From: Phillip Wood Date: Thu, 27 Aug 2026 15:19:23 GMT Subject: Re: [PATCH v2 2/3] commit: refuse to amend during conflict resolution Message-ID: In-Reply-To: <4a1461e52767227d9475de13cf250484f8ecd271.1787792534.git.gitgitgadget@gmail.com> Hi Elijah On 27/08/2026 02:02, Elijah Newren via GitGitGadget wrote: > From: Elijah Newren > > diff --git a/builtin/commit.c b/builtin/commit.c > index 0d908d72bb..4a6054aae0 100644 > --- a/builtin/commit.c > +++ b/builtin/commit.c > @@ -1326,15 +1326,30 @@ static int parse_and_validate_options(int argc, const char *argv[], > use_editor = 0; > > /* Sanity check options */ > - if (amend && !current_head) > - die(_("You have nothing to amend.")); > - if (amend && whence != FROM_COMMIT) { > - if (whence == FROM_MERGE) > + if (amend) { > + if (!current_head) > + die(_("You have nothing to amend.")); > + /* > + * Refuse to amend in the middle of any operation that is > + * meant to record its result as a new commit on top of HEAD > + * rather than by rewriting HEAD. > + */ > + switch (sequencer_ongoing_operation(s->repo, whence)) { > + case ONGOING_NONE: > + break; > + case ONGOING_MERGE: > die(_("You are in the middle of a merge -- cannot amend.")); > - else if (is_from_cherry_pick(whence)) > + case ONGOING_CHERRY_PICK: > die(_("You are in the middle of a cherry-pick -- cannot amend.")); For rebase we distinguish between a conflict and a commit that becomes empty, but we don't do that for a cherry-pick. That's an existing problem though, not something we necessarily need to address in this series. Moving the detection to a separate function and using an enum here is much nicer than the previous version. > diff --git a/sequencer.c b/sequencer.c > index 65afd100d9..bd4a724410 100644 > --- a/sequencer.c > +++ b/sequencer.c > @@ -6966,6 +6966,71 @@ int sequencer_determine_whence(struct repository *r, enum commit_whence *whence) > return 0; > } > > +enum ongoing_operation sequencer_ongoing_operation(struct repository *r, > + enum commit_whence whence) > +{ > [...] > + /* > + * In the middle of a rebase that stopped for conflict resolution? > + * The apply backend only ever stops for conflicts, so the presence > + * of its state directory is enough. The merge backend writes > + * stopped-sha whenever it hands control back to the user, but omits > + * `amend` unless it stopped with HEAD already pointing at the commit > + * to be amended (a clean edit/reword stop); its absence therefore > + * marks a conflicted stop. > + */ > + path = repo_git_path(r, "rebase-apply"); > + found = file_exists(path); > + free(path); > + if (!found) { > + char *stopped_sha = repo_git_path(r, "rebase-merge/stopped-sha"); > + char *amend_marker = repo_git_path(r, "rebase-merge/amend"); > + > + found = file_exists(stopped_sha) && !file_exists(amend_marker); The sequencer defines rebase_path_stoppend_sha() and rebase_path_amend() so we can avoid having to hard code these paths throughout the code. Apart from that this all looks good to me. Thanks Phillip > + free(stopped_sha); > + free(amend_marker); > + } > + if (found) > + return ONGOING_REBASE_CONFLICT; > + > + return ONGOING_NONE; > +} > + > int sequencer_get_update_refs_state(const char *wt_dir, > struct string_list *refs) > { > diff --git a/sequencer.h b/sequencer.h > index 64a9c7fb1b..3a4bd97db1 100644 > --- a/sequencer.h > +++ b/sequencer.h > @@ -277,6 +277,29 @@ int sequencer_get_last_command(struct repository* r, > enum replay_action *action); > int sequencer_determine_whence(struct repository *r, enum commit_whence *whence); > > +/* > + * An in-progress operation that records its result (often a conflict > + * resolution) as a new commit on top of HEAD, during which amending > + * HEAD via "git commit --amend" is almost always a mistake. > + */ > +enum ongoing_operation { > + ONGOING_NONE = 0, > + ONGOING_MERGE, > + ONGOING_CHERRY_PICK, > + ONGOING_REBASE_EMPTY, > + ONGOING_REVERT, > + ONGOING_AM, > + ONGOING_REBASE_CONFLICT > +}; > + > +/* > + * Return which in-progress operation, if any, is underway; see enum > + * ongoing_operation. 