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[PATCH v2 1/2] revision.c: implement --reverse=before for walks

From
Mirko Faina <mroik@delayed.space>
Date
Apr 22, 2026, 00:28 UTC
Message-ID
<20260422002840.303477-5-mroik@delayed.space>
In-Reply-To
<20260418164736.2367523-2-mroik@delayed.space>

In a revision walk `--reverse` can only be applied after any commit limiting option. This makes getting a limited amount of commits from the tail impossible. E.g.

    git log --reverse --max-count=3

Some would expect this to give back the first 3 commits of the project. Instead it returns the last 3 but in reversed order.

Teach `get_revision()` to accpet an argument `(after|before)` from the CLI, and apply the reversal before or after the commit limiting options based on this argument. If no argument is provided default to the current behaviour, applying `--reverse` after the commit limiting options.

Signed-off-by: Mirko Faina <mroik@delayed.space>
---
 Documentation/rev-list-options.adoc | 14 ++++--
 revision.c                          | 31 ++++++++++++--
 revision.h                          |  8 +++-
 t/t4202-log.sh                      | 66 +++++++++++++++++++++++++++++
 4 files changed, 111 insertions(+), 8 deletions(-)
diff --git a/Documentation/rev-list-options.adoc b/Documentation/rev-list-options.adoc
index 2d195a1474..7244e85108 100644
--- a/Documentation/rev-list-options.adoc
+++ b/Documentation/rev-list-options.adoc
@@ -914,10 +914,16 @@ With `--topo-order`, they would show 8 6 5 3 7 4 2 1 (or 8 7 4 2 6 5
 avoid showing the commits from two parallel development track mixed
 together.
 
-`--reverse`::
-	Output the commits chosen to be shown (see 'Commit Limiting'
-	section above) in reverse order. Cannot be combined with
-	`--walk-reflogs`.
+`--[no-]reverse[=(after|before)]`::
+	Accepts `after` or `before`. Cannot be combined with
+	`--walk-reflogs`. If `after`, output the commits chosen to be
+	shown (see 'Commit Limiting' section above) in reverse order. If
+	`before`, reverse the commits before filtering with `Commit
+	Limiting` options. This option can be used multiple times, last
+	one is applied. When the argument for `--reverse` is omitted, if
+	the current state is in no reverse, it defaults to `after`. If
+	it is in any reversed state, it restores the original ordering
+	by removing the reverse state.
 endif::git-shortlog[]
 
 ifndef::git-shortlog[]
diff --git a/revision.c b/revision.c
index 599b3a66c3..d581f5e38e 100644
--- a/revision.c
+++ b/revision.c
@@ -2686,7 +2686,16 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 			git_log_output_encoding = xstrdup("");
 		return argcount;
 	} else if (!strcmp(arg, "--reverse")) {
-		revs->reverse ^= 1;
+		revs->reverse = !revs->reverse;
+	} else if (skip_prefix(arg, "--reverse=", &optarg)) {
+		if (!strcmp(optarg, "after"))
+			revs->reverse = REVERSE_AFTER;
+		else if(!strcmp(optarg, "before"))
+			revs->reverse = REVERSE_BEFORE;
+		else
+			die(_("unknown value for --reverse: %s"), optarg);
+	} else if (!strcmp(arg, "--no-reverse")) {
+		revs->reverse = NO_REVERSE;
 	} else if (!strcmp(arg, "--children")) {
 		revs->children.name = "children";
 		revs->limited = 1;
@@ -4525,19 +4534,35 @@ struct commit *get_revision(struct rev_info *revs)
 {
 	struct commit *c;
 	struct commit_list *reversed;
+	int max_count = revs->max_count;
+
+	if (revs->reverse && !revs->reverse_output_stage) {
+		if (revs->reverse == 3) {
+			BUG("allowed values for reverse are 0, 1 and 2");
+			revs->reverse = 1;
+		}
+
+		if (revs->reverse == REVERSE_BEFORE)
+			revs->max_count = -1;
 
