Upon seeing a merge commit when bisecting, this option may be used to
follow only the first parent.
In detecting regressions introduced through the merging of a branch, the
merge commit will be identified as introduction of the bug and its
ancestors will be ignored.
This option is particularly useful in avoiding false positives when a
merged branch contained broken or non-buildable commits, but the merge
itself was OK.
Signed-off-by: Aaron Lipman <alipman88@xxxxxxxxx>
---
Documentation/git-bisect.txt | 13 ++++++++++++-
bisect.c | 10 +++++++++-
builtin/bisect--helper.c | 14 ++++++++++----
t/t6030-bisect-porcelain.sh | 18 ++++++++++++++++++
4 files changed, 49 insertions(+), 6 deletions(-)
diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt
index 7586c5a843..0e993e4587 100644
--- a/Documentation/git-bisect.txt
+++ b/Documentation/git-bisect.txt
@@ -17,7 +17,7 @@ The command takes various subcommands, and different options depending
on the subcommand:
git bisect start [--term-{old,good}=<term> --term-{new,bad}=<term>]
- [--no-checkout] [<bad> [<good>...]] [--] [<paths>...]
+ [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]
git bisect (bad|new|<term-new>) [<rev>]
git bisect (good|old|<term-old>) [<rev>...]
git bisect terms [--term-good | --term-bad]
@@ -365,6 +365,17 @@ does not require a checked out tree.
+
If the repository is bare, `--no-checkout` is assumed.
+--first-parent::
++
+Follow only the first parent commit upon seeing a merge commit.
++
+In detecting regressions introduced through the merging of a branch, the merge
+commit will be identified as introduction of the bug and its ancestors will be
+ignored.
++
+This option is particularly useful in avoiding false positives when a merged
+branch contained broken or non-buildable commits, but the merge itself was OK.
+
EXAMPLES
--------
diff --git a/bisect.c b/bisect.c
index a11fdb1473..afbb5aea32 100644
--- a/bisect.c
+++ b/bisect.c
@@ -460,6 +460,7 @@ static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
+static GIT_PATH_FUNC(git_path_bisect_first_parent, "BISECT_FIRST_PARENT")
static GIT_PATH_FUNC(git_path_head_name, "head-name")
static void read_bisect_paths(struct argv_array *array)
@@ -981,6 +982,12 @@ void read_bisect_terms(const char **read_bad, const char **read_good)
fclose(fp);
}
+static int read_first_parent_option(void)
+{
+ const char *filename = git_path_bisect_first_parent();
+ return !access(filename, F_OK);
+}
+
/*
* We use the convention that return BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND (-10) means
* the bisection process finished successfully.
@@ -997,7 +1004,7 @@ enum bisect_error bisect_next_all(struct repository *r, const char *prefix, int
enum bisect_error res = BISECT_OK;
struct object_id *bisect_rev;
char *steps_msg;
- int first_parent_only = 0; /* TODO: pass --first-parent flag from git bisect start */
+ int first_parent_only = read_first_parent_option();
read_bisect_terms(&term_bad, &term_good);
if (read_bisect_refs())
@@ -1141,6 +1148,7 @@ int bisect_clean_state(void)
unlink_or_warn(git_path_bisect_names());
unlink_or_warn(git_path_bisect_run());
unlink_or_warn(git_path_bisect_terms());
+ unlink_or_warn(git_path_bisect_first_parent());
/* Cleanup head-name if it got left by an old version of git-bisect */
unlink_or_warn(git_path_head_name());
/*
diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index ec4996282e..9273140f0b 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -17,6 +17,7 @@ static GIT_PATH_FUNC(git_path_bisect_head, "BISECT_HEAD")
static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
static GIT_PATH_FUNC(git_path_head_name, "head-name")
static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
+static GIT_PATH_FUNC(git_path_bisect_first_parent, "BISECT_FIRST_PARENT")
static const char * const git_bisect_helper_usage[] = {
N_("git bisect--helper --next-all [--no-checkout]"),
@@ -28,7 +29,7 @@ static const char * const git_bisect_helper_usage[] = {
N_("git bisect--helper --bisect-next-check <good_term> <bad_term> [<term>]"),
N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
N_("git bisect--helper --bisect-start [--term-{old,good}=<term> --term-{new,bad}=<term>]"
- "[--no-checkout] [<bad> [<good>...]] [--] [<paths>...]"),
+ " [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]"),
NULL
};
@@ -422,7 +423,7 @@ static int bisect_append_log_quoted(const char **argv)
}
static int bisect_start(struct bisect_terms *terms, int no_checkout,
- const char **argv, int argc)
+ int first_parent_only, const char **argv, int argc)
{
int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
int flags, pathspec_pos, res = 0;
@@ -577,6 +578,9 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
*/
write_file(git_path_bisect_start(), "%s\n", start_head.buf);
+ if (first_parent_only)
+ write_file(git_path_bisect_first_parent(), "\n");
+
if (no_checkout) {
if (get_oid(start_head.buf, &oid) < 0) {
res = error(_("invalid ref: '%s'"), start_head.buf);
@@ -632,7 +636,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
BISECT_TERMS,
BISECT_START
} cmdmode = 0;
- int no_checkout = 0, res = 0, nolog = 0;
+ int no_checkout = 0, first_parent_only = 0, res = 0, nolog = 0;
struct option options[] = {
OPT_CMDMODE(0, "next-all", &cmdmode,
N_("perform 'git bisect next'"), NEXT_ALL),
@@ -656,6 +660,8 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
N_("start the bisect session"), BISECT_START),
OPT_BOOL(0, "no-checkout", &no_checkout,
N_("update BISECT_HEAD instead of checking out the current commit")),
+ OPT_BOOL(0, "first-parent", &first_parent_only,
+ N_("only trace the first parent of merge commits")),
OPT_BOOL(0, "no-log", &nolog,
N_("no log for BISECT_WRITE")),
OPT_END()
@@ -713,7 +719,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
break;
case BISECT_START:
set_terms(&terms, "bad", "good");
- res = bisect_start(&terms, no_checkout, argv, argc);
+ res = bisect_start(&terms, no_checkout, first_parent_only, argv, argc);
break;
default:
return error("BUG: unknown subcommand '%d'", cmdmode);
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 36d9b2b2e4..51f5eb6ea3 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -458,6 +458,24 @@ test_expect_success 'many merge bases creation' '
grep "$SIDE_HASH5" merge_bases.txt
'
+# We want to automatically find the merge that
+# added "line" into hello.
+test_expect_success '"git bisect run --first-parent" simple case' '
+ git rev-list --first-parent $B_HASH ^$HASH4 >first_parent_chain.txt &&
+ write_script test_script.sh <<-\EOF &&
+ grep $(git rev-parse HEAD) first_parent_chain.txt || exit -1
+ ! grep line hello >/dev/null
+ EOF
+ git bisect start --first-parent &&
+ test_path_is_file ".git/BISECT_FIRST_PARENT" &&
+ git bisect good $HASH4 &&
+ git bisect bad $B_HASH &&
+ git bisect run ./test_script.sh >my_bisect_log.txt &&
+ grep "$B_HASH is the first bad commit" my_bisect_log.txt &&
+ git bisect reset &&
+ test_path_is_missing .git/BISECT_FIRST_PARENT
+'
+
test_expect_success 'good merge bases when good and bad are siblings' '
git bisect start "$B_HASH" "$A_HASH" > my_bisect_log.txt &&
test_i18ngrep "merge base must be tested" my_bisect_log.txt &&
--
2.24.3 (Apple Git-128)
