21 files changed, 332 insertions, 46 deletions
diff --git a/Documentation/RelNotes/2.8.0.txt b/Documentation/RelNotes/2.8.0.txt
index 5ec39bc300..25079710fa 100644
--- a/Documentation/RelNotes/2.8.0.txt
+++ b/Documentation/RelNotes/2.8.0.txt
@@ -34,7 +34,7 @@ UI, Workflows & Features
    have a place to store the updated notes tree, iow, a ref).
 
  * "git grep" by default does not fall back to its "--no-index"
-   behaviour outside a directory under Git's control (otherwise the
+   behavior outside a directory under Git's control (otherwise the
    user may by mistake end up running a huge recursive search); with a
    new configuration (set in $HOME/.gitconfig--by definition this
    cannot be set in the config file per project), this safety can be
@@ -55,7 +55,7 @@ UI, Workflows & Features
 
  * Many commands that read files that are expected to contain text
    that is generated (or can be edited) by the end user to control
-   their behaviour (e.g. "git grep -f <filename>") have been updated
+   their behavior (e.g. "git grep -f <filename>") have been updated
    to be more tolerant to lines that are terminated with CRLF (they
    used to treat such a line to contain payload that ends with CR,
    which is usually not what the users expect).
@@ -187,7 +187,7 @@ Performance, Internal Implementation, Development Support etc.
    with expectations that are not satisfiable on Git for Windows.
 
  * Some calls to strcpy(3) triggers a false warning from static
-   analysers that are less intelligent than humans, and reducing the
+   analyzers that are less intelligent than humans, and reducing the
    number of these false hits helps us notice real issues.  A few
    calls to strcpy(3) in a couple of protrams that are already safe
    has been rewritten to avoid false warnings.
@@ -281,7 +281,7 @@ notes for details).
  * "git send-email" was confused by escaped quotes stored in the alias
    files saved by "mutt", which has been corrected.
 
- * A few unportable C construct have been spotted by clang compiler
+ * A few non-portable C construct have been spotted by clang compiler
    and have been fixed.
 
  * The documentation has been updated to hint the connection between
@@ -349,10 +349,10 @@ notes for details).
  * "git worktree" had a broken code that attempted to auto-fix
    possible inconsistency that results from end-users moving a
    worktree to different places without telling Git (the original
-   repository needs to maintain backpointers to its worktrees, but
-   "mv" run by end-users who are not familiar with that fact will
-   obviously not adjust them), which actually made things worse
-   when triggered.
+   repository needs to maintain back-pointers to its worktrees,
+   but "mv" run by end-users who are not familiar with that fact
+   will obviously not adjust them), which actually made things
+   worse when triggered.
 