'whence' is the origin already computed for the > + * pending commit. > + */ > +enum ongoing_operation sequencer_ongoing_operation(struct repository *r, > + enum commit_whence whence); > + > /** > * Append the set of ref-OID pairs that are currently stored for the 'git > * rebase --update-refs' feature if such a rebase is currently happening. > diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh > index 1e78dbfd90..7cf06e5f9a 100755 > --- a/t/t3404-rebase-interactive.sh > +++ b/t/t3404-rebase-interactive.sh > @@ -1884,6 +1884,93 @@ test_expect_success 'correct error message for commit --amend after empty pick' > test_grep "resolving a commit that became empty -- cannot amend." err > ' > > +test_expect_success 'commit --amend is refused at a rebase conflict stop' ' > + test_when_finished "git rebase --abort" && > + git checkout --detach conflict-branch && > + ( > + set_fake_editor && > + FAKE_LINES="1 3" && > + export FAKE_LINES && > + test_must_fail git rebase -i A > + ) && > + test_path_is_file .git/rebase-merge/patch && > + test_path_is_missing .git/rebase-merge/amend && > + echo resolved >conflict && > + git add conflict && > + test_must_fail git commit --amend --no-edit 2>err && > + test_grep "You are resolving conflicts during a rebase -- cannot amend" err > +' > + > +test_expect_success 'commit --amend is refused when an "edit" pick conflicts' ' > + test_when_finished "git rebase --abort" && > + git checkout --detach conflict-branch && > + ( > + set_fake_editor && > + FAKE_LINES="1 edit 3" && > + export FAKE_LINES && > + test_must_fail git rebase -i A > + ) && > + test_path_is_file .git/rebase-merge/patch && > + test_path_is_missing .git/rebase-merge/amend && > + echo resolved >conflict && > + git add conflict && > + test_must_fail git commit --amend --no-edit 2>err && > + test_grep "You are resolving conflicts during a rebase -- cannot amend" err > +' > + > +test_expect_success 'commit --amend is allowed at a rebase edit stop' ' > + test_when_finished "git rebase --abort" && > + git checkout --detach no-conflict-branch && > + ( > + set_fake_editor && > + FAKE_LINES="edit 1 2 3 4" && > + export FAKE_LINES && > + git rebase -i A > + ) && > + test_path_is_file .git/rebase-merge/amend && > + echo tweak >fileJ && > + git add fileJ && > + git commit --amend --no-edit > +' > + > +test_expect_success 'commit --amend is allowed at a rebase break stop' ' > + test_when_finished "git rebase --abort" && > + git checkout --detach no-conflict-branch && > + ( > + set_fake_editor && > + FAKE_LINES="break 1 2 3 4" && > + export FAKE_LINES && > + git rebase -i A > + ) && > + test_must_fail git rev-parse --verify REBASE_HEAD && > + echo tweak >fileJ && > + git add fileJ && > + git commit --amend --no-edit > +' > + > +test_expect_success 'commit --amend is refused at an apply-backend conflict stop' ' > + test_when_finished "rm -rf apply-backend" && > + test_create_repo apply-backend && > + ( > + cd apply-backend && > + test_commit base file && > + git branch -M mainline && > + test_commit upstream file upstream && > + git checkout -b side mainline~1 && > + test_commit conflicting file side && > + test_commit unrelated other && > + test_must_fail git rebase --apply mainline && > + # the apply backend only ever stops for conflicts, and > + # leaves HEAD on the previously-applied commit > + test_path_is_dir .git/rebase-apply && > + test_path_is_missing .git/rebase-apply/applying && > + echo resolved >file && > + git add file && > + test_must_fail git commit --amend --no-edit 2>err && > + test_grep "You are resolving conflicts during a rebase -- cannot amend" err > + ) > +' > + > test_expect_success 'todo has correct onto hash' ' > GIT_SEQUENCE_EDITOR=cat git rebase -i no-conflict-branch~4 no-conflict-branch >actual && > onto=$(git rev-parse --short HEAD~4) && > diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh > index 44596cb1e8..42de398f76 100755 > --- a/t/t3507-cherry-pick-conflict.sh > +++ b/t/t3507-cherry-pick-conflict.sh > @@ -364,6 +364,17 @@ test_expect_success 'failed revert sets REVERT_HEAD' ' > test_cmp_rev picked REVERT_HEAD > ' > > +test_expect_success 'commit --amend of revert fails' ' > + pristine_detach initial && > + > + test_must_fail git revert picked && > + echo resolved >foo && > + git add foo && > + test_must_fail git commit --amend 2>err && > + > + test_grep "in the middle of a revert -- cannot amend." err > +' > + > test_expect_success 'successful revert does not set REVERT_HEAD' ' > pristine_detach base && > git revert base && > diff --git a/t/t4151-am-abort.sh b/t/t4151-am-abort.sh > index 8e1ecf8a68..9313a074b2 100755 > --- a/t/t4151-am-abort.sh > +++ b/t/t4151-am-abort.sh > @@ -63,6 +63,17 @@ do > > done > > +test_expect_success 'commit --amend during a failed am fails' ' > + git reset --hard initial && > + cp file-2-expect file-2 && > + test_must_fail git am 000[1245]-*.patch && > + echo resolved >file-1 && > + git add file-1 && > + test_must_fail git commit --amend 2>err && > + test_grep "in the middle of an am session -- cannot amend." err && > + git am --abort > +' > + > test_expect_success 'am -3 --skip removes otherfile-4' ' > git reset --hard initial && > test_must_fail git am -3 0003-*.patch &&