Merge branch 'jc/merge' into next

* jc/merge:
  git-merge knows some strategies want to skip trivial merges
  generate-cmdlist: style cleanups.
  Add missing semicolon to sed command.
  unpack_delta_entry(): reduce memory footprint.
  git.el: Added a function to diff against the other heads in a merge.
  git.el: Get the default user name and email from the repository config.
  git.el: More robust handling of subprocess errors when returning strings.

4 files changed, 90 insertions, 56 deletions

diff --git a/contrib/emacs/git.el b/contrib/emacs/git.el
index 5135e361be..ebd00ef9c4 100644
--- a/contrib/emacs/git.el
+++ b/contrib/emacs/git.el
@@ -59,14 +59,14 @@
 
 (defcustom git-committer-name nil
   "User name to use for commits.
-The default is to fall back to `add-log-full-name' and then `user-full-name'."
+The default is to fall back to the repository config, then to `add-log-full-name' and then to `user-full-name'."
   :group 'git
   :type '(choice (const :tag "Default" nil)
                  (string :tag "Name")))
 
 (defcustom git-committer-email nil
   "Email address to use for commits.
-The default is to fall back to `add-log-mailing-address' and then `user-mail-address'."
+The default is to fall back to the git repository config, then to `add-log-mailing-address' and then to `user-mail-address'."
   :group 'git
   :type '(choice (const :tag "Default" nil)
                  (string :tag "Email")))
@@ -148,6 +148,12 @@ The default is to fall back to `add-log-mailing-address' and then `user-mail-add
              (append (git-get-env-strings env) (list "git") args))
     (apply #'call-process "git" nil buffer nil args)))
 
+(defun git-call-process-env-string (env &rest args)
+  "Wrapper for call-process that sets environment strings, and returns the process output as a string."
+  (with-temp-buffer
+    (and (eq 0 (apply #' git-call-process-env t env args))
+         (buffer-string))))
+
 (defun git-run-process-region (buffer start end program args)
   "Run a git process with a buffer region as input."
   (let ((output-buffer (current-buffer))
@@ -189,13 +195,15 @@ The default is to fall back to `add-log-mailing-address' and then `user-mail-add
 
 (defun git-get-string-sha1 (string)
   "Read a SHA1 from the specified string."
-  (let ((pos (string-match "[0-9a-f]\\{40\\}" string)))
-    (and pos (substring string pos (match-end 0)))))
+  (and string
+       (string-match "[0-9a-f]\\{40\\}" string)
+       (match-string 0 string)))
 
 (defun git-get-committer-name ()
   "Return the name to use as GIT_COMMITTER_NAME."
   ; copied from log-edit
   (or git-committer-name
+      (git-repo-config "user.name")
       (and (boundp 'add-log-full-name) add-log-full-name)
       (and (fboundp 'user-full-name) (user-full-name))
       (and (boundp 'user-full-name) user-full-name)))
@@ -204,6 +212,7 @@ The default is to fall back to `add-log-mailing-address' and then `user-mail-add
   "Return the email address to use as GIT_COMMITTER_EMAIL."
   ; copied from log-edit
   (or git-committer-email
+      (git-repo-config "user.email")
       (and (boundp 'add-log-mailing-address) add-log-mailing-address)
       (and (fboundp 'user-mail-address) (user-mail-address))
       (and (boundp 'user-mail-address) user-mail-address)))
@@ -259,18 +268,17 @@ The default is to fall back to `add-log-mailing-address' and then `user-mail-add
 (defun git-rev-parse (rev)
   "Parse a revision name and return its SHA1."
   (git-get-string-sha1
-   (with-output-to-string
-     (with-current-buffer standard-output
-       (git-call-process-env t nil "rev-parse" rev)))))
+   (git-call-process-env-string nil "rev-parse" rev)))
+
+(defun git-repo-config (key)
+  "Retrieve the value associated to KEY in the git repository config file."
+  (let ((str (git-call-process-env-string nil "repo-config" key)))
+    (and str (car (split-string str "\n")))))
 
 (defun git-symbolic-ref (ref)
   "Wrapper for the git-symbolic-ref command."
-  (car
-   (split-string
-    (with-output-to-string
-      (with-current-buffer standard-output
-        (git-call-process-env t nil "symbolic-ref" ref)))
-    "\n")))
+  (let ((str (git-call-process-env-string nil "symbolic-ref" ref)))
+    (and str (car (split-string str "\n")))))
 
