merge, pull: add '--(no-)log' command line option

These are the command line option equivalents of the 'merge.log' config
variable.

The patch also updates documentation and bash completion accordingly, and
adds a test.

Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/merge-options.txt

@@ -9,6 +9,15 @@
 	Synonyms to --stat and --no-stat; these are deprecated and will be
 	removed in the future.
 
+--log::
+	In addition to branch names, populate the log message with
+	one-line descriptions from the actual commits that are being
+	merged.
+
+--no-log::
+	Do not list one-line descriptions from the actual commits being
+	merged.
+
 --no-commit::
 	Perform the merge but pretend the merge failed and do
 	not autocommit, to give the user a chance to inspect and

contrib/completion/git-completion.bash

@@ -779,7 +779,7 @@ _git_merge ()
 		;;
 	--*)
 		__gitcomp "
-			--no-commit --no-stat --squash --strategy
+			--no-commit --no-stat --log --no-log --squash --strategy
 			"
 		return
 	esac

git-merge.sh

@@ -12,6 +12,8 @@ stat                 show a diffstat at the end of the merge
 n,no-stat            don't show a diffstat at the end of the merge
 summary              (synonym to --stat)
 no-summary           (synonym to --no-stat)
+log                  add list of one-line log to merge commit message
+no-log               don't add list of one-line log to merge commit message
 squash               create a single commit instead of doing a merge
 commit               perform a commit if the merge sucesses (default)
 ff                   allow fast forward (default)
@@ -39,7 +41,7 @@ use_strategies=
 
 allow_fast_forward=t
 allow_trivial_merge=t
-squash= no_commit=
+squash= no_commit= log_arg=
 
 dropsave() {
 	rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
@@ -154,6 +156,8 @@ parse_config () {
 			show_diffstat=false ;;
 		--stat|--summary)
 			show_diffstat=t ;;
+		--log|--no-log)
+			log_arg=$1 ;;
 		--squash)
 			test "$allow_fast_forward" = t ||
 				die "You cannot combine --squash with --no-ff."
@@ -261,7 +265,7 @@ else
 	merge_name=$(for remote
 		do
 			merge_name "$remote"
-		done | git fmt-merge-msg
+		done | git fmt-merge-msg $log_arg
 	)
 	merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
 fi

git-pull.sh

@@ -16,7 +16,7 @@ cd_to_toplevel
 test -z "$(git ls-files -u)" ||
 	die "You are in the middle of a conflicted merge."
 
-strategy_args= no_stat= no_commit= squash= no_ff=
+strategy_args= no_stat= no_commit= squash= no_ff= log_arg=
 curr_branch=$(git symbolic-ref -q HEAD)
 curr_branch_short=$(echo "$curr_branch" | sed "s|refs/heads/||")
 rebase=$(git config --bool branch.$curr_branch_short.rebase)
@@ -27,6 +27,8 @@ do
 		no_stat=-n ;;
 	--stat|--summary)
 		no_stat=$1 ;;
+	--log|--no-log)
+		log_arg=$1 ;;
 	--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
 		no_commit=--no-commit ;;
 	--c|--co|--com|--comm|--commi|--commit)
@@ -170,9 +172,9 @@ then
 	exit
 fi
 
-merge_name=$(git fmt-merge-msg <"$GIT_DIR/FETCH_HEAD") || exit
+merge_name=$(git fmt-merge-msg $log_arg <"$GIT_DIR/FETCH_HEAD") || exit
 test true = "$rebase" &&
 	exec git-rebase $strategy_args --onto $merge_head \
 	${oldremoteref:-$merge_head}
-exec git-merge $no_stat $no_commit $squash $no_ff $strategy_args \
+exec git-merge $no_stat $no_commit $squash $no_ff $log_arg $strategy_args \
 	"$merge_name" HEAD $merge_head

t/t7600-merge.sh

@@ -104,7 +104,11 @@ create_merge_msgs() {
 	git log --no-merges ^HEAD c2 >>squash.1-5 &&
 	echo "Squashed commit of the following:" >squash.1-5-9 &&
 	echo >>squash.1-5-9 &&
-	git log --no-merges ^HEAD c2 c3 >>squash.1-5-9
+	git log --no-merges ^HEAD c2 c3 >>squash.1-5-9 &&
+	echo > msg.nolog &&
+	echo "* commit 'c3':" >msg.log &&
+	echo "  commit 3" >>msg.log &&
+	echo >>msg.log
 }
 
 verify_diff() {
@@ -456,6 +460,16 @@ test_expect_success 'merge c0 with c1 (ff overrides no-ff)' '
 	verify_head $c1
 '
 
+test_expect_success 'merge log message' '
+	git reset --hard c0 &&
+	git merge --no-log c2 &&
+	git show -s --pretty=format:%b HEAD >msg.act &&
+	verify_diff msg.nolog msg.act "[OOPS] bad merge log message" &&
+	git merge --log c3 &&
+	git show -s --pretty=format:%b HEAD >msg.act &&
+	verify_diff msg.log msg.act "[OOPS] bad merge log message"
+'
+
 test_debug 'gitk --all'
 
 test_done