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From: Siddharth Asthana <siddharthasthana31@gmail•com>
To: git@vger•kernel.org
Cc: christian.couder@gmail•com, ps@pks•im, newren@gmail•com,
	gitster@pobox•com, phillip.wood123@gmail•com,
	phillip.wood@dunelm•org.uk, karthik.188@gmail•com,
	johannes.schindelin@gmx•de, toon@iotcl•com,
	Siddharth Asthana <siddharthasthana31@gmail•com>
Subject: [PATCH v3 0/2] replay: add --revert mode to reverse commit changes
Date: Thu, 19 Feb 2026 05:12:13 +0530	[thread overview]
Message-ID: <20260218234215.89326-1-siddharthasthana31@gmail.com> (raw)
In-Reply-To: <20251202201611.22137-1-siddharthasthana31@gmail.com>

The `git replay` command performs server-side history rewriting without
requiring a working tree. While it currently supports cherry-picking
commits (--advance) and rebasing (--onto), it lacks the ability to
revert them.

At GitLab, we use replay in Gitaly for efficient server-side operations
on bare repositories. Adding revert functionality enables us to reverse
problematic commits directly on the server, eliminating client-side
roundtrips and reducing network overhead.

The implementation follows the same approach as sequencer.c where
cherry-pick and revert are the same merge operation but with swapped
arguments. For cherry-pick we merge(ancestor=parent, ours=current,
theirs=commit), while for revert we merge(ancestor=commit, ours=current,
theirs=parent). By swapping the base and pickme trees when calling
merge_incore_nonrecursive(), we effectively reverse the diff direction.

The series is structured as follows:

Patch 1 extracts the revert message formatting logic into a shared
sequencer_format_revert_header() function, eliminating code duplication
between sequencer.c and the upcoming replay code. This follows Junio's
suggestion to split the changes.

Patch 2 adds the --revert <branch> mode to git replay. Following the
architectural pattern suggested by Elijah and Phillip, --revert is a
standalone mode (like --onto and --advance) that takes a branch argument
and updates that branch with the revert commits.

The series is based on top of 864f55e190 (The second batch, 2026-02-07).

CI: https://gitlab.com/gitlab-org/git/-/pipelines/2329880894
The Windows CI failures (t4041, t4059, t4060, t4205, t6006) are
pre-existing infrastructure issues (missing iconv, submodule pathspec
errors) unrelated to this series.

Signed-off-by: Siddharth Asthana <siddharthasthana31@gmail•com>
---
Changes in v3:
- Rebased on top of the latest upstream which refactored replay into
  a library (replay.c / replay.h). The --revert logic now lives in
  replay.c alongside the existing pick logic, while builtin/replay.c
  is a thin CLI wrapper.
- sequencer_format_revert_header() now takes an optional oid parameter
  so it can handle the full commit reference internally, per Patrick's
  suggestion about refer_to_commit()
- Removed now-unused `orig_subject` variable in do_pick_commit()
- Switched to die_for_incompatible_opt3() for --onto/--advance/--revert
  mutual exclusivity, per Patrick
- --contained now just checks "die(_("--contained requires --onto"))"
  instead of going through die_for_incompatible_opt2, per Phillip
- Added BUG() guards for unhandled replay_mode values, per Patrick
- Merged the separate advance/revert ref update blocks into one
- author is set to NULL for revert commits so commit_tree_extended()
  picks up the current user, per Phillip
- Factored out common --advance/--revert branch validation into a
  set_up_branch_mode() helper, per Phillip
- Doc wording fixes: "reverted commits", "they are prefixed",
  "hash" instead of "SHA", per Phillip
- Tests now reuse topic4 instead of creating new branches, use heredoc
  for test_commit_message, and the reflog check is folded into the
  main revert test
- Added tests for bare repo revert, error cases (argument validation,
  multiple sources)
- Link to v2: https://public-inbox.org/git/20251202201611.22137-1-siddharthasthana31@gmail.com/t/#u
- Link to v1: https://public-inbox.org/git/20251125170056.34489-1-siddharthasthana31@gmail.com/t/#u

---
 Documentation/git-replay.adoc |  37 +++++++-
 builtin/replay.c              |  25 ++++--
 replay.c                      | 162 ++++++++++++++++++++++++----------
 replay.h                      |  11 ++-
 sequencer.c                   |  47 ++++++----
 sequencer.h                   |  11 +++
 t/t3650-replay-basics.sh      | 107 ++++++++++++++++++++--
 7 files changed, 319 insertions(+), 81 deletions(-)

Siddharth Asthana (2):
  sequencer: extract revert message formatting into shared function
  replay: add --revert mode to reverse commit changes

Range-diff versus v2:

1:  bfd75484b4 ! 1:  9d686bcdfe sequencer: extract revert message formatting into shared function
    @@ Commit message
         Extract this logic into a new sequencer_format_revert_header() function
         that can be shared. The function handles both regular reverts ("Revert
         "<subject>"") and revert-of-revert cases ("Reapply "<subject>"").
    +    When an oid is provided, the function appends the full commit hash and
    +    period; otherwise the caller should append the commit reference.
    +
         Update do_pick_commit() to use the new helper, eliminating code
         duplication while preserving the special handling for commit_use_reference.
     
