -1;
-		}
-
-		unlink(filename);
-		rollback_lock_file(&lock);
-	} else {
-		unlink(filename);
-	}
-
-	return 0;
-}
-
 int refs_delete_ref(struct ref_store *refs, const char *msg,
 		    const char *refname,
 		    const struct object_id *old_oid,
@@ -875,11 +778,6 @@ int refs_delete_ref(struct ref_store *refs, const char *msg,
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 
-	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
-		assert(refs == get_main_ref_store(the_repository));
-		return delete_pseudoref(refname, old_oid);
-	}
-
 	transaction = ref_store_transaction_begin(refs, &err);
 	if (!transaction ||
 	    ref_transaction_delete(transaction, refname, old_oid,
@@ -1210,18 +1108,13 @@ int refs_update_ref(struct ref_store *refs, const char *msg,
 	struct strbuf err = STRBUF_INIT;
 	int ret = 0;
 
-	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
-		assert(refs == get_main_ref_store(the_repository));
-		ret = write_pseudoref(refname, new_oid, old_oid, &err);
-	} else {
-		t = ref_store_transaction_begin(refs, &err);
-		if (!t ||
-		    ref_transaction_update(t, refname, new_oid, old_oid,
-					   flags, msg, &err) ||
-		    ref_transaction_commit(t, &err)) {
-			ret = 1;
-			ref_transaction_free(t);
-		}
+	t = ref_store_transaction_begin(refs, &err);
+	if (!t ||
+	    ref_transaction_update(t, refname, new_oid, old_oid, flags, msg,
+				   &err) ||
+	    ref_transaction_commit(t, &err)) {
+		ret = 1;
+		ref_transaction_free(t);
 	}
 	if (ret) {
 		const char *str = _("update_ref failed for ref '%s': %s");
@@ -2044,7 +1937,7 @@ static int run_transaction_hook(struct ref_transaction *transaction,
 	if (hook == &hook_not_found)
 		return ret;
 	if (!hook)
-		hook = find_hook("reference-transaction");
+		hook = xstrdup_or_null(find_hook("reference-transaction"));
 	if (!hook) {
 		hook = &hook_not_found;
 		return ret;
diff --git a/revision.c b/revision.c
index 3dcf689341..96630e3186 100644
--- a/revision.c
+++ b/revision.c
@@ -1815,7 +1815,7 @@ void repo_init_revisions(struct repository *r,
 
 	revs->repo = r;
 	revs->abbrev = DEFAULT_ABBREV;
-	revs->ignore_merges = 1;
+	revs->ignore_merges = -1;
 	revs->simplify_history = 1;
 	revs->pruning.repo = r;
 	revs->pruning.flags.recursive = 1;
@@ -2345,6 +2345,15 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->diffopt.flags.tree_in_recursive = 1;
 	} else if (!strcmp(arg, "-m")) {
 		revs->ignore_merges = 0;
+	} else if ((argcount = parse_long_opt("diff-merges", argv, &optarg))) {
+		if (!strcmp(optarg, "off")) {
+			revs->ignore_merges = 1;
+		} else {
+			die(_("unknown value for --diff-merges: %s"), optarg);
+		}
+		return argcount;
+	} else if (!strcmp(arg, "--no-diff-merges")) {
+		revs->ignore_merges = 1;
 	} else if (!strcmp(arg, "-c")) {
 		revs->diff = 1;
 		revs->dense_combined_merges = 0;
@@ -2854,8 +2863,10 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 			copy_pathspec(&revs->diffopt.pathspec,
 				      &revs->prune_data);
 	}
-	if (revs->combine_merges)
+	if (revs->combine_merges && revs->ignore_merges < 0)
 		revs->ignore_merges = 0;
+	if (revs->ignore_merges < 0)
+		revs->ignore_merges = 1;
 	if (revs->combined_all_paths && !revs->combine_merges)
 		die("--combined-all-paths makes no sense without -c or --cc");
 
@@ -2889,9 +2900,6 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 	if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
 		die("cannot use --grep-reflog without --walk-reflogs");
 
-	if (revs->first_parent_only && revs->bisect)
-		die(_("--first-parent is incompatible with --bisect"));
-
 	if (revs->line_level_traverse &&
 	    (revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
 		die(_("-L does not yet support diff formats besides -p and -s"));
diff --git a/revision.h b/revision.h
index 889216c2d8..c1e5bcf139 100644
--- a/revision.h
+++ b/revision.h
@@ -190,11 +190,11 @@ struct rev_info {
 			show_root_diff:1,
 			no_commit_id:1,
 			verbose_header:1,
-			ignore_merges:1,
 			combine_merges:1,
 			combined_all_paths:1,
 			dense_combined_merges:1,
 			always_show_header:1;
+	int             ignore_merges:2;
 
 	/* Format info */
 	int		show_notes;
diff --git a/sequencer.c b/sequencer.c
index cc3f8fa88e..2425896911 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -355,7 +355,7 @@ static int get_message(struct commit *commit, struct commit_message *out)
 	subject_len = find_commit_subject(out->message, &subject);
 
 	out->subject = xmemdupz(subject, subject_len);
-	out->label = xstrfmt("%s... %s", abbrev, out->subject);
+	out->label = xstrfmt("%s (%s)", abbrev, out->subject);
 	out->parent_label = xstrfmt("parent of %s", out->label);
 
 	return 0;
@@ -5178,13 +5178,14 @@ int complete_action(struct repository *r, struct replay_opts *opts, unsigned fla
 		    struct string_list *commands, unsigned autosquash,
 		    struct todo_list *todo_list)
 {
-	const char *shortonto, *todo_file = rebase_path_todo();
+	char shortonto[GIT_MAX_HEXSZ + 1];
+	const char *todo_file = rebase_path_todo();
 	struct todo_list new_todo = TODO_LIST_INIT;
 	struct strbuf *buf = &todo_list->buf, buf2 = STRBUF_INIT;
 	struct object_id oid = onto->object.oid;
 	int res;
 
-	shortonto = find_unique_abbrev(&oid, DEFAULT_ABBREV);
+	find_unique_abbrev_r(shortonto, &oid, DEFAULT_ABBREV);
 
 	if (buf->len == 0) {
 		struct todo_item *item = append_new_todo(todo_list);
diff --git a/sideband.c b/sideband.c
index ef851113c4..0a60662fa6 100644
--- a/sideband.c
+++ b/sideband.c
@@ -147,7 +147,7 @@ int demultiplex_sideband(const char *me, char *buf, int len,
 	switch (band) {
 	case 3:
 		if (die_on_error)
-			die("remote error: %s", buf + 1);
+			die(_("remote error: %s"), buf + 1);
 		strbuf_addf(scratch, "%s%s", scratch->len ? "\n" : "",
 			    DISPLAY_PREFIX);
 		maybe_colorize_sideband(scratch, buf + 1, len);
diff --git a/t/t0040-parse-options.sh b/t/t0040-parse-options.sh
index f8178ee4e3..14cafc138b 100755
--- a/t/t0040-parse-options.sh
+++ b/t/t0040-parse-options.sh
@@ -44,7 +44,7 @@ Magic arguments
     --no-ambiguous        negative ambiguity
 
 Standard options
-    --abbrev[=<n>]        use <n> digits to display SHA-1s
+    --abbrev[=<n>]        use <n> digits to display object names
     -v, --verbose         be verbose
     -n, --dry-run         dry run
     -q, --quiet           be quiet
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index d0d36750bc..770e7be363 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -160,10 +160,10 @@ test_expect_success 'core.logAllRefUpdates=always creates reflog by default' '
 	git reflog exists $outside
 '
 
