[PATCH v3] rev-list: skip --grep argument in early scan

[Azuama Odinaka Maximus <azuama69@gmail.com>]

The early option scan in rev-list does not account for options
that take a separate argument. As a result, a pattern passed to
--grep can be mistaken for another option.

Skip the argument to --grep so that it is not interpreted as an
option during the early scan.

The tests check that patterns beginning with "--" are actually
matched by --grep, including when the pattern resembles an option
that the early scan handles specially.

Signed-off-by: Azuama Odinaka Maximus <azuama69@gmail.com>
---
Changes in v3:
- Improve both regression tests to verify that --grep matches the
  expected commit when its pattern begins with "--".
- Add a blank line between the tests.

 builtin/rev-list.c          |  2 ++
 t/t6022-rev-list-missing.sh | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 0faa833fac..453d82d25c 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -771,6 +771,8 @@ int cmd_rev_list(int argc,
 			revs.exclude_promisor_objects = 1;
 		} else if (skip_prefix(arg, "--missing=", &arg)) {
 			parse_missing_action_value(repo, arg);
+		} else if (!strcmp(arg, "--grep")) {
+			i++;
 		} else if (!strcmp(arg, "--missing-only")) {
 			arg_missing_only = 1;
 		} else if (!strcmp(arg, "-z")) {
diff --git a/t/t6022-rev-list-missing.sh b/t/t6022-rev-list-missing.sh
index 1bd2c3bc4f..3757bde708 100755
--- a/t/t6022-rev-list-missing.sh
+++ b/t/t6022-rev-list-missing.sh
@@ -215,6 +215,26 @@ do
 	'
 done
 
+test_expect_success "--grep accepts a pattern beginning with --" '
+        test_commit --no-tag --missing-only &&
+        commit=$(git rev-parse HEAD) &&
+        echo "$commit" >expect &&
+        git rev-list --grep=--missing-only HEAD >actual &&
+        test_cmp expect actual &&
+        git rev-list --grep --missing-only HEAD >actual &&
+        test_cmp expect actual
+'
+
+test_expect_success "--grep does not trigger --exclude-promisor-objects in early scan" '
+        test_commit --no-tag --exclude-promisor-objects &&
+        commit=$(git rev-parse HEAD) &&
+        echo "$commit" >expect &&
+        git rev-list --grep=--exclude-promisor-objects --missing=print HEAD >actual &&
+        test_cmp expect actual &&
+        git rev-list --grep --exclude-promisor-objects --missing=print HEAD >actual &&
+        test_cmp expect actual
+'
+
 test_expect_success "--missing-only requires --missing=print or --missing=print-info" '
 	test_must_fail git rev-list --missing-only --objects HEAD 2>err &&
 	test_grep "requires --missing=print" err
-- 
2.53.0