  * The low-level merge machinery has been taught to use CRLF line
    termination when inserting conflict markers to merged contents that
diff --git a/Documentation/RelNotes/2.8.1.txt b/Documentation/RelNotes/2.8.1.txt
new file mode 100644
index 0000000000..ef6d80b008
--- /dev/null
+++ b/Documentation/RelNotes/2.8.1.txt
@@ -0,0 +1,9 @@
+Git v2.8.1 Release Notes
+========================
+
+Fixes since v2.8
+----------------
+
+ * "make rpmbuild" target was broken as its input, git.spec.in, was
+   not updated to match a file it describes that has been renamed
+   recently.  This has been fixed.
diff --git a/Documentation/RelNotes/2.9.0.txt b/Documentation/RelNotes/2.9.0.txt
new file mode 100644
index 0000000000..9165443f54
--- /dev/null
+++ b/Documentation/RelNotes/2.9.0.txt
@@ -0,0 +1,157 @@
+Git 2.9 Release Notes
+=====================
+
+Backward compatibility note
+---------------------------
+
+The end-user facing Porcelain level commands in the "git diff" and
+"git log" by default enables the rename detection; you can still use
+"diff.renames" configuration variable to disable this.
+
+Merging two branches that have no common ancestor with "git merge" is
+by default forbidden now to prevent creating such an unusual merge by
+mistake.
+
+
+Updates since v2.8
+------------------
+
+UI, Workflows & Features
+
+ * The end-user facing Porcelain level commands like "diff" and "log"
+   now enables the rename detection by default.
+
+ * The credential.helper configuration variable is cumulative and
+   there is no good way to override it from the command line.  As
+   a special case, giving an empty string as its value now serves
+   as the signal to clear the values specified in various files.
+
+ * A new "interactive.diffFilter" configuration can be used to
+   customize the diff shown in "git add -i" session.
+
+ * "git p4" now allows P4 author names to be mapped to Git author
+   names.
+
+ * "git rebase -x" can be used without passing "-i" option.
+
+ * "git -c credential.<var>=<value> submodule" can now be used to
+   propagate configuration variables related to credential helper
+   down to the submodules.
+
+ * "git tag" can create an annotated tag without explicitly given an
+   "-a" (or "-s") option (i.e. when a tag message is given).  A new
+   configuration variable, tag.forceSignAnnotated, can be used to tell
+   the command to create signed tag in such a situation.
+
+ * "git merge" used to allow merging two branches that have no common
+   base by default, which led to a brand new history of an existing
+   project created and then get pulled by an unsuspecting maintainer,
+   which allowed an unnecessary parallel history merged into the
+   existing project.  The command has been taught not to allow this by
+   default, with an escape hatch "--allow-unrelated-histories" option
+   to be used in a rare event that merges histories of two projects
+   that started their lives independently.
+   (merge e379fdf jc/merge-refuse-new-root later to maint).
+
+ * "git apply -v" learned to report paths in the patch that were
+   skipped via --include/--exclude mechanism or being outside the
+   current working directory.
+   (merge 3f57944 nd/apply-report-skip later to maint).
+
+
+Performance, Internal Implementation, Development Support etc.
+
+ * The embedded args argv-array in the child process is used to build
+   the command line to run pack-objects instead of using a separate
+   array of strings.
+   (merge 65a3629 mp/upload-pack-use-embedded-args later to maint).
+
+ * A test for tags has been restructured so that more parts of it can
+   easily be run on a platform without a working GnuPG.
+
+ * The startup_info data, which records if we are working inside a
+   repository (among other things), are now uniformly available to Git
+   subcommand implementations, and Git avoids attempting to touch
+   references when we are not in a repository.
+   (merge 11e6b3f jk/startup-info later to maint).
+
+ * The command line argument parser for "receive-pack" has been