-test_expect_success 'core.logAllRefUpdates=always creates no reflog for ORIG_HEAD' '
+test_expect_success 'core.logAllRefUpdates=always creates reflog for ORIG_HEAD' '
 	test_config core.logAllRefUpdates always &&
 	git update-ref ORIG_HEAD $A &&
-	test_must_fail git reflog exists ORIG_HEAD
+	git reflog exists ORIG_HEAD
 '
 
 test_expect_success '--no-create-reflog overrides core.logAllRefUpdates=always' '
@@ -475,57 +475,57 @@ test_expect_success 'git cat-file blob master@{2005-05-26 23:42}:F (expect OTHER
 
 test_expect_success 'given old value for missing pseudoref, do not create' '
 	test_must_fail git update-ref PSEUDOREF $A $B 2>err &&
-	test_path_is_missing .git/PSEUDOREF &&
-	test_i18ngrep "could not read ref" err
+	test_must_fail git rev-parse PSEUDOREF &&
+	test_i18ngrep "unable to resolve reference" err
 '
 
 test_expect_success 'create pseudoref' '
 	git update-ref PSEUDOREF $A &&
-	test $A = $(cat .git/PSEUDOREF)
+	test $A = $(git rev-parse PSEUDOREF)
 '
 
 test_expect_success 'overwrite pseudoref with no old value given' '
 	git update-ref PSEUDOREF $B &&
-	test $B = $(cat .git/PSEUDOREF)
+	test $B = $(git rev-parse PSEUDOREF)
 '
 
 test_expect_success 'overwrite pseudoref with correct old value' '
 	git update-ref PSEUDOREF $C $B &&
-	test $C = $(cat .git/PSEUDOREF)
+	test $C = $(git rev-parse PSEUDOREF)
 '
 
 test_expect_success 'do not overwrite pseudoref with wrong old value' '
 	test_must_fail git update-ref PSEUDOREF $D $E 2>err &&
-	test $C = $(cat .git/PSEUDOREF) &&
-	test_i18ngrep "unexpected object ID" err
+	test $C = $(git rev-parse PSEUDOREF) &&
+	test_i18ngrep "cannot lock ref.*expected" err
 '
 
 test_expect_success 'delete pseudoref' '
 	git update-ref -d PSEUDOREF &&
-	test_path_is_missing .git/PSEUDOREF
+	test_must_fail git rev-parse PSEUDOREF
 '
 
 test_expect_success 'do not delete pseudoref with wrong old value' '
 	git update-ref PSEUDOREF $A &&
 	test_must_fail git update-ref -d PSEUDOREF $B 2>err &&
-	test $A = $(cat .git/PSEUDOREF) &&
-	test_i18ngrep "unexpected object ID" err
+	test $A = $(git rev-parse PSEUDOREF) &&
+	test_i18ngrep "cannot lock ref.*expected" err
 '
 
 test_expect_success 'delete pseudoref with correct old value' '
 	git update-ref -d PSEUDOREF $A &&
-	test_path_is_missing .git/PSEUDOREF
+	test_must_fail git rev-parse PSEUDOREF
 '
 
 test_expect_success 'create pseudoref with old OID zero' '
 	git update-ref PSEUDOREF $A $Z &&
-	test $A = $(cat .git/PSEUDOREF)
+	test $A = $(git rev-parse PSEUDOREF)
 '
 
 test_expect_success 'do not overwrite pseudoref with old OID zero' '
 	test_when_finished git update-ref -d PSEUDOREF &&
 	test_must_fail git update-ref PSEUDOREF $B $Z 2>err &&
-	test $A = $(cat .git/PSEUDOREF) &&
+	test $A = $(git rev-parse PSEUDOREF) &&
 	test_i18ngrep "already exists" err
 '
 
diff --git a/t/t1405-main-ref-store.sh b/t/t1405-main-ref-store.sh
index 331899ddc4..74af927fba 100755
--- a/t/t1405-main-ref-store.sh
+++ b/t/t1405-main-ref-store.sh
@@ -31,7 +31,10 @@ test_expect_success 'create_symref(FOO, refs/heads/master)' '
 test_expect_success 'delete_refs(FOO, refs/tags/new-tag)' '
 	git rev-parse FOO -- &&
 	git rev-parse refs/tags/new-tag -- &&
-	$RUN delete-refs 0 nothing FOO refs/tags/new-tag &&
+	m=$(git rev-parse master) &&
+	REF_NO_DEREF=1 &&
+	$RUN delete-refs $REF_NO_DEREF nothing FOO refs/tags/new-tag &&
+	test_must_fail git rev-parse --symbolic-full-name FOO &&
 	test_must_fail git rev-parse FOO -- &&
 	test_must_fail git rev-parse refs/tags/new-tag --
 '
diff --git a/t/t1416-ref-transaction-hooks.sh b/t/t1416-ref-transaction-hooks.sh
index da58d867a5..f6e741c6c0 100755
--- a/t/t1416-ref-transaction-hooks.sh
+++ b/t/t1416-ref-transaction-hooks.sh
@@ -7,6 +7,7 @@ test_description='reference transaction hooks'
 test_expect_success setup '
 	mkdir -p .git/hooks &&
 	test_commit PRE &&
+	PRE_OID=$(git rev-parse PRE) &&
 	test_commit POST &&
 	POST_OID=$(git rev-parse POST)
 '
@@ -106,4 +107,30 @@ test_expect_success 'hook gets all queued updates in aborted state' '
 	test_cmp expect actual
 '
 
+test_expect_success 'interleaving hook calls succeed' '
+	test_when_finished "rm -r target-repo.git" &&
+
+	git init --bare target-repo.git &&
+
+	write_script target-repo.git/hooks/reference-transaction <<-\EOF &&
+		echo $0 "$@" >>actual
+	EOF
+
+	write_script target-repo.git/hooks/update <<-\EOF &&
+		echo $0 "$@" >>actual
+	EOF
+
+	cat >expect <<-EOF &&
+		hooks/update refs/tags/PRE $ZERO_OID $PRE_OID
+		hooks/reference-transaction prepared
+		hooks/reference-transaction committed
+		hooks/update refs/tags/POST $ZERO_OID $POST_OID
+		hooks/reference-transaction prepared
+		hooks/reference-transaction committed
+	EOF
+
+	git push ./target-repo.git PRE POST &&
+	test_cmp expect target-repo.git/actual
+'
+
 test_done
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 9744e88760..07a1617351 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -256,7 +256,7 @@ test_expect_success 'stop on conflicting pick' '
 	D
 	=======
 	G
-	>>>>>>> $commit... G
+	>>>>>>> $commit (G)
 	EOF
 	git tag new-branch1 &&
 	test_must_fail git rebase -i master &&
@@ -1791,6 +1791,12 @@ test_expect_success 'correct error message for commit --amend after empty pick'
 	test_i18ngrep "middle of a rebase -- cannot amend." err
 '
 
+test_expect_success 'todo has correct onto hash' '
+	GIT_SEQUENCE_EDITOR=cat git rebase -i no-conflict-branch~4 no-conflict-branch >actual &&
+	onto=$(git rev-parse --short HEAD~4) &&
+	test_i18ngrep "^# Rebase ..* onto $onto" actual
+'
+
 # This must be the last test in this file
 test_expect_success '$EDITOR and friends are unchanged' '
 	test_editor_unchanged
diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index f107622a9e..a21adcf0e4 100755
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -283,12 +283,12 @@ test_expect_success 'failed cherry-pick describes conflict in work tree' '
 	a
 	=======
 	c
-	>>>>>>> objid picked
+	>>>>>>> objid (picked)
 	EOF
 
 	test_must_fail git cherry-pick picked &&
 
-	sed "s/[a-f0-9]*\.\.\./objid/" foo >actual &&
+	sed "s/[a-f0-9]* (/objid (/" foo >actual &&
 	test_cmp expected actual
 '
 
@@ -298,16 +298,16 @@ test_expect_success 'diff3 -m style' '
 	cat <<-EOF >expected &&
 	<<<<<<< HEAD
 	a
-	||||||| parent of objid picked
+	||||||| parent of objid (picked)
 	b
 	=======
 	c
-	>>>>>>> objid picked
+	>>>>>>> objid (picked)
 	EOF
 
 	test_must_fail git cherry-pick picked &&
 
-	sed "s/[a-f0-9]*\.\.\./objid/" foo >actual &&
+	sed "s/[a-f0-9]* (/objid (/" foo >actual &&
 	test_cmp expected actual
 '
 
@@ -319,7 +319,7 @@ test_expect_success 'revert also handles conflicts sanely' '
 	a
 	=======
 	b
-	>>>>>>> parent of objid picked
+	>>>>>>> parent of objid (picked)
 	EOF
 	{
 		git checkout picked -- foo &&
@@ -345,7 +345,7 @@ test_expect_success 'revert also handles conflicts sanely' '
 	test_must_fail git update-index --refresh -q &&
 	test_must_fail git diff-index --exit-code HEAD &&
 	test_cmp expected-stages actual-stages &&
-	sed "s/[a-f0-9]*\.\.\./objid/" foo >actual &&
+	sed "s/[a-f0-9]* (/objid (/" foo >actual &&
 	test_cmp expected actual
 '
 
