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 | 5 ++++-
builtin/bisect--helper.c | 9 ++++++++-
t/t6030-bisect-porcelain.sh | 18 ++++++++++++++++++
4 files changed, 42 insertions(+), 3 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 950ff6f533..bc4241b51f 100644
--- a/bisect.c
+++ b/bisect.c
@@ -15,6 +15,7 @@
#include "commit-slab.h"
#include "commit-reach.h"
#include "object-store.h"
+#include "dir.h"
static struct oid_array good_revs;
static struct oid_array skipped_revs;
@@ -460,6 +461,7 @@ 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)
@@ -998,7 +1000,7 @@ enum bisect_error bisect_next_all(struct repository *r, const char *prefix)
struct object_id *bisect_rev;
char *steps_msg;
int no_checkout = ref_exists("BISECT_HEAD");
- int first_parent_only = 0; /* TODO: pass --first-parent flag from git bisect start */
+ int first_parent_only = file_exists(git_path_bisect_first_parent());
read_bisect_terms(&term_bad, &term_good);
if (read_bisect_refs())
@@ -1142,6 +1144,7 @@ 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 95a15b918f..a055147f19 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -16,6 +16,7 @@ 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_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"),
@@ -27,7 +28,7 @@ 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
};
@@ -423,6 +424,7 @@ static int bisect_append_log_quoted(const char **argv)
static int bisect_start(struct bisect_terms *terms, const char **argv, int argc)
{
int no_checkout = 0;
+ int first_parent_only = 0;
int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
int flags, pathspec_pos, res = 0;
struct string_list revs = STRING_LIST_INIT_DUP;
@@ -452,6 +454,8 @@ static int bisect_start(struct bisect_terms *terms, const char **argv, int argc)
break;
} else if (!strcmp(arg, "--no-checkout")) {
no_checkout = 1;
+ } else if (!strcmp(arg, "--first-parent")) {
+ first_parent_only = 1;
} else if (!strcmp(arg, "--term-good") ||
!strcmp(arg, "--term-old")) {
i++;
@@ -576,6 +580,9 @@ static int bisect_start(struct bisect_terms *terms, const char **argv, int argc)
*/
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);
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index a66c4b89bc..b886529e59 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -448,6 +448,24 @@ 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)