-	if (revs->reverse) {
 		reversed = NULL;
 		while ((c = get_revision_internal(revs)))
 			commit_list_insert(c, &reversed);
 		commit_list_free(revs->commits);
 		revs->commits = reversed;
-		revs->reverse = 0;
 		revs->reverse_output_stage = 1;
+
+		if (revs->reverse == REVERSE_BEFORE)
+			revs->max_count = max_count;
 	}
 
 	if (revs->reverse_output_stage) {
+		if (revs->reverse == REVERSE_BEFORE && revs->max_count == 0)
+			return NULL;
+
 		c = pop_commit(&revs->commits);
+		if (revs->reverse == REVERSE_BEFORE)
+			revs->max_count--;
 		if (revs->track_linear)
 			revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
 		return c;
diff --git a/revision.h b/revision.h
index 584f1338b5..02881577dc 100644
--- a/revision.h
+++ b/revision.h
@@ -121,6 +121,12 @@ struct ref_exclusions {
 struct oidset;
 struct topo_walk_info;
 
+enum rev_reverse {
+	NO_REVERSE = 0,
+	REVERSE_AFTER = 1,
+	REVERSE_BEFORE = 2,
+};
+
 struct rev_info {
 	/* Starting list */
 	struct commit_list *commits;
@@ -167,6 +173,7 @@ struct rev_info {
 			ignore_missing_links:1;
 
 	/* Traversal flags */
+	enum rev_reverse reverse:2;
 	unsigned int	dense:1,
 			prune:1,
 			no_walk:1,
@@ -196,7 +203,6 @@ struct rev_info {
 			rewrite_parents:1,
 			print_parents:1,
 			show_decorations:1,
-			reverse:1,
 			reverse_output_stage:1,
 			cherry_pick:1,
 			cherry_mark:1,
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 05cee9e41b..3bfe2c99b8 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -1882,6 +1882,72 @@ test_expect_success 'log --graph with --name-status' '
 	test_cmp_graph --name-status tangle..reach
 '
 
+cat >expect <<-\EOF
+c3f451c Merge tag 'reach'
+046b221 to remove
+EOF
+
+test_expect_success 'log --reverse --oneline --max-count=2' '
+	test_when_finished git reset --hard HEAD~1 &&
+	touch to_remove &&
+	git add to_remove &&
+	git commit -m "to remove" &&
+	git log --reverse --oneline --max-count=2 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'log --reverse --reverse --reverse --oneline --max-count=2' '
+	test_when_finished git reset --hard HEAD~1 &&
+	touch to_remove &&
+	git add to_remove &&
+	git commit -m "to remove" &&
+	git log --reverse --reverse --reverse --oneline --max-count=2 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'log --reverse=after --oneline --max-count=2' '
+	test_when_finished git reset --hard HEAD~1 &&
+	touch to_remove &&
+	git add to_remove &&
+	git commit -m "to remove" &&
+	git log --reverse=after --oneline --max-count=2 >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<-\EOF
+3a2fdcb initial
+f7dab8e second
+EOF
+
+test_expect_success 'log --reverse=before --oneline --max-count=2' '
+	test_when_finished rm actual &&
+	git log --reverse=before --oneline --max-count=2 >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<-\EOF
+046b221 to remove
+c3f451c Merge tag 'reach'
+EOF
+
+test_expect_success 'log --reverse --reverse --oneline --max-count=2' '
+	test_when_finished git reset --hard HEAD~1 &&
+	touch to_remove &&
+	git add to_remove &&
+	git commit -m "to remove" &&
+	git log --reverse --reverse --oneline --max-count=2 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'log --reverse --no-reverse --oneline --max-count=2' '
+	test_when_finished git reset --hard HEAD~1 &&
+	touch to_remove &&
+	git add to_remove &&
+	git commit -m "to remove" &&
+	git log --reverse --no-reverse --oneline --max-count=2 >actual &&
+	test_cmp expect actual
+'
+
 cat >expect <<-\EOF
 * reach
 |