@@ -429,16 +429,16 @@ test_expect_success 'revert conflict, diff3 -m style' '
 	cat <<-EOF >expected &&
 	<<<<<<< HEAD
 	a
-	||||||| objid picked
+	||||||| objid (picked)
 	c
 	=======
 	b
-	>>>>>>> parent of objid picked
+	>>>>>>> parent of objid (picked)
 	EOF
 
 	test_must_fail git revert picked &&
 
-	sed "s/[a-f0-9]*\.\.\./objid/" foo >actual &&
+	sed "s/[a-f0-9]* (/objid (/" foo >actual &&
 	test_cmp expected actual
 '
 
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index 3f60f7d96c..5f97dd6d65 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -297,6 +297,9 @@ log --root --patch-with-stat --summary master
 log --root -c --patch-with-stat --summary master
 # improved by Timo's patch
 log --root --cc --patch-with-stat --summary master
+log --no-diff-merges -p --first-parent master
+log --diff-merges=off -p --first-parent master
+log --first-parent --diff-merges=off -p master
 log -p --first-parent master
 log -m -p --first-parent master
 log -m -p master
diff --git a/t/t4013/diff.log_--diff-merges=off_-p_--first-parent_master b/t/t4013/diff.log_--diff-merges=off_-p_--first-parent_master
new file mode 100644
index 0000000000..194e893c94
--- /dev/null
+++ b/t/t4013/diff.log_--diff-merges=off_-p_--first-parent_master
@@ -0,0 +1,78 @@
+$ git log --diff-merges=off -p --first-parent master
+commit 59d314ad6f356dd08601a4cd5e530381da3e3c64
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+diff --git a/dir/sub b/dir/sub
+index 8422d40..cead32e 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -2,3 +2,5 @@ A
+ B
+ C
+ D
++E
++F
+diff --git a/file1 b/file1
+new file mode 100644
+index 0000000..b1e6722
+--- /dev/null
++++ b/file1
+@@ -0,0 +1,3 @@
++A
++B
++C
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..8422d40 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++C
++D
+diff --git a/file0 b/file0
+index 01e79c3..b414108 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++4
++5
++6
+diff --git a/file2 b/file2
+deleted file mode 100644
+index 01e79c3..0000000
+--- a/file2
++++ /dev/null
+@@ -1,3 +0,0 @@
+-1
+-2
+-3
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/t/t4013/diff.log_--first-parent_--diff-merges=off_-p_master b/t/t4013/diff.log_--first-parent_--diff-merges=off_-p_master
new file mode 100644
index 0000000000..5d7461a167
--- /dev/null
+++ b/t/t4013/diff.log_--first-parent_--diff-merges=off_-p_master
@@ -0,0 +1,78 @@
+$ git log --first-parent --diff-merges=off -p master
+commit 80e25ffa65bcdbe82ef654b4d06dbbde7945c37f
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+diff --git a/dir/sub b/dir/sub
+index 8422d40..cead32e 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -2,3 +2,5 @@ A
+ B
+ C
+ D
++E
++F
+diff --git a/file1 b/file1
+new file mode 100644
+index 0000000..b1e6722
+--- /dev/null
++++ b/file1
+@@ -0,0 +1,3 @@
++A
++B
++C
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..8422d40 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++C
++D
+diff --git a/file0 b/file0
+index 01e79c3..b414108 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++4
++5
++6
+diff --git a/file2 b/file2
+deleted file mode 100644
+index 01e79c3..0000000
+--- a/file2
++++ /dev/null
+@@ -1,3 +0,0 @@
+-1
+-2
+-3
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/t/t4013/diff.log_--no-diff-merges_-p_--first-parent_master b/t/t4013/diff.log_--no-diff-merges_-p_--first-parent_master
new file mode 100644
index 0000000000..597002232e
--- /dev/null
+++ b/t/t4013/diff.log_--no-diff-merges_-p_--first-parent_master
@@ -0,0 +1,78 @@
+$ git log --no-diff-merges -p --first-parent master
+commit 59d314ad6f356dd08601a4cd5e530381da3e3c64
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+diff --git a/dir/sub b/dir/sub
+index 8422d40..cead32e 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -2,3 +2,5 @@ A
+ B
+ C
+ D
++E
++F
+diff --git a/file1 b/file1
+new file mode 100644
+index 0000000..b1e6722
+--- /dev/null
++++ b/file1
+@@ -0,0 +1,3 @@
++A
++B
++C
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..8422d40 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++C
++D
+diff --git a/file0 b/file0
+index 01e79c3..b414108 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++4
++5
++6
+diff --git a/file2 b/file2
+deleted file mode 100644
+index 01e79c3..0000000
+--- a/file2
++++ /dev/null
+@@ -1,3 +0,0 @@
+-1
+-2
+-3
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/t/t4013/diff.log_-p_--first-parent_master b/t/t4013/diff.log_-p_--first-parent_master
index 3fc896d424..28840ebea1 100644
--- a/t/t4013/diff.log_-p_--first-parent_master
+++ b/t/t4013/diff.log_-p_--first-parent_master
@@ -6,6 +6,28 @@ Date:   Mon Jun 26 00:04:00 2006 +0000
 
     Merge branch 'side'
 
+diff --git a/dir/sub b/dir/sub
+index cead32e..992913c 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -4,3 +4,5 @@ C
+ D
+ E
+ F
++1
++2
+diff --git a/file0 b/file0
+index b414108..10a8a9f 100644
+--- a/file0
++++ b/file0
+@@ -4,3 +4,6 @@
+ 4
+ 5
+ 6
++A
++B
++C
+
 commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
 Author: A U Thor <author@example.com>
 Date:   Mon Jun 26 00:02:00 2006 +0000
diff --git a/t/t4018/fortran-block-data b/t/t4018/fortran-block-data
new file mode 100644
index 0000000000..63d4e21d0a
--- /dev/null
+++ b/t/t4018/fortran-block-data
@@ -0,0 +1,5 @@
+       BLOCK DATA RIGHT
+       
+       COMMON /B/ C, ChangeMe
+       DATA C, ChangeMe  / 2.0, 6.0 / 
+       END 
diff --git a/t/t4018/fortran-comment b/t/t4018/fortran-comment
new file mode 100644
index 0000000000..7b10d17658
--- /dev/null
+++ b/t/t4018/fortran-comment
@@ -0,0 +1,13 @@
+      module a
+
+      contains
+
+      ! subroutine wrong
+      subroutine RIGHT
+      ! subroutine wrong
+
+      real ChangeMe
+
+      end subroutine RIGHT
+
+      end module a
diff --git a/t/t4018/fortran-comment-keyword b/t/t4018/fortran-comment-keyword
new file mode 100644
index 0000000000..e9206a5379
--- /dev/null
+++ b/t/t4018/fortran-comment-keyword
@@ -0,0 +1,14 @@
+      module a
+
+      contains
+
+      subroutine RIGHT (funcA, funcB)
+
+      real funcA  ! grid function a
+      real funcB  ! grid function b
+
+      real ChangeMe
+
+      end subroutine RIGHT
+
+      end module a
diff --git a/t/t4018/fortran-comment-legacy b/t/t4018/fortran-comment-legacy
new file mode 100644
index 0000000000..53cd062c1e
--- /dev/null
+++ b/t/t4018/fortran-comment-legacy
@@ -0,0 +1,13 @@
+      module a
+
+      contains
+
+C subroutine wrong
+      subroutine RIGHT
+C subroutine wrong
+
+      real ChangeMe
+
+      end subroutine RIGHT
+
+      end module a
diff --git a/t/t4018/fortran-comment-legacy-star b/t/t4018/fortran-comment-legacy-star
new file mode 100644
index 0000000000..2cbcdc3d8a
--- /dev/null
+++ b/t/t4018/fortran-comment-legacy-star
@@ -0,0 +1,13 @@
+      module a
+
+      contains
+
+* subroutine wrong
+      subroutine RIGHT
+* subroutine wrong
+
+      real ChangeMe
+
+      end subroutine RIGHT
+
+      end module a
diff --git a/t/t4018/fortran-external-function b/t/t4018/fortran-external-function
new file mode 100644
index 0000000000..5a2d85d3aa
--- /dev/null
+++ b/t/t4018/fortran-external-function
@@ -0,0 +1,9 @@
+function RIGHT(a, b) result(c)
+
+integer, intent(in) :: ChangeMe
+integer, intent(in) :: b
+integer, intent(out) :: c
+
+c = a+b
+
+end function RIGHT
diff --git a/t/t4018/fortran-external-subroutine b/t/t4018/fortran-external-subroutine
new file mode 100644
index 0000000000..4ce85fea13
--- /dev/null
+++ b/t/t4018/fortran-external-subroutine
@@ -0,0 +1,5 @@
+subroutine RIGHT
+
+real ChangeMe
+
+end subroutine RIGHT
diff --git a/t/t4018/fortran-module b/t/t4018/fortran-module
new file mode 100644
index 0000000000..c4b737dac3
--- /dev/null
+++ b/t/t4018/fortran-module
@@ -0,0 +1,5 @@
+module RIGHT
+
+use ChangeMe
+
+end module RIGHT
diff --git a/t/t4018/fortran-module-procedure b/t/t4018/fortran-module-procedure
new file mode 100644
index 0000000000..1ce6d854c2
--- /dev/null
+++ b/t/t4018/fortran-module-procedure
@@ -0,0 +1,13 @@
+ module RIGHT
+
+   implicit none
+   private
+
+   interface letters  ! generic interface
+      module procedure aaaa, &
+                       bbbb, &
+                       ChangeMe, &
+                       dddd
+   end interface
+   
+end module RIGHT
diff --git a/t/t4018/fortran-program b/t/t4018/fortran-program
new file mode 100644
index 0000000000..4616895e4b
--- /dev/null
+++ b/t/t4018/fortran-program
@@ -0,0 +1,5 @@
+program RIGHT
+
+call ChangeMe
+
+end program RIGHT
diff --git a/t/t4140-apply-ita.sh b/t/t4140-apply-ita.sh
new file mode 100755
index 0000000000..c614eaf04c
--- /dev/null
+++ b/t/t4140-apply-ita.sh
@@ -0,0 +1,56 @@
+#!/bin/sh
+
+test_description='git apply of i-t-a file'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	test_write_lines 1 2 3 4 5 >blueprint &&
+
+	cat blueprint >test-file &&
+	git add -N test-file &&
+	git diff >creation-patch &&
+	grep "new file mode 100644" creation-patch &&
+
+	rm -f test-file &&
+	git diff >deletion-patch &&
+	grep "deleted file mode 100644" deletion-patch
+'
+
+test_expect_success 'apply creation patch to ita path (--cached)' '
+	git rm -f test-file &&
+	cat blueprint >test-file &&
+	git add -N test-file &&
+
+	git apply --cached creation-patch &&
+	git cat-file blob :test-file >actual &&
+	test_cmp blueprint actual
+'
+
+test_expect_success 'apply creation patch to ita path (--index)' '
+	git rm -f test-file &&
+	cat blueprint >test-file &&
+	git add -N test-file &&
+	rm -f test-file &&
+
+	test_must_fail git apply --index creation-patch
+'
+
+test_expect_success 'apply deletion patch to ita path (--cached)' '
+	git rm -f test-file &&
+	cat blueprint >test-file &&
+	git add -N test-file &&
+
+	git apply --cached deletion-patch &&
+	test_must_fail git ls-files --stage --error-unmatch test-file
+'
+
+test_expect_success 'apply deletion patch to ita path (--index)' '
+	cat blueprint >test-file &&
+	git add -N test-file &&
+
+	test_must_fail git apply --index deletion-patch &&
+	git ls-files --stage --error-unmatch test-file
+'
+
+test_done
diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index 3bb0e4ff8f..fc4d55dcb2 100755
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -128,8 +128,8 @@ test_expect_success 'rev-list can negate index objects' '
 	test_cmp expect actual
 '
 
