This subcommand should be used when you have a branch or a part of a
branch that isn't easily bisectable because of a bug that has been
fixed latter.
We suppose that a bug as been introduced at some point, say A, and
that it has been fixed latter at another point, say B, but that
between these points the code is not easily testable because of the
bug, so it's not easy to bisect between these points.
In this case you can create a branch starting at the parent of A, say
O, that has a fixed history. In this fixed history for example, there
could be first a commit C that is the result of squashing A and B
together and then all the commits between A and B that have been
cherry picked.
For example, let's say the commits between A and B are X1, X2, ... Xn
and they have been cherry picked after C as Y1, Y2, ... Yn:
C--Y1--Y2--...--Yn
/
...--O--A--X1--X2--...--Xn--B--...
By design, the last cherry picked commit (Yn) should point to the same
tree as commit B.
So in this case you can say:
$ git bisect replace B Yn
and a branch will be created that points to commit Yn and that has a
special name like: "bisect-replace-B"
When bisecting, the branch names will be scanned and each branch named
"bisect-replace-X" and pointing to commit Y will be grafted so that
X will only have Y as parent.
In the example above, that means that instead of the above graph, the
following graph will be bisected:
C--Y1--Y2--...--Yn
/ \
...--O B--...
This means that the bisections on this branch will be much easier
because the bug introduced by commit A and fixed by commit B will not
annoy you anymore.
As the branches created by "git bisect replace" can be shared between
developers, this feature might be especially usefull on big projects
where many people often bisect the same code base.
Signed-off-by: Christian Couder <chriscool@xxxxxxxxxxxxx>
---
builtin-rev-list.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++-
git-bisect.sh | 37 +++++++++++++++++++++++++-
2 files changed, 105 insertions(+), 3 deletions(-)
Changes since the previous series (v3) are the following:
- move 2 lines of code in patch 1,
- added tests in patch 7,
- added --no-replace option (patches 8 and 9)
I still wonder about the following:
- perhaps "git bisect replace" should have a "NAME" argument
so that the branch names could be like "bisect-replace-X-NAME"
which could be more descriptive,
- maybe a way to check that the replace branches all point to
existing commits would be useful,
- perhaps bisect log/replay could be improved to handle
replace branches
But I think it's already possible to do many things in the
current state, especially by using "git branch -m" (to rename
branches). For example to give a more explicit name:
$ git branch -m bisect-replace-X bisect-replace-X-explicit-name
and to not replace a branch any more (but keep it in case you may
use it again latter):
$ git branch -m bisect-replace-Y bisect-do-not-replace-Y
...
So as I don't want to over-engineer this and I am a bit lazy too,
I will wait for some comments. Thanks in advance for them!
diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index 06cdeb7..c0717f6 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -574,6 +574,72 @@ static struct commit_list *find_bisection(struct commit_list *list,
return best;
}
+static void replace_parents(struct commit *commit,
+ const char *refname,
+ const unsigned char *sha1)
+{
+ struct commit *new_parent = lookup_commit(sha1);
+ if (!new_parent) {
+ warning("branch '%s' points to unknown commit '%s'",
+ refname, sha1_to_hex(sha1));
+ return;
+ }
+
+ free_commit_list(commit->parents);
+ commit->parents = NULL;
+ commit_list_insert(new_parent, &commit->parents);
+}
+
+static int bisect_replace(const char *refname, const unsigned char *sha1,
+ int flag, void *cb_data)
+{
+ unsigned char child[20];
+ struct object *obj;
+ struct commit_graft *graft;
+
+ if (prefixcmp(refname, "bisect-replace-"))
+ return 0;
+
+ if (get_sha1_hex(refname + 15, child)) {
+ warning("bad sha1 in branch name '%s'", refname);
+ return 0;
+ }
+
+ /* Check if child commit exist and is already parsed */
+
+ obj = lookup_object(child);
+ if (obj) {
+ struct commit *commit;
+ if (obj->type != OBJ_COMMIT) {
+ warning("branch name '%s' refers to non commit '%s'",
+ refname, refname + 15);
+ return 0;
+ }
+ commit = (struct commit *) obj;
+ if (commit->object.parsed) {
+ replace_parents(commit, refname, sha1);
+ return 0;
+ }
+ }
+
+ /* Create a graft to replace child commit parents */
+
+ graft = xmalloc(sizeof(*graft) + 20);
+
+ hashcpy(graft->sha1, child);
+ graft->nr_parent = 1;
+ hashcpy(graft->parent[0], sha1);
+
+ register_commit_graft(graft, 1);
+
+ return 0;
+}
+
+static void bisect_replace_all(void)
+{
+ for_each_branch_ref(bisect_replace, NULL);
+}
+
int cmd_rev_list(int argc, const char **argv, const char *prefix)
{
struct commit_list *list;
@@ -646,8 +712,11 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
save_commit_buffer = revs.verbose_header ||
revs.grep_filter.pattern_list;
- if (bisect_list)
+
+ if (bisect_list) {
+ bisect_replace_all();
revs.limited = 1;
+ }
if (prepare_revision_walk(&revs))
die("revision walk setup failed");
diff --git a/git-bisect.sh b/git-bisect.sh
index 0d0e278..b0139d5 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -1,6 +1,6 @@
#!/bin/sh
-USAGE='[help|start|bad|good|skip|next|reset|visualize|replay|log|run]'
+USAGE='[help|start|bad|good|skip|next|reset|visualize|replay|log|replace|run]'
LONG_USAGE='git bisect help
print this long help message.
git bisect start [<bad> [<good>...]] [--] [<pathspec>...]
@@ -21,6 +21,8 @@ git bisect replay <logfile>
replay bisection log.
git bisect log
show bisect log.
+git bisect replace <rev> [<rev>]
+ use another branch for bisection.
git bisect run <cmd>...
use <cmd>... to automatically bisect.
@@ -566,6 +568,36 @@ bisect_replay () {
bisect_auto_next
}
+bisect_replace() {
+ test "$#" -ge 1 -a "$#" -le 2 ||
+ die "'git bisect replace' accept one or two arguments"
+
+ source="$1"
+ target="${2:-HEAD}"
+
+ # Check arguments
+ src_commit=$(git rev-parse --verify "$source^{commit}") ||
+ die "Bad rev input: $source"
+ tgt_commit=$(git rev-parse --verify "$target^{commit}") ||
+ die "Bad rev input: $target"
+
+ test "$src_commit" != "tgt_commit" ||
+ die "source and target should be different commits"
+
+ # Check that trees from source and target are identical
+ src_tree=$(git rev-parse --verify "$src_commit^{tree}") ||
+ die "Could not get tree for source: $source"
+ tgt_tree=$(git rev-parse --verify "$tgt_commit^{tree}") ||
+ die "Could not get tree for target: $target"
+
+ test "$src_tree" = "$tgt_tree" ||
+ die "source and target should point to the same tree"
+
+ # Create branch for the target commit
+ tgt_branch="bisect-replace-$src_commit"
+ git branch "$tgt_branch" "$tgt_commit"
+}
+
bisect_run () {
bisect_next_check fail
@@ -618,7 +650,6 @@ bisect_run () {
done
}
-
case "$#" in
0)
usage ;;
@@ -643,6 +674,8 @@ case "$#" in
bisect_replay "$@" ;;
log)
cat "$GIT_DIR/BISECT_LOG" ;;
+ replace)
+ bisect_replace "$@" ;;
run)
bisect_run "$@" ;;
*)
--
1.6.0.3.614.g0f3b9
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