-- 
2.54.0
Previous: Mirko FainaNext: Jeff King
Message 61 of 63 in “revision.c: implement --reverse=before for walks”
  1. revision.c: implement --reverse=before for walksMirko Faina, Apr 18, 2026
  2. Tian YuchenApr 18, 2026
  3. Mirko FainaApr 18, 2026
  4. Mirko FainaApr 18, 2026
  5. Junio C HamanoApr 20, 2026
  6. Tian YuchenApr 20, 2026
  7. Mirko FainaApr 20, 2026
  8. Ben KnobleApr 19, 2026
  9. Mirko FainaApr 19, 2026
  10. D. Ben KnobleApr 19, 2026
  11. Mirko FainaApr 19, 2026
  12. Jeff KingApr 20, 2026
  13. Mirko FainaApr 20, 2026
  14. Mirko FainaApr 20, 2026
  15. Jeff KingApr 21, 2026
  16. D. Ben KnobleApr 22, 2026
  17. Mirko FainaApr 22, 2026
  18. Jeff KingApr 20, 2026
  19. Mirko FainaApr 20, 2026
  20. 0/2 revision.c: implement --reverse=before for walksMirko Faina, Apr 22, 2026
  21. Mirko FainaApr 22, 2026
  22. 0/2 revision.c: implement --reverse=before for walksMirko Faina, Apr 23, 2026
  23. 2/2 revision.c: reduce memory usage on reverse beforeMirko Faina, Apr 23, 2026
  24. 1/2 revision.c: implement --reverse=before for walksMirko Faina, Apr 23, 2026
  25. Junio C HamanoApr 28, 2026
  26. 0/2 revision.c: implement --reverse=before for walksMirko Faina, Apr 27, 2026
  27. 2/2 revision.c: reduce memory usage on reverse beforeMirko Faina, Apr 27, 2026
  28. Junio C HamanoApr 28, 2026
  29. 1/2 revision.c: implement --reverse=before for walksMirko Faina, Apr 27, 2026
  30. Junio C HamanoApr 27, 2026
  31. Johannes SixtApr 27, 2026
  32. Junio C HamanoApr 27, 2026
  33. Chris TorekApr 27, 2026
  34. Mirko FainaApr 27, 2026
  35. Junio C HamanoApr 28, 2026
  36. Junio C HamanoApr 28, 2026
  37. revision.c: implement --max-count-oldestMirko Faina, Apr 30, 2026
  38. Junio C HamanoMay 4, 2026
  39. Mirko FainaMay 4, 2026
  40. revision.c: implement --max-count-oldestMirko Faina, May 5, 2026
  41. Johannes SixtMay 6, 2026
  42. Mirko FainaMay 6, 2026
  43. Junio C HamanoMay 7, 2026
  44. Mirko FainaMay 8, 2026
  45. Jean-Noël AVILAMay 9, 2026
  46. Mirko FainaMay 10, 2026
  47. Junio C HamanoMay 9, 2026
  48. Mirko FainaMay 10, 2026
  49. revision.c: implement --max-count-oldestMirko Faina, May 15, 2026
  50. revision.c: implement --max-count-oldestMirko Faina, May 19, 2026
  51. Mirko FainaMay 19, 2026
  52. Junio C HamanoMay 20, 2026
  53. Mirko FainaMay 20, 2026
  54. revision.c: implement --max-count-oldestJunio C Hamano, Jun 1, 2026
  55. Mirko FainaJun 2, 2026
  56. Junio C HamanoMay 19, 2026
  57. Mirko FainaMay 19, 2026
  58. Junio C HamanoMay 9, 2026
  59. Mirko FainaMay 10, 2026
  60. 2/2 revision.c: reduce memory usage on reverse beforeMirko Faina, Apr 22, 2026
  61. 1/2 revision.c: implement --reverse=before for walksMirko Faina, Apr 22, 2026
  62. Jeff KingApr 22, 2026
  63. Mirko FainaApr 22, 2026

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