-test_expect_success '--bisect and --first-parent can not be combined' '
-	test_must_fail git rev-list --bisect --first-parent HEAD
+test_expect_success '--bisect and --first-parent can be combined' '
+	git rev-list --bisect --first-parent HEAD
 '
 
 test_expect_success '--header shows a NUL after each commit' '
diff --git a/t/t6002-rev-list-bisect.sh b/t/t6002-rev-list-bisect.sh
index a661408038..b95a0212ad 100755
--- a/t/t6002-rev-list-bisect.sh
+++ b/t/t6002-rev-list-bisect.sh
@@ -263,4 +263,49 @@ test_expect_success 'rev-parse --bisect can default to good/bad refs' '
 	test_cmp expect.sorted actual.sorted
 '
 
+test_output_expect_success '--bisect --first-parent' 'git rev-list --bisect --first-parent E ^F' <<EOF
+e4
+EOF
+
+test_output_expect_success '--first-parent' 'git rev-list --first-parent E ^F' <<EOF
+E
+e1
+e2
+e3
+e4
+e5
+e6
+e7
+e8
+EOF
+
+test_output_expect_success '--bisect-vars --first-parent' 'git rev-list --bisect-vars --first-parent E ^F' <<EOF
+bisect_rev='e5'
+bisect_nr=4
+bisect_good=4
+bisect_bad=3
+bisect_all=9
+bisect_steps=2
+EOF
+
+test_expect_success '--bisect-all --first-parent' '
+	cat >expect.unsorted <<-EOF &&
+	$(git rev-parse E) (tag: E, dist=0)
+	$(git rev-parse e1) (tag: e1, dist=1)
+	$(git rev-parse e2) (tag: e2, dist=2)
+	$(git rev-parse e3) (tag: e3, dist=3)
+	$(git rev-parse e4) (tag: e4, dist=4)
+	$(git rev-parse e5) (tag: e5, dist=4)
+	$(git rev-parse e6) (tag: e6, dist=3)
+	$(git rev-parse e7) (tag: e7, dist=2)
+	$(git rev-parse e8) (tag: e8, dist=1)
+	EOF
+
+	# expect results to be ordered by distance (descending),
+	# commit hash (ascending)
+	sort -k4,4r -k1,1 expect.unsorted >expect &&
+	git rev-list --bisect-all --first-parent E ^F >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 36d9b2b2e4..b886529e59 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -243,32 +243,30 @@ test_expect_success 'bisect skip: with commit both bad and skipped' '
 '
 
 # We want to automatically find the commit that
-# introduced "Another" into hello.
-test_expect_success \
-    '"git bisect run" simple case' \
-    'echo "#"\!"/bin/sh" > test_script.sh &&
-     echo "grep Another hello > /dev/null" >> test_script.sh &&
-     echo "test \$? -ne 0" >> test_script.sh &&
-     chmod +x test_script.sh &&
-     git bisect start &&
-     git bisect good $HASH1 &&
-     git bisect bad $HASH4 &&
-     git bisect run ./test_script.sh > my_bisect_log.txt &&
-     grep "$HASH3 is the first bad commit" my_bisect_log.txt &&
-     git bisect reset'
+# added "Another" into hello.
+test_expect_success '"git bisect run" simple case' '
+	write_script test_script.sh <<-\EOF &&
+	! grep Another hello >/dev/null
+	EOF
+	git bisect start &&
+	git bisect good $HASH1 &&
+	git bisect bad $HASH4 &&
+	git bisect run ./test_script.sh >my_bisect_log.txt &&
+	grep "$HASH3 is the first bad commit" my_bisect_log.txt &&
+	git bisect reset
+'
 
 # We want to automatically find the commit that
-# introduced "Ciao" into hello.
-test_expect_success \
-    '"git bisect run" with more complex "git bisect start"' \
-    'echo "#"\!"/bin/sh" > test_script.sh &&
-     echo "grep Ciao hello > /dev/null" >> test_script.sh &&
-     echo "test \$? -ne 0" >> test_script.sh &&
-     chmod +x test_script.sh &&
-     git bisect start $HASH4 $HASH1 &&
-     git bisect run ./test_script.sh > my_bisect_log.txt &&
-     grep "$HASH4 is the first bad commit" my_bisect_log.txt &&
-     git bisect reset'
+# added "Ciao" into hello.
+test_expect_success '"git bisect run" with more complex "git bisect start"' '
+	write_script test_script.sh <<-\EOF &&
+	! grep Ciao hello >/dev/null
+	EOF
+	git bisect start $HASH4 $HASH1 &&
+	git bisect run ./test_script.sh >my_bisect_log.txt &&
+	grep "$HASH4 is the first bad commit" my_bisect_log.txt &&
+	git bisect reset
+'
 