+   rewritten to use parse-options.
+
+ * A major part of "git submodule update" has been ported to C to take
+   advantage of the recently added framework to run download tasks in
+   parallel.
+
+ * Rename bunch of tests on "git clone" for better organization.
+   (merge 8fbb03a sb/clone-t57-t56 later to maint).
+
+ * The tests that involve running httpd leaked the system-wide
+   configuration in /etc/gitconfig to the tested environment.
+   (merge 1fad503 jk/test-httpd-config-nosystem later to maint).
+
+ * Build updates for MSVC.
+   (merge 0ef60af ss/msvc later to maint).
+
+Also contains various documentation updates and code clean-ups.
+
+
+Fixes since v2.8
+----------------
+
+Unless otherwise noted, all the fixes since v2.8 in the maintenance
+track are contained in this release (see the maintenance releases'
+notes for details).
+
+ * "git config --get-urlmatch", unlike other variants of the "git
+   config --get" family, did not signal error with its exit status
+   when there was no matching configuration.
+   (merge 24990b2 jk/config-get-urlmatch later to maint).
+
+ * The "--local-env-vars" and "--resolve-git-dir" options of "git
+   rev-parse" failed to work outside a repository when the command's
+   option parsing was rewritten in 1.8.5 era.
+   (merge fc7d47f jk/rev-parse-local-env-vars later to maint).
+
+ * "git index-pack --keep[=<msg>] pack-$name.pack" simply did not work.
+   (merge 0e94242 jc/maint-index-pack-keep later to maint).
+
+ * Fetching of history by naming a commit object name directly didn't
+   work across remote-curl transport.
+   (merge 754ecb1 gf/fetch-pack-direct-object-fetch later to maint).
+
+ * A small memory leak in an error codepath has been plugged in xdiff
+   code.
+   (merge 87f1625 rj/xdiff-prepare-plug-leak-on-error-codepath later to maint).
+
+ * strbuf_getwholeline() did not NUL-terminate the buffer on certain
+   corner cases in its error codepath.
+   (merge b709043 jk/getwholeline-getdelim-empty later to maint).
+
+ * "git mergetool" did not work well with conflicts that both sides
+   deleted.
+   (merge a298604 da/mergetool-delete-delete-conflict later to maint).
+
+ * "git send-email" had trouble parsing alias file in mailrc format
+   when lines in it had trailing whitespaces on them.
+   (merge a277d1e jk/send-email-rtrim-mailrc-alias later to maint).
+
+ * When "git merge --squash" stopped due to conflict, the concluding
+   "git commit" failed to read in the SQUASH_MSG that shows the log
+   messages from all the squashed commits.
+   (merge b64c1e0 ss/commit-squash-msg later to maint).
+
+ * "git merge FETCH_HEAD" dereferenced NULL pointer when merging
+   nothing into an unborn history (which is arguably unusual usage,
+   which perhaps was the reason why nobody noticed it).
+   (merge b84e65d jv/merge-nothing-into-void later to maint).
+
+ * Other minor clean-ups and documentation updates
+   (merge aed7480 mm/lockfile-error-message later to maint).
+   (merge bfee614 jc/index-pack later to maint).
+   (merge f870899 ss/exc-flag-is-a-collection-of-bits later to maint).
+   (merge dde7891 pb/t7502-drop-dup later to maint).
+   (merge 3bd1b51 cc/doc-recommend-performance-trace-to-file later to maint).
+   (merge 7d5e9c9 jk/credential-cache-comment-exit later to maint).
+   (merge 16a86d4 nd/apply-doc later to maint).
+   (merge c3f6b85 pb/opt-cmdmode-doc later to maint).
+   (merge 30211fb oa/doc-diff-check later to maint).
diff --git a/Documentation/config.txt b/Documentation/config.txt
index 2cd6bdd7d2..42d2b50477 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1113,8 +1113,9 @@ commit.template::
 credential.helper::
 	Specify an external helper to be called when a username or
 	password credential is needed; the helper may consult external
-	storage to avoid prompting the user for the credentials. See
-	linkgit:gitcredentials[7] for details.
+	storage to avoid prompting the user for the credentials. Note
+	that multiple helpers may be defined. See linkgit:gitcredentials[7]
+	for details.
 
