[PATCH v2 13/13] Add option --preserve-tags

["Jörg Sommer" <joerg@alea.gnuu.de>]

With this new option tags set on commits, they are part of a rebase, are
reset to the rebased commits. This way the tags on a branch are kept
across rebases.

Signed-off-by: Jörg Sommer <joerg@alea.gnuu.de>
---
 Documentation/git-rebase.txt  |    6 ++++-
 git-rebase--interactive.sh    |   42 ++++++++++++++++++++++++++++++++++++++--
 t/t3404-rebase-interactive.sh |   10 +++++++++
 3 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 9ebbb90..cc4e94f 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -11,7 +11,8 @@ SYNOPSIS
 'git-rebase' [-i | --interactive] [-v | --verbose] [-m | --merge]
 	[-s <strategy> | --strategy=<strategy>]
 	[-C<n>] [ --whitespace=<option>] [-p | --preserve-merges]
-	[-f | --first-parent] [--onto <newbase>] <upstream> [<branch>]
+	[-f | --first-parent] [-t | --preserve-tags]
+	[--onto <newbase>] <upstream> [<branch>]
 'git-rebase' --continue | --skip | --abort
 
 DESCRIPTION
@@ -252,6 +253,9 @@ OPTIONS
 	showing all commits from the merged branches show only the
 	commits and merges following the first parent of each commit.
 
+-t, \--preserve-tags::
+	If one of the commits has a tag, reset it to the new commit object.
+
 include::merge-strategies.txt[]
 
 NOTES
diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index c601655..e874c31 100755
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -11,7 +11,7 @@
 # http://article.gmane.org/gmane.comp.version-control.git/22407
 
 USAGE='(--continue | --abort | --skip | [--preserve-merges] [--first-parent]
-	[--verbose] [--onto <branch>] <upstream> [<branch>])'
+	[--preserve-tags] [--verbose] [--onto <branch>] <upstream> [<branch>])'
 
 OPTIONS_SPEC=
 . git-sh-setup
@@ -397,9 +397,31 @@ insert_value_at_key_into_list () {
 
 create_extended_todo_list () {
 	(
+	if test t = "${PRESERVE_TAGS:-}"
+	then
+		tag_list=$(git show-ref --abbrev=7 --tags | \
+			(
+			while read sha1 tag
+			do
+				tag=${tag#refs/tags/}
+				if test ${last_sha1:-0000} = $sha1
+				then
+					saved_tags="$saved_tags:$tag"
+				else
+					printf "%s" "${last_sha1:+ $last_sha1#$saved_tags}"
+					last_sha1=$sha1
+					saved_tags=$tag
+				fi
+			done
+			echo "${last_sha1:+ $last_sha1:$saved_tags}"
+			) )
+	else
+		tag_list=
+	fi
 	while IFS=_ read commit parents subject
 	do
-		if test "${last_parent:-$commit}" != "$commit"
+		if test t = "$PRESERVE_MERGES" -a \
+			"${last_parent:-$commit}" != "$commit"
 		then
 			if test t = "${delayed_mark:-f}"
 			then
@@ -416,6 +438,14 @@ create_extended_todo_list () {
 		get_value_from_list $commit "${marked_commits:-}" \
 			>/dev/null && echo mark
 
+		if tmp=$(get_value_from_list $commit "$tag_list")
+		then
+			for t in $(echo $tmp | tr : ' ')
+			do
+				echo tag $t
+			done
+		fi
+
 		case "$parents" in
 		*' '*)
 			delayed_mark=t
@@ -575,6 +605,9 @@ do
 		FIRST_PARENT=t
 		PRESERVE_MERGES=t
 		;;
+	-t|--preserve-tags)
+		PRESERVE_TAGS=t
+		;;
 	-i|--interactive)
 		# yeah, we know
 		;;
@@ -631,11 +664,14 @@ do
 		SHORTONTO=$(git rev-parse --short=7 $ONTO)
 		common_rev_list_opts="--abbrev-commit --abbrev=7
 			--left-right --cherry-pick $UPSTREAM...$HEAD"
-		if test t = "$PRESERVE_MERGES" -o t = "${FIRST_PARENT:-f}"
+		if test t = "$PRESERVE_MERGES" -o t = "${FIRST_PARENT:-f}" \
+			-o t = "${PRESERVE_TAGS:-}"
 		then
 			opts=
 			test t = "${FIRST_PARENT:-f}" && \
 				opts="$opts --first-parent"
+			test t != "$PRESERVE_MERGES" && \
+				opts="$opts --no-merges"
 			git rev-list --pretty='format:%h_%p_%s' --topo-order \
 				$opts $common_rev_list_opts | \
 				grep -v ^commit | \
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 9901555..d20ed4f 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -319,6 +319,16 @@ test_expect_success 'tag sets tags' '
 		"$(git rev-parse HEAD^2~2 HEAD~2 HEAD~1 HEAD~1)"
 '
 
+test_expect_success 'interactive -t preserves tags' '
+	git rebase -i -p -t --onto dead-end master &&
+	test "$(git rev-parse bb-tag1 bb-tag2 bb-tag3a bb-tag3b)" = \
+		"$(git rev-parse HEAD^2~2 HEAD~2 HEAD~1 HEAD~1)" &&
+	head=$(git rev-parse HEAD) &&
+	git rebase -i -t dead-end &&
+	test "$(git rev-parse bb-tag1 bb-tag2 bb-tag3a bb-tag3b)" = \
+		"$(git rev-parse HEAD~7 $head~2 HEAD~1 HEAD~1)"
+'
+
 test_expect_success '--continue tries to commit' '
 	git checkout to-be-rebased &&
 	test_tick &&
-- 
1.5.5