 # $HASH1 is good, $HASH5 is bad, we skip $HASH3
 # but $HASH4 is good,
@@ -295,24 +293,17 @@ HASH6=
 test_expect_success 'bisect run & skip: cannot tell between 2' '
 	add_line_into_file "6: Yet a line." hello &&
 	HASH6=$(git rev-parse --verify HEAD) &&
-	echo "#"\!"/bin/sh" > test_script.sh &&
-	echo "sed -ne \\\$p hello | grep Ciao > /dev/null && exit 125" >> test_script.sh &&
-	echo "grep line hello > /dev/null" >> test_script.sh &&
-	echo "test \$? -ne 0" >> test_script.sh &&
-	chmod +x test_script.sh &&
+	write_script test_script.sh <<-\EOF &&
+	sed -ne \$p hello | grep Ciao >/dev/null && exit 125
+	! grep line hello >/dev/null
+	EOF
 	git bisect start $HASH6 $HASH1 &&
-	if git bisect run ./test_script.sh > my_bisect_log.txt
-	then
-		echo Oops, should have failed.
-		false
-	else
-		test $? -eq 2 &&
-		grep "first bad commit could be any of" my_bisect_log.txt &&
-		! grep $HASH3 my_bisect_log.txt &&
-		! grep $HASH6 my_bisect_log.txt &&
-		grep $HASH4 my_bisect_log.txt &&
-		grep $HASH5 my_bisect_log.txt
-	fi
+	test_expect_code 2 git bisect run ./test_script.sh >my_bisect_log.txt &&
+	grep "first bad commit could be any of" my_bisect_log.txt &&
+	! grep $HASH3 my_bisect_log.txt &&
+	! grep $HASH6 my_bisect_log.txt &&
+	grep $HASH4 my_bisect_log.txt &&
+	grep $HASH5 my_bisect_log.txt
 '
 
 HASH7=
@@ -320,14 +311,13 @@ test_expect_success 'bisect run & skip: find first bad' '
 	git bisect reset &&
 	add_line_into_file "7: Should be the last line." hello &&
 	HASH7=$(git rev-parse --verify HEAD) &&
-	echo "#"\!"/bin/sh" > test_script.sh &&
-	echo "sed -ne \\\$p hello | grep Ciao > /dev/null && exit 125" >> test_script.sh &&
-	echo "sed -ne \\\$p hello | grep day > /dev/null && exit 125" >> test_script.sh &&
-	echo "grep Yet hello > /dev/null" >> test_script.sh &&
-	echo "test \$? -ne 0" >> test_script.sh &&
-	chmod +x test_script.sh &&
+	write_script test_script.sh <<-\EOF &&
+	sed -ne \$p hello | grep Ciao >/dev/null && exit 125
+	sed -ne \$p hello | grep day >/dev/null && exit 125
+	! grep Yet hello >/dev/null
+	EOF
 	git bisect start $HASH7 $HASH1 &&
-	git bisect run ./test_script.sh > my_bisect_log.txt &&
+	git bisect run ./test_script.sh >my_bisect_log.txt &&
 	grep "$HASH6 is the first bad commit" my_bisect_log.txt
 '
 
@@ -458,6 +448,24 @@ test_expect_success 'many merge bases creation' '
 	grep "$SIDE_HASH5" merge_bases.txt
 '
 
+# We want to automatically find the merge that
+# added "line" into hello.
+test_expect_success '"git bisect run --first-parent" simple case' '
+	git rev-list --first-parent $B_HASH ^$HASH4 >first_parent_chain.txt &&
+	write_script test_script.sh <<-\EOF &&
+	grep $(git rev-parse HEAD) first_parent_chain.txt || exit -1
+	! grep line hello >/dev/null
+	EOF
+	git bisect start --first-parent &&
+	test_path_is_file ".git/BISECT_FIRST_PARENT" &&
+	git bisect good $HASH4 &&
+	git bisect bad $B_HASH &&
+	git bisect run ./test_script.sh >my_bisect_log.txt &&
+	grep "$B_HASH is the first bad commit" my_bisect_log.txt &&
+	git bisect reset &&
+	test_path_is_missing .git/BISECT_FIRST_PARENT
+'
+
 test_expect_success 'good merge bases when good and bad are siblings' '
 	git bisect start "$B_HASH" "$A_HASH" > my_bisect_log.txt &&
 	test_i18ngrep "merge base must be tested" my_bisect_log.txt &&
diff --git a/t/t6020-merge-df.sh b/t/t6400-merge-df.sh
index 400a4cd139..400a4cd139 100755
--- a/t/t6020-merge-df.sh
+++ b/t/t6400-merge-df.sh
diff --git a/t/t6021-merge-criss-cross.sh b/t/t6401-merge-criss-cross.sh
index 9d5e992878..9d5e992878 100755
--- a/t/t6021-merge-criss-cross.sh
+++ b/t/t6401-merge-criss-cross.sh
diff --git a/t/t6022-merge-rename.sh b/t/t6402-merge-rename.sh
index bbbba3dcbf..bbbba3dcbf 100755
--- a/t/t6022-merge-rename.sh
+++ b/t/t6402-merge-rename.sh
diff --git a/t/t6023-merge-file.sh b/t/t6403-merge-file.sh
index 2f421d967a..2f421d967a 100755
--- a/t/t6023-merge-file.sh
+++ b/t/t6403-merge-file.sh
diff --git a/t/t6024-recursive-merge.sh b/t/t6404-recursive-merge.sh
index 332cfc53fd..332cfc53fd 100755
--- a/t/t6024-recursive-merge.sh
+++ b/t/t6404-recursive-merge.sh
diff --git a/t/t6025-merge-symlinks.sh b/t/t6405-merge-symlinks.sh
index 6c0a90d044..6c0a90d044 100755
--- a/t/t6025-merge-symlinks.sh
+++ b/t/t6405-merge-symlinks.sh
diff --git a/t/t6026-merge-attr.sh b/t/t6406-merge-attr.sh
index 76a55f838c..76a55f838c 100755
--- a/t/t6026-merge-attr.sh
+++ b/t/t6406-merge-attr.sh
diff --git a/t/t6027-merge-binary.sh b/t/t6407-merge-binary.sh
index 4e6c7cb77e..4e6c7cb77e 100755
--- a/t/t6027-merge-binary.sh
+++ b/t/t6407-merge-binary.sh
diff --git a/t/t6028-merge-up-to-date.sh b/t/t6408-merge-up-to-date.sh
index 7763c1ba98..7763c1ba98 100755
--- a/t/t6028-merge-up-to-date.sh
+++ b/t/t6408-merge-up-to-date.sh
diff --git a/t/t6029-merge-subtree.sh b/t/t6409-merge-subtree.sh
index 793f0c8bf3..793f0c8bf3 100755
--- a/t/t6029-merge-subtree.sh
+++ b/t/t6409-merge-subtree.sh
diff --git a/t/t6031-merge-filemode.sh b/t/t6411-merge-filemode.sh
index 87741efad3..87741efad3 100755
--- a/t/t6031-merge-filemode.sh
+++ b/t/t6411-merge-filemode.sh
diff --git a/t/t6032-merge-large-rename.sh b/t/t6412-merge-large-rename.sh
index 80777386dc..80777386dc 100755
--- a/t/t6032-merge-large-rename.sh
+++ b/t/t6412-merge-large-rename.sh
diff --git a/t/t6033-merge-crlf.sh b/t/t6413-merge-crlf.sh
index e8d65eefb5..e8d65eefb5 100755
--- a/t/t6033-merge-crlf.sh
+++ b/t/t6413-merge-crlf.sh
diff --git a/t/t6034-merge-rename-nocruft.sh b/t/t6414-merge-rename-nocruft.sh
index a25e730460..a25e730460 100755
--- a/t/t6034-merge-rename-nocruft.sh
+++ b/t/t6414-merge-rename-nocruft.sh
diff --git a/t/t6035-merge-dir-to-symlink.sh b/t/t6415-merge-dir-to-symlink.sh
index 2eddcc7664..2eddcc7664 100755
--- a/t/t6035-merge-dir-to-symlink.sh
+++ b/t/t6415-merge-dir-to-symlink.sh
diff --git a/t/t6036-recursive-corner-cases.sh b/t/t6416-recursive-corner-cases.sh
index b3bf462617..fd98989b14 100755
--- a/t/t6036-recursive-corner-cases.sh
+++ b/t/t6416-recursive-corner-cases.sh
@@ -452,7 +452,7 @@ test_expect_success 'git detects conflict merging criss-cross+modify/delete, rev
 #
 # So choice 5 at least provides some kind of conflict for the original case,
 # and can merge cleanly as expected with D1 and E3.  It also made things just
-# slightly funny for merging D1 and e$, where E4 is defined as:
+# slightly funny for merging D1 and E4, where E4 is defined as:
 #   Commit E4: Merge B & C, modifying 'a' and renaming to 'a2', and deleting 'a/'
 # in this case, we'll get a rename/rename(1to2) conflict because a~$UNIQUE
 # gets renamed to 'a' in D1 and to 'a2' in E4.  But that's better than having
@@ -1144,7 +1144,7 @@ test_expect_failure 'check symlink add/add' '
 		test_must_fail git merge -s recursive E^0 &&
 