 credential.useHttpPath::
 	When acquiring credentials, consider the "path" component of an http
@@ -1886,6 +1887,14 @@ interactive.singleKey::
 	setting is silently ignored if portable keystroke input
 	is not available; requires the Perl module Term::ReadKey.
 
+interactive.diffFilter::
+	When an interactive command (such as `git add --patch`) shows
+	a colorized diff, git will pipe the diff through the shell
+	command defined by this configuration variable. The command may
+	mark up the diff further for human consumption, provided that it
+	retains a one-to-one correspondence with the lines in the
+	original diff. Defaults to disabled (no filtering).
+
 log.abbrevCommit::
 	If true, makes linkgit:git-log[1], linkgit:git-show[1], and
 	linkgit:git-whatchanged[1] assume `--abbrev-commit`. You may
@@ -2729,6 +2738,17 @@ submodule.<name>.ignore::
 	"--ignore-submodules" option. The 'git submodule' commands are not
 	affected by this setting.
 
+submodule.fetchJobs::
+	Specifies how many submodules are fetched/cloned at the same time.
+	A positive integer allows up to that number of submodules fetched
+	in parallel. A value of 0 will give some reasonable default.
+	If unset, it defaults to 1.
+
+tag.forceSignAnnotated::
+	A boolean to specify whether annotated tags created should be GPG signed.
+	If `--annotate` is specified on the command line, it takes
+	precedence over this option.
+
 tag.sort::
 	This variable controls the sort ordering of tags when displayed by
 	linkgit:git-tag[1]. Without the "--sort=<value>" option provided, the
diff --git a/Documentation/diff-config.txt b/Documentation/diff-config.txt
index 6eaa45271c..edba56522b 100644
--- a/Documentation/diff-config.txt
+++ b/Documentation/diff-config.txt
@@ -108,9 +108,13 @@ diff.renameLimit::
 	detection; equivalent to the 'git diff' option '-l'.
 