 (defun git-update-ref (ref val &optional oldval)
   "Update a reference by calling git-update-ref."
@@ -285,11 +293,7 @@ The default is to fall back to `add-log-mailing-address' and then `user-mail-add
 (defun git-write-tree (&optional index-file)
   "Call git-write-tree and return the resulting tree SHA1 as a string."
   (git-get-string-sha1
-   (with-output-to-string
-     (with-current-buffer standard-output
-       (git-call-process-env t
-        (if index-file `(("GIT_INDEX_FILE" . ,index-file)) nil)
-        "write-tree")))))
+   (git-call-process-env-string (and index-file `(("GIT_INDEX_FILE" . ,index-file))) "write-tree")))
 
 (defun git-commit-tree (buffer tree head)
   "Call git-commit-tree with buffer as input and return the resulting commit SHA1."
@@ -763,6 +767,16 @@ The default is to fall back to `add-log-mailing-address' and then `user-mail-add
     (git-setup-diff-buffer
      (apply #'git-run-command-buffer "*git-diff*" "diff-index" "-p" "-M" "HEAD" "--" (git-get-filenames files)))))
 
+(defun git-diff-file-merge-head (arg)
+  "Diff the marked file(s) against the first merge head (or the nth one with a numeric prefix)."
+  (interactive "p")
+  (let ((files (git-marked-files))
+        (merge-heads (git-get-merge-heads)))
+    (unless merge-heads (error "No merge in progress"))
+    (git-setup-diff-buffer
+     (apply #'git-run-command-buffer "*git-diff*" "diff-index" "-p" "-M"
+            (or (nth (1- arg) merge-heads) "HEAD") "--" (git-get-filenames files)))))
+
 (defun git-diff-unmerged-file (stage)
   "Diff the marked unmerged file(s) against the specified stage."
   (let ((files (git-marked-files)))
@@ -955,6 +969,7 @@ The default is to fall back to `add-log-mailing-address' and then `user-mail-add
     (define-key diff-map "=" 'git-diff-file)
     (define-key diff-map "e" 'git-diff-file-idiff)
     (define-key diff-map "E" 'git-find-file-imerge)
+    (define-key diff-map "h" 'git-diff-file-merge-head)
     (define-key diff-map "m" 'git-diff-file-mine)
     (define-key diff-map "o" 'git-diff-file-other)
     (setq git-status-mode-map map)))
diff --git a/generate-cmdlist.sh b/generate-cmdlist.sh
index 6ee85d5a53..6c59dbd68f 100755
--- a/generate-cmdlist.sh
+++ b/generate-cmdlist.sh
@@ -41,8 +41,12 @@ whatchanged
 EOF
 while read cmd
 do
-    sed -n "/NAME/,/git-$cmd/H;
-	    \$ {x; s/.*git-$cmd - \\(.*\\)/  {\"$cmd\", \"\1\"},/; p}" \
-	"Documentation/git-$cmd.txt"
+     sed -n '
+     /NAME/,/git-'"$cmd"'/H
+     ${
+            x
+            s/.*git-'"$cmd"' - \(.*\)/  {"'"$cmd"'", "\1"},/
+	    p
+     }' "Documentation/git-$cmd.txt"
 done
 echo "};"
diff --git a/git-merge.sh b/git-merge.sh
index cc0952a97d..78ab422e4e 100755
--- a/git-merge.sh
+++ b/git-merge.sh
@@ -11,11 +11,15 @@ LF='
 '
 
 all_strategies='recursive octopus resolve stupid ours'
-default_strategies='recursive'
+default_twohead_strategies='recursive'
+default_octopus_strategies='octopus'
+no_trivial_merge_strategies='ours'
 use_strategies=
+
+index_merge=t
 if test "@@NO_PYTHON@@"; then
 	all_strategies='resolve octopus stupid ours'
-	default_strategies='resolve'
+	default_twohead_strategies='resolve'
 fi
 
 dropsave() {
@@ -90,8 +94,6 @@ do
 	shift
 done
 
-test "$#" -le 2 && usage ;# we need at least two heads.
-
 merge_msg="$1"
 shift
 head_arg="$1"
@@ -99,6 +101,8 @@ head=$(git-rev-parse --verify "$1"^0) || usage
 shift
 