         Signed-off-by: Siddharth Asthana <siddharthasthana31@gmail•com>
     
      ## sequencer.c ##
    +@@ sequencer.c: static int do_pick_commit(struct repository *r,
    + 	 */
    + 
    + 	if (command == TODO_REVERT) {
    +-		const char *orig_subject;
    +-
    + 		base = commit;
    + 		base_label = msg.label;
    + 		next = parent;
     @@ sequencer.c: static int do_pick_commit(struct repository *r,
      		if (opts->commit_use_reference) {
      			strbuf_commented_addf(&ctx->message, comment_line_str,
     @@ sequencer.c: static int do_pick_commit(struct repository *r,
     -			strbuf_addstr(&ctx->message, "Revert \"");
     -			strbuf_addstr(&ctx->message, msg.subject);
     -			strbuf_addstr(&ctx->message, "\"\n");
    -+			sequencer_format_revert_header(&ctx->message, msg.subject);
    ++			sequencer_format_revert_header(&ctx->message, msg.subject, NULL);
      		}
     -		strbuf_addstr(&ctx->message, "\nThis reverts commit ");
      		refer_to_commit(opts, &ctx->message, commit);
    @@ sequencer.c: int sequencer_pick_revisions(struct repository *r,
      	return res;
      }
      
    -+void sequencer_format_revert_header(struct strbuf *out, const char *orig_subject)
    ++void sequencer_format_revert_header(struct strbuf *out,
    ++				    const char *orig_subject,
    ++				    const struct object_id *oid)
     +{
     +	const char *revert_subject;
     +
    @@ sequencer.c: int sequencer_pick_revisions(struct repository *r,
     +	}
     +
     +	strbuf_addstr(out, "\nThis reverts commit ");
    ++	if (oid) {
    ++		strbuf_addstr(out, oid_to_hex(oid));
    ++		strbuf_addstr(out, ".\n");
    ++	}
     +}
     +
      void append_signoff(struct strbuf *msgbuf, size_t ignore_footer, unsigned flag)
    @@ sequencer.h: int sequencer_determine_whence(struct repository *r, enum commit_wh
      int sequencer_get_update_refs_state(const char *wt_dir, struct string_list *refs);
      
     +/*
    -+ * Formats a revert commit message header following standard Git conventions.
    ++ * Formats a revert commit message following standard Git conventions.
     + * Handles both regular reverts ("Revert \"<subject>\"") and revert of revert
    -+ * cases ("Reapply \"<subject>\""). Adds "This reverts commit " at the end.
    -+ * The caller should append the commit OID after calling this function.
    ++ * cases ("Reapply \"<subject>\""). Adds "This reverts commit <oid>." if oid
    ++ * is provided, otherwise just adds "This reverts commit " and the caller
    ++ * should append the commit reference.
     + */
    -+void sequencer_format_revert_header(struct strbuf *out, const char *orig_subject);
    ++void sequencer_format_revert_header(struct strbuf *out,
    ++				    const char *orig_subject,
    ++				    const struct object_id *oid);
     +
      #endif /* SEQUENCER_H */
2:  a2f99bc8c2 < -:  ---------- replay: add --revert mode to reverse commit changes
-:  ---------- > 2:  a8eae7b802 replay: add --revert mode to reverse commit changes


base-commit: 864f55e1906897b630333675a52874c0fec2a45c

Thanks
- Siddharth

  parent reply	other threads:[~2026-02-18 23:42 UTC|newest]