 		git ls-files -s >out &&
-		test_line_count = 2 out &&
+		test_line_count = 3 out &&
 		git ls-files -u >out &&
 		test_line_count = 2 out &&
 		git ls-files -o >out &&
diff --git a/t/t6037-merge-ours-theirs.sh b/t/t6417-merge-ours-theirs.sh
index 0aebc6c028..0aebc6c028 100755
--- a/t/t6037-merge-ours-theirs.sh
+++ b/t/t6417-merge-ours-theirs.sh
diff --git a/t/t6038-merge-text-auto.sh b/t/t6418-merge-text-auto.sh
index 89c86d4e56..30983d18b1 100755
--- a/t/t6038-merge-text-auto.sh
+++ b/t/t6418-merge-text-auto.sh
@@ -197,7 +197,8 @@ test_expect_success 'Test delete/normalize conflict' '
 	git commit -m "remove file" &&
 	git checkout master &&
 	git reset --hard a^ &&
-	git merge side
+	git merge side &&
+	test_path_is_missing file
 '
 
 test_done
diff --git a/t/t6039-merge-ignorecase.sh b/t/t6419-merge-ignorecase.sh
index 531850d834..531850d834 100755
--- a/t/t6039-merge-ignorecase.sh
+++ b/t/t6419-merge-ignorecase.sh
diff --git a/t/t6042-merge-rename-corner-cases.sh b/t/t6422-merge-rename-corner-cases.sh
index f163893ff9..3375eaf4e7 100755
--- a/t/t6042-merge-rename-corner-cases.sh
+++ b/t/t6422-merge-rename-corner-cases.sh
@@ -457,7 +457,7 @@ test_expect_success 'handle rename-with-content-merge vs. add' '
 		git checkout A^0 &&
 
 		test_must_fail git merge -s recursive B^0 >out &&
-		test_i18ngrep "CONFLICT (rename/add)" out &&
+		test_i18ngrep "CONFLICT (.*/add)" out &&
 
 		git ls-files -s >out &&
 		test_line_count = 2 out &&
@@ -503,7 +503,7 @@ test_expect_success 'handle rename-with-content-merge vs. add, merge other way'
 		git checkout B^0 &&
 
 		test_must_fail git merge -s recursive A^0 >out &&
-		test_i18ngrep "CONFLICT (rename/add)" out &&
+		test_i18ngrep "CONFLICT (.*/add)" out &&
 
 		git ls-files -s >out &&
 		test_line_count = 2 out &&
@@ -583,7 +583,7 @@ test_expect_success 'handle rename/rename (2to1) conflict correctly' '
 		git checkout B^0 &&
 
 		test_must_fail git merge -s recursive C^0 >out &&
-		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		test_i18ngrep "CONFLICT (\(.*\)/\1)" out &&
 
 		git ls-files -s >out &&
 		test_line_count = 2 out &&
@@ -886,12 +886,17 @@ test_expect_failure 'rad-check: rename/add/delete conflict' '
 		git checkout B^0 &&
 		test_must_fail git merge -s recursive A^0 >out 2>err &&
 
-		# Not sure whether the output should contain just one
-		# "CONFLICT (rename/add/delete)" line, or if it should break
-		# it into a pair of "CONFLICT (rename/delete)" and
-		# "CONFLICT (rename/add)"; allow for either.
-		test_i18ngrep "CONFLICT (rename.*add)" out &&
-		test_i18ngrep "CONFLICT (rename.*delete)" out &&
+		# Instead of requiring the output to contain one combined line
+		#   CONFLICT (rename/add/delete)
+		# or perhaps two lines:
+		#   CONFLICT (rename/add): new file collides with rename target
+		#   CONFLICT (rename/delete): rename source removed on other side
+		# and instead of requiring "rename/add" instead of "add/add",
+		# be flexible in the type of console output message(s) reported
+		# for this particular case; we will be more stringent about the
+		# contents of the index and working directory.
+		test_i18ngrep "CONFLICT (.*/add)" out &&
+		test_i18ngrep "CONFLICT (rename.*/delete)" out &&
 		test_must_be_empty err &&
 
 		git ls-files -s >file_count &&
@@ -899,14 +904,14 @@ test_expect_failure 'rad-check: rename/add/delete conflict' '
 		git ls-files -u >file_count &&
 		test_line_count = 2 file_count &&
 		git ls-files -o >file_count &&
-		test_line_count = 2 file_count &&
+		test_line_count = 3 file_count &&
 
 		git rev-parse >actual \
 			:2:bar :3:bar &&
 		git rev-parse >expect \
 			B:bar  A:bar  &&
 
-		test_cmp file_is_missing foo &&
+		test_path_is_missing foo &&
 		# bar should have two-way merged contents of the different
 		# versions of bar; check that content from both sides is
 		# present.
@@ -954,11 +959,17 @@ test_expect_failure 'rrdd-check: rename/rename(2to1)/delete/delete conflict' '
 		git checkout A^0 &&
 		test_must_fail git merge -s recursive B^0 >out 2>err &&
 
-		# Not sure whether the output should contain just one
-		# "CONFLICT (rename/rename/delete/delete)" line, or if it
-		# should break it into three: "CONFLICT (rename/rename)" and
-		# two "CONFLICT (rename/delete)" lines; allow for either.
-		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		# Instead of requiring the output to contain one combined line
+		#   CONFLICT (rename/rename/delete/delete)
+		# or perhaps two lines:
+		#   CONFLICT (rename/rename): ...
+		#   CONFLICT (rename/delete): info about pair 1
+		#   CONFLICT (rename/delete): info about pair 2
+		# and instead of requiring "rename/rename" instead of "add/add",
+		# be flexible in the type of console output message(s) reported
+		# for this particular case; we will be more stringent about the
+		# contents of the index and working directory.
+		test_i18ngrep "CONFLICT (\(.*\)/\1)" out &&
 		test_i18ngrep "CONFLICT (rename.*delete)" out &&
 		test_must_be_empty err &&
 
@@ -967,15 +978,15 @@ test_expect_failure 'rrdd-check: rename/rename(2to1)/delete/delete conflict' '
 		git ls-files -u >file_count &&
 		test_line_count = 2 file_count &&
 		git ls-files -o >file_count &&
-		test_line_count = 2 file_count &&
+		test_line_count = 3 file_count &&
 
 		git rev-parse >actual \
 			:2:baz :3:baz &&
 		git rev-parse >expect \
 			O:foo  O:bar  &&
 
-		test_cmp file_is_missing foo &&
-		test_cmp file_is_missing bar &&
+		test_path_is_missing foo &&
+		test_path_is_missing bar &&
 		# baz should have two-way merged contents of the original
 		# contents of foo and bar; check that content from both sides
 		# is present.
@@ -1042,25 +1053,25 @@ test_expect_failure 'mod6-check: chains of rename/rename(1to2) and rename/rename
 		test_must_be_empty err &&
 
 		git ls-files -s >file_count &&
-		test_line_count = 6 file_count &&
+		test_line_count = 9 file_count &&
 		git ls-files -u >file_count &&
-		test_line_count = 6 file_count &&
+		test_line_count = 9 file_count &&
 		git ls-files -o >file_count &&
 		test_line_count = 3 file_count &&
 
 		test_seq 10 20 >merged-one &&
 		test_seq 51 60 >merged-five &&
 		# Determine what the merge of three would give us.
-		test_seq 30 40 >three-side-A &&
+		test_seq 31 39 >three-base &&
+		test_seq 31 40 >three-side-A &&
 		test_seq 31 39 >three-side-B &&
-		echo forty >three-side-B &&
-		>empty &&
+		echo forty >>three-side-B &&
 		test_must_fail git merge-file \
-			-L "HEAD" \
+			-L "HEAD:four" \
 			-L "" \
-			-L "B^0" \
-			three-side-A empty three-side-B &&
-		sed -e "s/^\([<=>]\)/\1\1\1/" three-side-A >merged-three &&
+			-L "B^0:two" \
+			three-side-A three-base three-side-B &&
+		sed -e "s/^\([<=>]\)/\1\1/" three-side-A >merged-three &&
 