 diff.renames::
-	Tells Git to detect renames.  If set to any boolean value, it
-	will enable basic rename detection.  If set to "copies" or
-	"copy", it will detect copies, as well.
+	Whether and how Git detects renames.  If set to "false",
+	rename detection is disabled. If set to "true", basic rename
+	detection is enabled.  If set to "copies" or "copy", Git will
+	detect copies, as well.  Defaults to true.  Note that this
+	affects only 'git diff' Porcelain like linkgit:git-diff[1] and
+	linkgit:git-log[1], and not lower level commands such as
+	linkgit:git-diff-files[1].
 
 diff.suppressBlankEmpty::
 	A boolean to inhibit the standard behavior of printing a space
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 306b7e3604..32f48ed647 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -286,8 +286,8 @@ endif::git-format-patch[]
 
 ifndef::git-format-patch[]
 --check::
-	Warn if changes introduce whitespace errors.  What are
-	considered whitespace errors is controlled by `core.whitespace`
+	Warn if changes introduce conflict markers or whitespace errors.
+	What are considered whitespace errors is controlled by `core.whitespace`
 	configuration.  By default, trailing whitespaces (including
 	lines that solely consist of whitespaces) and a space character
 	that is immediately followed by a tab character inside the
diff --git a/Documentation/git-apply.txt b/Documentation/git-apply.txt
index d9ed6a1a4e..8ddb207409 100644
--- a/Documentation/git-apply.txt
+++ b/Documentation/git-apply.txt
@@ -13,7 +13,7 @@ SYNOPSIS
 	  [--apply] [--no-add] [--build-fake-ancestor=<file>] [-R | --reverse]
 	  [--allow-binary-replacement | --binary] [--reject] [-z]
 	  [-p<n>] [-C<n>] [--inaccurate-eof] [--recount] [--cached]
-	  [--ignore-space-change | --ignore-whitespace ]
+	  [--ignore-space-change | --ignore-whitespace]
 	  [--whitespace=(nowarn|warn|fix|error|error-all)]
 	  [--exclude=<path>] [--include=<path>] [--directory=<root>]
 	  [--verbose] [--unsafe-paths] [<patch>...]
@@ -21,6 +21,8 @@ SYNOPSIS
 DESCRIPTION
 -----------
 Reads the supplied diff output (i.e. "a patch") and applies it to files.
+When running from a subdirectory in a repository, patched paths
+outside the directory are ignored.
 With the `--index` option the patch is also applied to the index, and
 with the `--cached` option the patch is only applied to the index.
 Without these options, the command applies the patch only to files,
diff --git a/Documentation/git-clone.txt b/Documentation/git-clone.txt
index b7c467a001..45d74be297 100644
--- a/Documentation/git-clone.txt
+++ b/Documentation/git-clone.txt
@@ -14,7 +14,7 @@ SYNOPSIS
 	  [-o <name>] [-b <name>] [-u <upload-pack>] [--reference <repository>]
 	  [--dissociate] [--separate-git-dir <git dir>]
 	  [--depth <depth>] [--[no-]single-branch]
-	  [--recursive | --recurse-submodules] [--] <repository>
+	  [--recursive | --recurse-submodules] [--jobs <n>] [--] <repository>
 	  [<directory>]
 
 DESCRIPTION
@@ -219,6 +219,10 @@ objects from the source repository into a pack in the cloned repository.
 	The result is Git repository can be separated from working
 	tree.
 
+-j <n>::
+--jobs <n>::
+	The number of submodules fetched at the same time.
+	Defaults to the `submodule.fetchJobs` option.
 
 <repository>::
 	The (possibly remote) repository to clone from.  See the
diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt
index 153b2d89b5..6fc08e3d89 100644
--- a/Documentation/git-config.txt
+++ b/Documentation/git-config.txt
@@ -58,13 +58,13 @@ that location (you can say '--local' but that is the default).
 This command will fail with non-zero status upon error.  Some exit
 codes are:
 
-. The config file is invalid (ret=3),
-. can not write to the config file (ret=4),
-. no section or name was provided (ret=2),
-. the section or key is invalid (ret=1),
-. you try to unset an option which does not exist (ret=5),
-. you try to unset/set an option for which multiple lines match (ret=5), or
-. you try to use an invalid regexp (ret=6).
+- The config file is invalid (ret=3),
+- can not write to the config file (ret=4),
+- no section or name was provided (ret=2),
+- the section or key is invalid (ret=1),
+- you try to unset an option which does not exist (ret=5),
+- you try to unset/set an option for which multiple lines match (ret=5), or
+- you try to use an invalid regexp (ret=6).
 