 # All the rest are remote heads
+test "$#" = 0 && usage ;# we need at least one remote head.
+
 remoteheads=
 for remote
 do
@@ -108,6 +112,27 @@ do
 done
 set x $remoteheads ; shift
 
+case "$use_strategies" in
+'')
+	case "$#" in
+	1)
+		use_strategies="$default_twohead_strategies" ;;
+	*)
+		use_strategies="$default_octopus_strategies" ;;
+	esac
+	;;
+esac
+
+for s in $use_strategies
+do
+	case " $s " in
+	*" $no_trivial_merge_strategies "*)
+		index_merge=f
+		break
+		;;
+	esac
+done
+
 case "$#" in
 1)
 	common=$(git-merge-base --all $head "$@")
@@ -118,18 +143,21 @@ case "$#" in
 esac
 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 
-case "$#,$common,$no_commit" in
-*,'',*)
+case "$index_merge,$#,$common,$no_commit" in
+f,*)
+	# We've been told not to try anything clever.  Skip to real merge.
+	;;
+?,*,'',*)
 	# No common ancestors found. We need a real merge.
 	;;
-1,"$1",*)
+?,1,"$1",*)
 	# If head can reach all the merge then we are up to date.
-	# but first the most common case of merging one remote
+	# but first the most common case of merging one remote.
 	echo "Already up-to-date."
 	dropsave
 	exit 0
 	;;
-1,"$head",*)
+?,1,"$head",*)
 	# Again the most common case of merging one remote.
 	echo "Updating from $head to $1"
 	git-update-index --refresh 2>/dev/null
@@ -139,11 +167,11 @@ case "$#,$common,$no_commit" in
 	dropsave
 	exit 0
 	;;
-1,?*"$LF"?*,*)
+?,1,?*"$LF"?*,*)
 	# We are not doing octopus and not fast forward.  Need a
 	# real merge.
 	;;
-1,*,)
+?,1,*,)
 	# We are not doing octopus, not fast forward, and have only
 	# one common.  See if it is really trivial.
 	git var GIT_COMMITTER_IDENT >/dev/null || exit
@@ -188,17 +216,6 @@ esac
 # We are going to make a new commit.
 git var GIT_COMMITTER_IDENT >/dev/null || exit
 
-case "$use_strategies" in
-'')
-	case "$#" in
-	1)
-		use_strategies="$default_strategies" ;;
-	*)
-		use_strategies=octopus ;;
-	esac		
-	;;
-esac
-
 # At this point, we need a real merge.  No matter what strategy
 # we use, it would operate on the index, possibly affecting the
 # working tree, and when resolved cleanly, have the desired tree
@@ -270,11 +287,7 @@ done
 # auto resolved the merge cleanly.
 if test '' != "$result_tree"
 then
-    parents="-p $head"
-    for remote
-    do
-        parents="$parents -p $remote"
-    done
+    parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
     result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
     finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
     dropsave
diff --git a/sha1_file.c b/sha1_file.c
index a80d849f15..58edec0bb6 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -973,6 +973,16 @@ static void *unpack_delta_entry(unsigned char *base_sha1,
 
 	if (left < 20)
 		die("truncated pack file");
+
+	/* The base entry _must_ be in the same pack */
+	if (!find_pack_entry_one(base_sha1, &base_ent, p))
+		die("failed to find delta-pack base object %s",
+		    sha1_to_hex(base_sha1));
+	base = unpack_entry_gently(&base_ent, type, &base_size);
+	if (!base)
+		die("failed to read delta-pack base object %s",
+		    sha1_to_hex(base_sha1));
+
 	data = base_sha1 + 20;
 	data_size = left - 20;
 	delta_data = xmalloc(delta_size);
@@ -990,14 +1000,6 @@ static void *unpack_delta_entry(unsigned char *base_sha1,
 	if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 		die("delta data unpack failed");
 
-	/* The base entry _must_ be in the same pack */
-	if (!find_pack_entry_one(base_sha1, &base_ent, p))
-		die("failed to find delta-pack base object %s",
-		    sha1_to_hex(base_sha1));
-	base = unpack_entry_gently(&base_ent, type, &base_size);
-	if (!base)
-		die("failed to read delta-pack base object %s",
-		    sha1_to_hex(base_sha1));
 	result = patch_delta(base, base_size,
 			     delta_data, delta_size,
 			     &result_size);