Thread overview: 96+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-25 17:00 [PATCH 0/1] replay: add --revert option to reverse commit changes Siddharth Asthana
2025-11-25 17:00 ` [PATCH 1/1] " Siddharth Asthana
2025-11-25 19:22   ` Junio C Hamano
2025-11-25 19:30     ` Junio C Hamano
2025-11-25 19:39       ` Junio C Hamano
2025-11-25 20:06         ` Junio C Hamano
2025-11-26 19:31           ` Siddharth Asthana
2025-11-26 19:28         ` Siddharth Asthana
2025-11-26 19:26     ` Siddharth Asthana
2025-11-26 21:13       ` Junio C Hamano
2025-11-27 19:23         ` Siddharth Asthana
2025-11-26 11:10   ` Phillip Wood
2025-11-26 17:35     ` Elijah Newren
2025-11-26 18:41       ` Junio C Hamano
2025-11-26 21:17         ` Junio C Hamano
2025-11-26 23:06           ` Elijah Newren
2025-11-26 23:14             ` Junio C Hamano
2025-11-26 23:57               ` Elijah Newren
2025-11-26 19:50       ` Siddharth Asthana
2025-11-26 19:39     ` Siddharth Asthana
2025-11-27 16:21       ` Phillip Wood
2025-11-27 19:24         ` Siddharth Asthana
2025-11-25 17:25 ` [PATCH 0/1] " Johannes Schindelin
2025-11-25 18:02   ` Junio C Hamano
2025-11-26 19:18   ` Siddharth Asthana
2025-11-26 21:04     ` Junio C Hamano
2025-11-27 19:21       ` Siddharth Asthana
2025-11-27 20:17         ` Junio C Hamano
2025-11-28  8:07         ` Elijah Newren
2025-11-28  8:24           ` Siddharth Asthana
2025-11-28 16:35             ` Junio C Hamano
2025-11-28 17:07               ` Elijah Newren
2025-11-28 20:50                 ` Junio C Hamano
2025-11-28 22:03                   ` Elijah Newren
2025-11-29  5:59                     ` Junio C Hamano
2025-12-02 20:16 ` [PATCH v2 0/2] replay: add --revert mode " Siddharth Asthana
2025-12-02 20:16   ` [PATCH v2 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2025-12-05 11:33     ` Patrick Steinhardt
2025-12-07 23:00       ` Siddharth Asthana
2025-12-08  7:07         ` Patrick Steinhardt
2026-02-11 13:03           ` Toon Claes
2026-02-11 13:40             ` Patrick Steinhardt
2026-02-11 15:23             ` Kristoffer Haugsbakk
2026-02-11 17:41               ` Junio C Hamano
2026-02-18 22:53             ` Siddharth Asthana
2025-12-02 20:16   ` [PATCH v2 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
2025-12-05 11:33     ` Patrick Steinhardt
2025-12-07 23:03       ` Siddharth Asthana
2025-12-16 16:23     ` Phillip Wood
2026-02-18 23:42   ` Siddharth Asthana [this message]
2026-02-18 23:42     ` [PATCH v3 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2026-02-20 17:01       ` Toon Claes
2026-02-25 21:53         ` Junio C Hamano
2026-03-06  4:55           ` Siddharth Asthana
2026-03-06  4:31         ` Siddharth Asthana
2026-02-26 14:27       ` Phillip Wood
2026-03-06  5:00         ` Siddharth Asthana
2026-02-18 23:42     ` [PATCH v3 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
2026-02-20 17:35       ` Toon Claes
2026-02-20 20:23         ` Junio C Hamano
2026-02-23  9:13         ` Christian Couder
2026-02-23 11:23           ` Toon Claes
2026-03-06  5:05         ` Siddharth Asthana
2026-02-26 14:45       ` Phillip Wood
2026-03-06  5:28         ` Siddharth Asthana
2026-03-06 15:52           ` Phillip Wood
2026-03-06 16:20             ` Siddharth Asthana
2026-03-13  5:40     ` [PATCH v4 0/2] " Siddharth Asthana
2026-03-13  5:40       ` [PATCH v4 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2026-03-13 15:53         ` Junio C Hamano
2026-03-16 19:12           ` Toon Claes
2026-03-16 16:57         ` Phillip Wood
2026-03-13  5:40       ` [PATCH v4 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
2026-03-16 16:57         ` Phillip Wood
2026-03-16 19:52         ` Toon Claes
2026-03-17 10:11           ` Phillip Wood
2026-03-16 16:59       ` [PATCH v4 0/2] " Phillip Wood
2026-03-16 19:53       ` Toon Claes
2026-03-24 22:03       ` [PATCH v5 " Siddharth Asthana
2026-03-24 22:04         ` [PATCH v5 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2026-03-24 22:04         ` [PATCH v5 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
2026-03-25  6:29           ` Junio C Hamano
2026-03-25 15:10             ` Toon Claes
2026-03-25 15:38               ` Siddharth Asthana
2026-03-25 16:44               ` Phillip Wood
2026-03-25 15:36             ` Siddharth Asthana
2026-03-25 20:23         ` [PATCH v6 0/2] " Siddharth Asthana
2026-03-25 20:23           ` [PATCH v6 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2026-03-25 20:23           ` [PATCH v6 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
2026-03-28  4:33             ` Tian Yuchen
2026-03-29 16:17               ` Siddharth Asthana
2026-03-30 17:23                 ` Tian Yuchen
2026-03-31  8:08                   ` Toon Claes
2026-03-31  8:11                 ` Toon Claes
2026-03-25 20:23           ` [PATCH v6 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2026-03-25 20:23           ` [PATCH v6 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana

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