 On success, the command returns the exit code 0.
 
@@ -86,8 +86,7 @@ OPTIONS
 	found and the last value if multiple key values were found.
 
 --get-all::
-	Like get, but does not fail if the number of values for the key
-	is not exactly one.
+	Like get, but returns all values for a multi-valued key.
 
 --get-regexp::
 	Like --get-all, but interprets the name as a regular expression and
@@ -102,7 +101,7 @@ OPTIONS
 	given URL is returned (if no such key exists, the value for
 	section.key is used as a fallback).  When given just the
 	section as name, do so for all the keys in the section and
-	list them.
+	list them.  Returns error code 1 if no value is found.
 
 --global::
 	For writing options: write to global `~/.gitconfig` file
diff --git a/Documentation/git-fetch-pack.txt b/Documentation/git-fetch-pack.txt
index 8680f45f8d..239623cc24 100644
--- a/Documentation/git-fetch-pack.txt
+++ b/Documentation/git-fetch-pack.txt
@@ -104,6 +104,10 @@ be in a separate packet, and the list must end with a flush packet.
 	The remote heads to update from. This is relative to
 	$GIT_DIR (e.g. "HEAD", "refs/heads/master").  When
 	unspecified, update from all heads the remote side has.
++
+If the remote has enabled the options `uploadpack.allowTipSHA1InWant` or
+`uploadpack.allowReachableSHA1InWant`, they may alternatively be 40-hex
+sha1s present on the remote.
 
 SEE ALSO
 --------
diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 012e8f9a08..c52578bb87 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -76,7 +76,7 @@ OPTIONS
 	specified commit (HEAD if not specified).
 
 --contains [<object>]::
-	Only list tags which contain the specified commit (HEAD if not
+	Only list refs which contain the specified commit (HEAD if not
 	specified).
 
 FIELD NAMES
diff --git a/Documentation/git-merge.txt b/Documentation/git-merge.txt
index 07f7295ec8..689aa4c57c 100644
--- a/Documentation/git-merge.txt
+++ b/Documentation/git-merge.txt
@@ -98,6 +98,19 @@ commit or stash your changes before running 'git merge'.
 'git merge --abort' is equivalent to 'git reset --merge' when
 `MERGE_HEAD` is present.
 
+--allow-unrelated-histories::
+	By default, `git merge` command refuses to merge histories
+	that do not share a common ancestor.  This option can be
+	used to override this safety when merging histories of two
+	projects that started their lives independently.  As that is
+	a very rare occasion, no configuration variable to enable
+	this by default exists and will not be added, and the list
+	of options at the top of this documentation does not mention
+	this option.  Also `git pull` does not pass this option down
+	to `git merge` (instead, you `git fetch` first, examine what
+	you will be merging and then `git merge` locally with this
+	option).
+
 <commit>...::
 	Commits, usually other branch heads, to merge into our branch.
 	Specifying more than one commit will create a merge with
diff --git a/Documentation/git-p4.txt b/Documentation/git-p4.txt
index 738cfde10c..88ba42b455 100644
--- a/Documentation/git-p4.txt
+++ b/Documentation/git-p4.txt
@@ -515,20 +515,18 @@ git-p4.pathEncoding::
 	Git expects paths encoded as UTF-8. Use this config to tell git-p4
 	what encoding Perforce had used for the paths. This encoding is used
 	to transcode the paths to UTF-8. As an example, Perforce on Windows
-	often uses “cp1252” to encode path names.
+	often uses "cp1252" to encode path names.
 
 git-p4.largeFileSystem::
 	Specify the system that is used for large (binary) files. Please note
 	that large file systems do not support the 'git p4 submit' command.
-	Only Git LFS [1] is implemented right now. Download
-	and install the Git LFS command line extension to use this option
-	and configure it like this:
+	Only Git LFS is implemented right now (see https://git-lfs.github.com/
+	for more information). Download and install the Git LFS command line
+	extension to use this option and configure it like this:
 +
 -------------
 git config       git-p4.largeFileSystem GitLFS
 -------------
-+
-	[1] https://git-lfs.github.com/
 
 git-p4.largeFileExtensions::
 	All files matching a file extension in the list will be processed
@@ -553,6 +551,17 @@ git-p4.keepEmptyCommits::
 	A changelist that contains only excluded files will be imported
 	as an empty commit if this boolean option is set to true.
 
