One of the first things done by the interactive rebase is to make a todo
list. This requires knowledge of the commit range to rebase. To get
the oid of the last commit of the range, the tip of the branch to rebase
is checked out with prepare_branch_to_be_rebased(), then the oid of the
HEAD is read. On big repositories, it's a performance penalty: the user
may have to wait before editing the todo list while git is extracting the
branch silently (because git-checkout is silenced here). After this,
the head of the branch is not even modified.
Since we already have the oid of the tip of the branch in
`opts->orig_head', it's useless to switch to this commit.
This removes the call to prepare_branch_to_be_rebased() in
do_interactive_rebase(), and adds a `orig_head' parameter to
get_revision_ranges(). prepare_branch_to_be_rebased() is removed as it
is no longer used.
This introduces a visible change: as we do not switch on the tip of the
branch to rebase, no reflog entry is created at the beginning of the
rebase for it.
Reported-by: SZEDER Gábor <szeder.dev@xxxxxxxxx>
Signed-off-by: Alban Gruin <alban.gruin@xxxxxxxxx>
---
Notes:
Improvements brought by this patch:
Before:
$ time git rebase -m --onto v4.18 463fa44eec2fef50~ 463fa44eec2fef50
real 0m8,940s
user 0m6,830s
sys 0m2,121s
After:
$ time git rebase -m --onto v4.18 463fa44eec2fef50~ 463fa44eec2fef50
real 0m1,834s
user 0m0,916s
sys 0m0,206s
Both tests have been performed on a 5400 RPM SATA III hard drive.
builtin/rebase.c | 18 +++++-------------
sequencer.c | 14 --------------
sequencer.h | 3 ---
3 files changed, 5 insertions(+), 30 deletions(-)
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 8081741f8a..6154ad8fa5 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -246,21 +246,17 @@ static int edit_todo_file(unsigned flags)
}
static int get_revision_ranges(struct commit *upstream, struct commit *onto,
- const char **head_hash,
+ struct object_id *orig_head, const char **head_hash,
char **revisions, char **shortrevisions)
{
struct commit *base_rev = upstream ? upstream : onto;
const char *shorthead;
- struct object_id orig_head;
-
- if (get_oid("HEAD", &orig_head))
- return error(_("no HEAD?"));
- *head_hash = find_unique_abbrev(&orig_head, GIT_MAX_HEXSZ);
+ *head_hash = find_unique_abbrev(orig_head, GIT_MAX_HEXSZ);
*revisions = xstrfmt("%s...%s", oid_to_hex(&base_rev->object.oid),
*head_hash);
- shorthead = find_unique_abbrev(&orig_head, DEFAULT_ABBREV);
+ shorthead = find_unique_abbrev(orig_head, DEFAULT_ABBREV);
if (upstream) {
const char *shortrev;
@@ -314,12 +310,8 @@ static int do_interactive_rebase(struct rebase_options *opts, unsigned flags)
struct replay_opts replay = get_replay_opts(opts);
struct string_list commands = STRING_LIST_INIT_DUP;
- if (prepare_branch_to_be_rebased(the_repository, &replay,
- opts->switch_to))
- return -1;
-
- if (get_revision_ranges(opts->upstream, opts->onto, &head_hash,
- &revisions, &shortrevisions))
+ if (get_revision_ranges(opts->upstream, opts->onto, &opts->orig_head,
+ &head_hash, &revisions, &shortrevisions))
return -1;
if (init_basic_state(&replay,
diff --git a/sequencer.c b/sequencer.c
index b9dbf1adb0..4dc245d7ec 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -3715,20 +3715,6 @@ static int run_git_checkout(struct repository *r, struct replay_opts *opts,
return ret;
}
-int prepare_branch_to_be_rebased(struct repository *r, struct replay_opts *opts,
- const char *commit)
-{
- const char *action;
-
- if (commit && *commit) {
- action = reflog_message(opts, "start", "checkout %s", commit);
- if (run_git_checkout(r, opts, commit, action))
- return error(_("could not checkout %s"), commit);
- }
-
- return 0;
-}
-
static int checkout_onto(struct repository *r, struct replay_opts *opts,
const char *onto_name, const struct object_id *onto,
const char *orig_head)
diff --git a/sequencer.h b/sequencer.h
index 9f9ae291e3..74f1e2673e 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -190,9 +190,6 @@ void commit_post_rewrite(struct repository *r,
const struct commit *current_head,
const struct object_id *new_head);
-int prepare_branch_to_be_rebased(struct repository *r, struct replay_opts *opts,
- const char *commit);
-
#define SUMMARY_INITIAL_COMMIT (1 << 0)
#define SUMMARY_SHOW_AUTHOR_DATE (1 << 1)
void print_commit_summary(struct repository *repo,
--
2.24.1