 		# Verify the index is as expected
 		git rev-parse >actual         \
@@ -1075,6 +1086,7 @@ test_expect_failure 'mod6-check: chains of rename/rename(1to2) and rename/rename
 
 		git cat-file -p :2:two >expect &&
 		git cat-file -p :3:two >other &&
+		>empty &&
 		test_must_fail git merge-file    \
 			-L "HEAD"  -L ""  -L "B^0" \
 			expect     empty  other &&
diff --git a/t/t6043-merge-rename-directories.sh b/t/t6423-merge-rename-directories.sh
index 83792c5ef1..f7ecbb886d 100755
--- a/t/t6043-merge-rename-directories.sh
+++ b/t/t6423-merge-rename-directories.sh
@@ -275,7 +275,7 @@ test_expect_success '1d: Directory renames cause a rename/rename(2to1) conflict'
 		git checkout A^0 &&
 
 		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
-		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		test_i18ngrep "CONFLICT (\(.*\)/\1)" out &&
 
 		git ls-files -s >out &&
 		test_line_count = 8 out &&
@@ -1686,7 +1686,7 @@ test_expect_success '7b: rename/rename(2to1), but only due to transitive rename'
 		git checkout A^0 &&
 
 		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
-		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		test_i18ngrep "CONFLICT (\(.*\)/\1)" out &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -2260,24 +2260,23 @@ test_expect_success '8d: rename/delete...or not?' '
 #   Commit B: w/{b,c}, z/d
 #
 # Possible Resolutions:
-#   w/o dir-rename detection: z/d, CONFLICT(z/b -> y/b vs. w/b),
-#                                  CONFLICT(z/c -> y/c vs. w/c)
-#   Currently expected:       y/d, CONFLICT(z/b -> y/b vs. w/b),
-#                                  CONFLICT(z/c -> y/c vs. w/c)
-#   Optimal:                  ??
+#   if z not considered renamed: z/d, CONFLICT(z/b -> y/b vs. w/b),
+#                                     CONFLICT(z/c -> y/c vs. w/c)
+#   if z->y rename considered:   y/d, CONFLICT(z/b -> y/b vs. w/b),
+#                                     CONFLICT(z/c -> y/c vs. w/c)
+#   Optimal:                     ??
 #
 # Notes: In commit A, directory z got renamed to y.  In commit B, directory z
 #        did NOT get renamed; the directory is still present; instead it is
 #        considered to have just renamed a subset of paths in directory z
-#        elsewhere.  Therefore, the directory rename done in commit A to z/
-#        applies to z/d and maps it to y/d.
+#        elsewhere.  However, this is much like testcase 6b (where commit B
+#        moves all the original paths out of z/ but opted to keep d
+#        within z/).  This makes it hard to judge where d should end up.
 #
 #        It's possible that users would get confused about this, but what
-#        should we do instead?  Silently leaving at z/d seems just as bad or
-#        maybe even worse.  Perhaps we could print a big warning about z/d
-#        and how we're moving to y/d in this case, but when I started thinking
-#        about the ramifications of doing that, I didn't know how to rule out
-#        that opening other weird edge and corner cases so I just punted.
+#        should we do instead?  It's not at all clear to me whether z/d or
+#        y/d or something else is a better resolution here, and other cases
+#        start getting really tricky, so I just picked one.
 
 test_setup_8e () {
 	test_create_repo 8e &&
@@ -2844,6 +2843,14 @@ test_expect_success '9f: Renamed directory that only contained immediate subdirs
 #   Commit A: priority/{alpha,bravo}/$more_files
 #   Commit B: goal/{a,b}/$more_files, goal/c
 #   Expected: priority/{alpha,bravo}/$more_files, priority/c
+# We currently fail this test because the directory renames we detect are
+#   goal/a/ -> priority/alpha/
+#   goal/b/ -> priority/bravo/
+# We do not detect
+#   goal/   -> priority/
+# because of no files found within goal/, and the fact that "a" != "alpha"
+# and "b" != "bravo".  But I'm not sure it's really a failure given that
+# viewpoint...
 
 test_setup_9g () {
 	test_create_repo 9g &&
@@ -2880,6 +2887,7 @@ test_setup_9g () {
 }
 
 test_expect_failure '9g: Renamed directory that only contained immediate subdirs, immediate subdirs renamed' '
+	test_setup_9g &&
 	(
 		cd 9g &&
 
@@ -3362,6 +3370,7 @@ test_setup_10e () {
 }
 
 test_expect_failure '10e: Does git complain about untracked file that is not really in the way?' '
+	test_setup_10e &&
 	(
 		cd 10e &&
 
@@ -4403,7 +4412,7 @@ test_expect_success '13b(info): messages for transitive rename with conflicted c
 #   Commit O: z/{b,c},   x/{d,e}
 #   Commit A: y/{b,c,d}, x/e
 #   Commit B: z/{b,c,d}, x/e
-#   Expected: y/{b,c,d}, with info or conflict messages for d (
+#   Expected: y/{b,c,d}, x/e, with info or conflict messages for d
 #             A: renamed x/d -> z/d; B: renamed z/ -> y/ AND renamed x/d to y/d
 #             One could argue A had partial knowledge of what was done with
 #             d and B had full knowledge, but that's a slippery slope as
diff --git a/t/t6044-merge-unrelated-index-changes.sh b/t/t6424-merge-unrelated-index-changes.sh
index 5e3779ebc9..5e3779ebc9 100755
--- a/t/t6044-merge-unrelated-index-changes.sh
+++ b/t/t6424-merge-unrelated-index-changes.sh
diff --git a/t/t6045-merge-rename-delete.sh b/t/t6425-merge-rename-delete.sh
index 5d33577d2f..f79d021590 100755
--- a/t/t6045-merge-rename-delete.sh
+++ b/t/t6425-merge-rename-delete.sh
@@ -17,7 +17,8 @@ test_expect_success 'rename/delete' '
 	git commit -m "delete" &&
 
 	test_must_fail git merge --strategy=recursive rename >output &&
-	test_i18ngrep "CONFLICT (rename/delete): A deleted in HEAD and renamed to B in rename. Version rename of B left in tree." output
+	test_i18ngrep "CONFLICT (rename/delete): A.* renamed .*to B.* in rename" output &&
+	test_i18ngrep "CONFLICT (rename/delete): A.*deleted in HEAD." output
 '
 
 test_done
diff --git a/t/t6046-merge-skip-unneeded-updates.sh b/t/t6426-merge-skip-unneeded-updates.sh
index 5a2d07e516..699813671c 100755
--- a/t/t6046-merge-skip-unneeded-updates.sh
+++ b/t/t6426-merge-skip-unneeded-updates.sh
@@ -374,7 +374,7 @@ test_expect_success '2c: Modify b & add c VS rename b->c' '
 		export GIT_MERGE_VERBOSITY &&
 		test_must_fail git merge -s recursive B^0 >out 2>err &&
 
-		test_i18ngrep "CONFLICT (rename/add): Rename b->c" out &&
+		test_i18ngrep "CONFLICT (.*/add):" out &&
 		test_must_be_empty err &&
 
