[PATCH] cherry-pick: add --keep-existing-origin option

[Anthony Wong <anthony.wong@canonical.com>]

When cherry-picking from a commit whose commit message already
contains the "(cherry picked from commit ...)" line, this option will
not add another one. This is useful when you are cherry-picking from a
bunch of commits, some are cherry-picks and already contains the
upstream hash but some do not. Use with -x.

Signed-off-by: Anthony Wong <yp@anthonywong.net>
---
 Documentation/git-cherry-pick.txt |  8 ++++++++
 builtin/revert.c                  |  2 ++
 sequencer.c                       | 14 ++++++++------
 sequencer.h                       |  1 +
 4 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/Documentation/git-cherry-pick.txt b/Documentation/git-cherry-pick.txt
index d35d771fc..7a074511f 100644
--- a/Documentation/git-cherry-pick.txt
+++ b/Documentation/git-cherry-pick.txt
@@ -71,6 +71,14 @@ OPTIONS
 	development branch), adding this information can be
 	useful.
 
+--keep-existing-origin::
+	This option has to be used with -x to take effect. When
+	cherry-picking from a commit whose commit message already
+	contains the "(cherry picked from commit ...)" line, this
+	option will not add another one. This is useful when you are
+	cherry-picking from a bunch of commits, some are cherry-picks
+	and already contains the upstream hash but some do not.
+
 -r::
 	It used to be that the command defaulted to do `-x`
 	described above, and `-r` was to disable it.  Now the
diff --git a/builtin/revert.c b/builtin/revert.c
index b9d927eb0..a1900cc1d 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -122,6 +122,7 @@ static int run_sequencer(int argc, const char **argv, struct replay_opts *opts)
 			OPT_BOOL(0, "allow-empty", &opts->allow_empty, N_("preserve initially empty commits")),
 			OPT_BOOL(0, "allow-empty-message", &opts->allow_empty_message, N_("allow commits with empty messages")),
 			OPT_BOOL(0, "keep-redundant-commits", &opts->keep_redundant_commits, N_("keep redundant, empty commits")),
+			OPT_BOOL(0, "keep-existing-origin", &opts->keep_existing_origin, N_("do not add another hash if one already exists, use with -x")),
 			OPT_END(),
 		};
 		options = parse_options_concat(options, cp_extra);
@@ -157,6 +158,7 @@ static int run_sequencer(int argc, const char **argv, struct replay_opts *opts)
 				"--ff", opts->allow_ff,
 				"--rerere-autoupdate", opts->allow_rerere_auto == RERERE_AUTOUPDATE,
 				"--no-rerere-autoupdate", opts->allow_rerere_auto == RERERE_NOAUTOUPDATE,
+				"--keep-existing-origin", opts->keep_existing_origin,
 				NULL);
 	}
 
diff --git a/sequencer.c b/sequencer.c
index f2a10cc4f..c96add16e 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1050,12 +1050,14 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 			strbuf_addstr(&msgbuf, p);
 
 		if (opts->record_origin) {
-			strbuf_complete_line(&msgbuf);
-			if (!has_conforming_footer(&msgbuf, NULL, 0))
-				strbuf_addch(&msgbuf, '\n');
-			strbuf_addstr(&msgbuf, cherry_picked_prefix);
-			strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
-			strbuf_addstr(&msgbuf, ")\n");
+			if (!opts->keep_existing_origin || strstr(msgbuf.buf, cherry_picked_prefix) == NULL) {
+				strbuf_complete_line(&msgbuf);
+				if (!has_conforming_footer(&msgbuf, NULL, 0))
+					strbuf_addch(&msgbuf, '\n');
+				strbuf_addstr(&msgbuf, cherry_picked_prefix);
+				strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
+				strbuf_addstr(&msgbuf, ")\n");
+			}
 		}
 	}
 
diff --git a/sequencer.h b/sequencer.h
index 6f3d3df82..a907c0947 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -24,6 +24,7 @@ struct replay_opts {
 	int allow_empty;
 	int allow_empty_message;
 	int keep_redundant_commits;
+	int keep_existing_origin;
 	int verbose;
 
 	int mainline;
-- 
2.14.1