+git-p4.mapUser::
+	Map a P4 user to a name and email address in Git. Use a string
+	with the following format to create a mapping:
++
+-------------
+git config --add git-p4.mapUser "p4user = First Last <mail@address.com>"
+-------------
++
+A mapping will override any user information from P4. Mappings for
+multiple P4 user can be defined.
+
 Submit variables
 ~~~~~~~~~~~~~~~~
 git-p4.detectRenames::
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 6ed610a031..0387b40e0a 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -391,9 +391,6 @@ idea unless you know what you are doing (see BUGS below).
 	final history. <cmd> will be interpreted as one or more shell
 	commands.
 +
-This option can only be used with the `--interactive` option
-(see INTERACTIVE MODE below).
-+
 You may execute several commands by either using one instance of `--exec`
 with several commands:
 +
@@ -406,6 +403,9 @@ or by giving more than one `--exec`:
 If `--autosquash` is used, "exec" lines will not be appended for
 the intermediate commits, and will only appear at the end of each
 squash/fixup series.
++
+This uses the `--interactive` machinery internally, but it can be run
+without an explicit `--interactive`.
 
 --root::
 	Rebase all commits reachable from <branch>, instead of
diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index 1572f058f5..13adebf7b7 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -16,7 +16,7 @@ SYNOPSIS
 'git submodule' [--quiet] deinit [-f|--force] [--] <path>...
 'git submodule' [--quiet] update [--init] [--remote] [-N|--no-fetch]
 	      [-f|--force] [--rebase|--merge] [--reference <repository>]
-	      [--depth <depth>] [--recursive] [--] [<path>...]
+	      [--depth <depth>] [--recursive] [--jobs <n>] [--] [<path>...]
 'git submodule' [--quiet] summary [--cached|--files] [(-n|--summary-limit) <n>]
 	      [commit] [--] [<path>...]
 'git submodule' [--quiet] foreach [--recursive] <command>
@@ -377,6 +377,11 @@ for linkgit:git-clone[1]'s `--reference` and `--shared` options carefully.
 	clone with a history truncated to the specified number of revisions.
 	See linkgit:git-clone[1]
 
+-j <n>::
+--jobs <n>::
+	This option is only valid for the update command.
+	Clone new submodules in parallel with as many jobs.
+	Defaults to the `submodule.fetchJobs` option.
 
 <path>...::
 	Paths to submodule(s). When specified this will restrict the command
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index 62c76c1c89..c62234538b 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -9,7 +9,7 @@ git-worktree - Manage multiple working trees
 SYNOPSIS
 --------
 [verse]
-'git worktree add' [-f] [--detach] [-b <new-branch>] <path> [<branch>]
+'git worktree add' [-f] [--detach] [--checkout] [-b <new-branch>] <path> [<branch>]
 'git worktree prune' [-n] [-v] [--expire <expire>]
 'git worktree list' [--porcelain]
 
@@ -87,6 +87,12 @@ OPTIONS
 	With `add`, detach HEAD in the new working tree. See "DETACHED HEAD"
 	in linkgit:git-checkout[1].
 
+--[no-]checkout::
+	By default, `add` checks out `<branch>`, however, `--no-checkout` can
+	be used to suppress checkout in order to make customizations,
+	such as configuring sparse-checkout. See "Sparse checkout"
+	in linkgit:git-read-tree[1].
+
 -n::
 --dry-run::
 	With `prune`, do not remove anything; just report what it would
diff --git a/Documentation/git.txt b/Documentation/git.txt
index a9120a8779..8afe349781 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -43,6 +43,12 @@ unreleased) version of Git, that is available from the 'master'
 branch of the `git.git` repository.
 Documentation for older releases are available here:
 
+* link:v2.8.1/git.html[documentation for release 2.8.1]
+
+* release notes for
+  link:RelNotes/2.8.1.txt[2.8.1].
+  link:RelNotes/2.8.0.txt[2.8].
+
 * link:v2.7.3/git.html[documentation for release 2.7.3]
 
 * release notes for
diff --git a/Documentation/gitcredentials.txt b/Documentation/gitcredentials.txt
index 1c75be0803..f3a75d1ce1 100644
--- a/Documentation/gitcredentials.txt
+++ b/Documentation/gitcredentials.txt
@@ -106,6 +106,11 @@ variable, each helper will be tried in turn, and may provide a username,
 password, or nothing. Once Git has acquired both a username and a
 password, no more helpers will be tried.
 
+If `credential.helper` is configured to the empty string, this resets
+the helper list to empty (so you may override a helper set by a
+lower-priority config file by configuring the empty-string helper,
+followed by whatever set of helpers you would like).
+
 
 CREDENTIAL CONTEXTS
 -------------------
diff --git a/Documentation/technical/api-config.txt b/Documentation/technical/api-config.txt
index 0d8b99b368..20741f345e 100644
--- a/Documentation/technical/api-config.txt
+++ b/Documentation/technical/api-config.txt
@@ -63,13 +63,6 @@ parse for configuration, rather than looking in the usual files. Regular
 Specify whether include directives should be followed in parsed files.
 Regular `git_config` defaults to `1`.
 
-There is a special version of `git_config` called `git_config_early`.
-This version takes an additional parameter to specify the repository
-config, instead of having it looked up via `git_path`. This is useful
-early in a Git program before the repository has been found. Unless
-you're working with early setup code, you probably don't want to use
-this.
-
 Reading Specific Files
 ----------------------
 
diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt
index 5f0757dcc9..695bd4bf43 100644
--- a/Documentation/technical/api-parse-options.txt
+++ b/Documentation/technical/api-parse-options.txt
@@ -231,6 +231,13 @@ There are some macros to easily define options:
 	pass the command-line option, which can be specified multiple times,
 	to another command.
 
+`OPT_CMDMODE(short, long, &int_var, description, enum_val)`::
+	Define an "operation mode" option, only one of which in the same
+	group of "operating mode" options that share the same `int_var`
+	can be given by the user. `enum_val` is set to `int_var` when the
+	option is used, but an error is reported if other "operating mode"
+	option has already set its value to the same `int_var`.
+
 
 The last element of the array must be `OPT_END()`.
 
diff --git a/Documentation/technical/api-trace.txt b/Documentation/technical/api-trace.txt
index 097a651d96..389ae16d15 100644
--- a/Documentation/technical/api-trace.txt
+++ b/Documentation/technical/api-trace.txt
@@ -95,3 +95,46 @@ for (;;) {
 }
 trace_performance(t, "frotz");
 ------------
+
+Bugs & Caveats
+--------------
+
+GIT_TRACE_* environment variables can be used to tell Git to show
+trace output to its standard error stream. Git can often spawn a pager
+internally to run its subcommand and send its standard output and
+standard error to it.
+
+Because GIT_TRACE_PERFORMANCE trace is generated only at the very end
+of the program with atexit(), which happens after the pager exits, it
+would not work well if you send its log to the standard error output
+and let Git spawn the pager at the same time.
+
+As a work around, you can for example use '--no-pager', or set
+GIT_TRACE_PERFORMANCE to another file descriptor which is redirected
+to stderr, or set GIT_TRACE_PERFORMANCE to a file specified by its
+absolute path.
+
+For example instead of the following command which by default may not
+print any performance information:
+
+------------
+GIT_TRACE_PERFORMANCE=2 git log -1
+------------
+
+you may want to use:
+
+------------
+GIT_TRACE_PERFORMANCE=2 git --no-pager log -1
+------------
+
+or:
+
+------------
+GIT_TRACE_PERFORMANCE=3 3>&2 git log -1
+------------
+
+or:
+
+------------
+GIT_TRACE_PERFORMANCE=/path/to/log/file git log -1
+------------