 		# Make sure c WAS updated
diff --git a/t/t6047-diff3-conflict-markers.sh b/t/t6427-diff3-conflict-markers.sh
index f4655bb358..f4655bb358 100755
--- a/t/t6047-diff3-conflict-markers.sh
+++ b/t/t6427-diff3-conflict-markers.sh
diff --git a/t/t3030-merge-recursive.sh b/t/t6430-merge-recursive.sh
index d48d211a95..d48d211a95 100755
--- a/t/t3030-merge-recursive.sh
+++ b/t/t6430-merge-recursive.sh
diff --git a/t/t3031-merge-criscross.sh b/t/t6431-merge-criscross.sh
index 3824756a02..3824756a02 100755
--- a/t/t3031-merge-criscross.sh
+++ b/t/t6431-merge-criscross.sh
diff --git a/t/t3032-merge-recursive-space-options.sh b/t/t6432-merge-recursive-space-options.sh
index b56180ee4a..b56180ee4a 100755
--- a/t/t3032-merge-recursive-space-options.sh
+++ b/t/t6432-merge-recursive-space-options.sh
diff --git a/t/t3033-merge-toplevel.sh b/t/t6433-merge-toplevel.sh
index e29c284b9b..e29c284b9b 100755
--- a/t/t3033-merge-toplevel.sh
+++ b/t/t6433-merge-toplevel.sh
diff --git a/t/t3034-merge-recursive-rename-options.sh b/t/t6434-merge-recursive-rename-options.sh
index 3d9fae68c4..3d9fae68c4 100755
--- a/t/t3034-merge-recursive-rename-options.sh
+++ b/t/t6434-merge-recursive-rename-options.sh
diff --git a/t/t3035-merge-sparse.sh b/t/t6435-merge-sparse.sh
index 74562e1235..74562e1235 100755
--- a/t/t3035-merge-sparse.sh
+++ b/t/t6435-merge-sparse.sh
diff --git a/t/t7607-merge-overwrite.sh b/t/t6436-merge-overwrite.sh
index dd8ab7ede1..dd8ab7ede1 100755
--- a/t/t7607-merge-overwrite.sh
+++ b/t/t6436-merge-overwrite.sh
diff --git a/t/t7405-submodule-merge.sh b/t/t6437-submodule-merge.sh
index 6a1e5f8232..6a1e5f8232 100755
--- a/t/t7405-submodule-merge.sh
+++ b/t/t6437-submodule-merge.sh
diff --git a/t/t7613-merge-submodule.sh b/t/t6438-submodule-directory-file-conflicts.sh
index 04bf4be7d7..04bf4be7d7 100755
--- a/t/t7613-merge-submodule.sh
+++ b/t/t6438-submodule-directory-file-conflicts.sh
diff --git a/t/t7609-merge-co-error-msgs.sh b/t/t6439-merge-co-error-msgs.sh
index 5c8894d94f..5c8894d94f 100755
--- a/t/t7609-merge-co-error-msgs.sh
+++ b/t/t6439-merge-co-error-msgs.sh
diff --git a/t/t8003-blame-corner-cases.sh b/t/t8003-blame-corner-cases.sh
index b871dd4f86..ba8013b002 100755
--- a/t/t8003-blame-corner-cases.sh
+++ b/t/t8003-blame-corner-cases.sh
@@ -273,18 +273,14 @@ test_expect_success 'blame file with CRLF core.autocrlf=true' '
 	grep "A U Thor" actual
 '
 
-# Tests the splitting and merging of blame entries in blame_coalesce().
-# The output of blame is the same, regardless of whether blame_coalesce() runs
-# or not, so we'd likely only notice a problem if blame crashes or assigned
-# blame to the "splitting" commit ('SPLIT' below).
-test_expect_success 'blame coalesce' '
+test_expect_success 'setup coalesce tests' '
 	cat >giraffe <<-\EOF &&
 	ABC
 	DEF
 	EOF
 	git add giraffe &&
 	git commit -m "original file" &&
-	oid=$(git rev-parse HEAD) &&
+	orig=$(git rev-parse HEAD) &&
 
 	cat >giraffe <<-\EOF &&
 	ABC
@@ -293,6 +289,7 @@ test_expect_success 'blame coalesce' '
 	EOF
 	git add giraffe &&
 	git commit -m "interior SPLIT line" &&
+	split=$(git rev-parse HEAD) &&
 
 	cat >giraffe <<-\EOF &&
 	ABC
@@ -300,12 +297,25 @@ test_expect_success 'blame coalesce' '
 	EOF
 	git add giraffe &&
 	git commit -m "same contents as original" &&
+	final=$(git rev-parse HEAD)
+'
+
+test_expect_success 'blame coalesce' '
+	cat >expect <<-EOF &&
+	$orig 1 1 2
+	$orig 2 2
+	EOF
+	git blame --porcelain $final giraffe >actual.raw &&
+	grep "^$orig" actual.raw >actual &&
+	test_cmp expect actual
+'
 
+test_expect_success 'blame does not coalesce non-adjacent result lines' '
 	cat >expect <<-EOF &&
-	$oid 1) ABC
-	$oid 2) DEF
+	$orig 1) ABC
+	$orig 3) DEF
 	EOF
-	git -c core.abbrev=$(test_oid hexsz) blame -s giraffe >actual &&
+	git blame --no-abbrev -s -L1,1 -L3,3 $split giraffe >actual &&
 	test_cmp expect actual
 '
 
diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
index 3d68570450..a08f72596a 100755
--- a/t/t9001-send-email.sh
+++ b/t/t9001-send-email.sh
@@ -2142,4 +2142,33 @@ test_expect_success $PREREQ 'test that send-email works outside a repo' '
 		"$(pwd)/0001-add-master.patch"
 '
 
+test_expect_success $PREREQ 'test that sendmail config is rejected' '
+	test_config sendmail.program sendmail &&
+	test_must_fail git send-email \
+		--from="Example <nobody@example.com>" \
+		--to=nobody@example.com \
+		--smtp-server="$(pwd)/fake.sendmail" \
+		HEAD^ 2>err &&
+	test_i18ngrep "found configuration options for '"'"sendmail"'"'" err
+'
+
+test_expect_success $PREREQ 'test that sendmail config rejection is specific' '
+	test_config resendmail.program sendmail &&
+	git send-email \
+		--from="Example <nobody@example.com>" \
+		--to=nobody@example.com \
+		--smtp-server="$(pwd)/fake.sendmail" \
+		HEAD^
+'
+
+test_expect_success $PREREQ 'test forbidSendmailVariables behavior override' '
+	test_config sendmail.program sendmail &&
+	test_config sendemail.forbidSendmailVariables false &&
+	git send-email \
+		--from="Example <nobody@example.com>" \
+		--to=nobody@example.com \
+		--smtp-server="$(pwd)/fake.sendmail" \
+		HEAD^
+'
+
 test_done
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 596c549cdd..6a8e194a99 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -952,7 +952,13 @@ test_expect_code () {
 # - not all diff versions understand "-u"
 
 test_cmp() {
-	eval "$GIT_TEST_CMP" '"$@"'
+	test $# -eq 2 || BUG "test_cmp requires two arguments"
+	if ! eval "$GIT_TEST_CMP" '"$@"'
+	then
+		test "x$1" = x- || test -e "$1" || BUG "test_cmp '$1' missing"
+		test "x$2" = x- || test -e "$2" || BUG "test_cmp '$2' missing"
+		return 1
+	fi
 }
 
 # Check that the given config key has the expected value.
@@ -981,7 +987,13 @@ test_cmp_config() {
 # test_cmp_bin - helper to compare binary files
 
 test_cmp_bin() {
-	cmp "$@"
+	test $# -eq 2 || BUG "test_cmp_bin requires two arguments"
+	if ! cmp "$@"
+	then
+		test "x$1" = x- || test -e "$1" || BUG "test_cmp_bin '$1' missing"
+		test "x$2" = x- || test -e "$2" || BUG "test_cmp_bin '$2' missing"
+		return 1
+	fi
 }
 
 # Use this instead of test_cmp to compare files that contain expected and
diff --git a/upload-pack.c b/upload-pack.c
index 80ad9a38d8..46a5cac0a9 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -739,7 +739,6 @@ static int has_unreachable(struct object_array *src, enum allow_uor allow_uor)
 	return 0;
 
 error:
-	sigchain_pop(SIGPIPE);
 	if (cmd.out >= 0)
 		close(cmd.out);
 	return 1;
diff --git a/userdiff.c b/userdiff.c
index 1df884ef0b..fde02f225b 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -46,10 +46,14 @@ PATTERNS("elixir",
 	 /* Not real operators, but should be grouped */
 	 "|:?%[A-Za-z0-9_.]\\{\\}?"),
 IPATTERN("fortran",
+	 /* Don't match comment lines */
 	 "!^([C*]|[ \t]*!)\n"
+	 /* Don't match 'module procedure' lines */
 	 "!^[ \t]*MODULE[ \t]+PROCEDURE[ \t]\n"
+	 /* Program, module, block data */
 	 "^[ \t]*((END[ \t]+)?(PROGRAM|MODULE|BLOCK[ \t]+DATA"
-		"|([^'\" \t]+[ \t]+)*(SUBROUTINE|FUNCTION))[ \t]+[A-Z].*)$",
+		/* Subroutines and functions */
+		"|([^!'\" \t]+[ \t]+)*(SUBROUTINE|FUNCTION))[ \t]+[A-Z].*)$",
 	 /* -- */
 	 "[a-zA-Z][a-zA-Z0-9_]*"
 	 "|\\.([Ee][Qq]|[Nn][Ee]|[Gg][TtEe]|[Ll][TtEe]|[Tt][Rr][Uu][Ee]|[Ff][Aa][Ll][Ss][Ee]|[Aa][Nn][Dd]|[Oo][Rr]|[Nn]?[Ee][Qq][Vv]|[Nn][Oo][Tt])\\."