From: Phillip Wood Date: Thu, 22 Feb 2024 16:35:29 GMT Subject: Re: [PATCH v2 6/8] cherry-pick: decouple `--allow-empty` and `--keep-redundant-commits` Message-ID: <3f276e10-7b03-4480-a157-47a7648e7f19@gmail.com> In-Reply-To: <20240210074859.552497-7-brianmlyles@gmail.com> Hi Brian On 10/02/2024 07:43, Brian Lyles wrote: > As noted in the git-cherry-pick(1) docs, `--keep-redundant-commits` > implies `--allow-empty`, despite the two having distinct, > non-overlapping meanings: > > - `allow_empty` refers specifically to commits which start empty, as > indicated by the documentation for `--allow-empty` within > git-cherry-pick(1): > > "Note also, that use of this option only keeps commits that were > initially empty (i.e. the commit recorded the same tree as its > parent). Commits which are made empty due to a previous commit are > dropped. To force the inclusion of those commits use > --keep-redundant-commits." > > - `keep_redundant_commits` refers specifically to commits that do not > start empty, but become empty due to the content already existing in > the target history. This is indicated by the documentation for > `--keep-redundant-commits` within git-cherry-pick(1): > > "If a commit being cherry picked duplicates a commit already in the > current history, it will become empty. By default these redundant > commits cause cherry-pick to stop so the user can examine the commit. > This option overrides that behavior and creates an empty commit > object. Implies --allow-empty." > > This implication of `--allow-empty` therefore seems incorrect: One > should be able to keep a commit that becomes empty without also being > forced to pick commits that start as empty. However, the following > series of commands results in both the commit that became empty and the > commit that started empty being picked, despite only > `--keep-redundant-commits` being specified: > > git init > echo "a" >test > git add test > git commit -m "Initial commit" > echo "b" >test > git commit -am "a -> b" > git commit --allow-empty -m "empty" > git cherry-pick --keep-redundant-commits HEAD^ HEAD > > The same cherry-pick with `--allow-empty` would fail on the redundant > commit, and with neither option would fail on the empty commit. > > Do not imply `--allow-empty` when using `--keep-redundant-commits` with > git-cherry-pick(1). > > Signed-off-by: Brian Lyles > --- > > This is the second half of the first commit[1] in v1, which has now been > split up. > > This commit proposes a breaking change, albeit one that seems correct > and relatively minor to me. If this change is deemed too controversial, > I am prepared to drop it from the series. See Junio's[2] and > Phillip's[3] comments on v1 for additional context. I agree that if we were starting from scratch there would be no reason to tie --apply-empty and --keep-redundant-commits together but I'm not sure it is worth the disruption of changing it now. We're about to add empty=keep which won't imply --allow-empty for anyone who wants that behavior and I still tend to think the practical effect of implying --allow-empty with --keep-redundant-commits is largely beneficial as I'm skeptical that users want to keep commits that become empty but not the ones that started empty. Best Wishes Phillip > [1]: https://lore.kernel.org/git/20240119060721.3734775-2-brianmlyles@gmail.com/ > [2]: https://lore.kernel.org/git/xmqqy1cfnca7.fsf@gitster.g/ > [3]: https://lore.kernel.org/git/8ff4650c-f84f-41bd-a46c-3b845ff29b70@gmail.com/ > > Documentation/git-cherry-pick.txt | 10 +++++++--- > builtin/revert.c | 4 ---- > t/t3505-cherry-pick-empty.sh | 6 ++++++ > 3 files changed, 13 insertions(+), 7 deletions(-) > > diff --git a/Documentation/git-cherry-pick.txt b/Documentation/git-cherry-pick.txt > index fdcad3d200..c88bb88822 100644 > --- a/Documentation/git-cherry-pick.txt > +++ b/Documentation/git-cherry-pick.txt > @@ -131,8 +131,8 @@ effect to your index in a row. > even without this option. Note also, that use of this option only > keeps commits that were initially empty (i.e. the commit recorded the > same tree as its parent). Commits which are made empty due to a > - previous commit are dropped. To force the inclusion of those commits > - use `--keep-redundant-commits`. > + previous commit will cause the cherry-pick to fail. To force the > + inclusion of those commits, use `--keep-redundant-commits`. > > --allow-empty-message:: > By default, cherry-picking a commit with an empty message will fail. > @@ -144,7 +144,11 @@ effect to your index in a row. > current history, it will become empty. By default these > redundant commits cause `cherry-pick` to stop so the user can > examine the commit. This option overrides that behavior and > - creates an empty commit object. Implies `--allow-empty`. > + creates an empty commit object. Note that use of this option only > + results in an empty commit when the commit was not initially empty, > + but rather became empty due to a previous commit. Commits that were > + initially empty will cause the cherry-pick to fail. To force the > + inclusion of those commits use `--allow-empty`. > > --strategy=:: > Use the given merge strategy. Should only be used once. > diff --git a/builtin/revert.c b/builtin/revert.c > index 89821bab95..d83977e36e 100644 > --- a/builtin/revert.c > +++ b/builtin/revert.c > @@ -134,10 +134,6 @@ static int run_sequencer(int argc, const char **argv, const char *prefix, > prepare_repo_settings(the_repository); > the_repository->settings.command_requires_full_index = 0; > > - /* implies allow_empty */ > - if (opts->keep_redundant_commits) > - opts->allow_empty = 1; > - > if (cleanup_arg) { > opts->default_msg_cleanup = get_cleanup_mode(cleanup_arg, 1); > opts->explicit_cleanup = 1; > diff --git a/t/t3505-cherry-pick-empty.sh b/t/t3505-cherry-pick-empty.sh > index eba3c38d5a..2709cfc677 100755 > --- a/t/t3505-cherry-pick-empty.sh > +++ b/t/t3505-cherry-pick-empty.sh > @@ -59,6 +59,12 @@ test_expect_success 'cherry pick an empty non-ff commit without --allow-empty' ' > test_must_fail git cherry-pick empty-change-branch > ' > > +test_expect_success 'cherry pick an empty non-ff commit with --keep-redundant-commits' ' > + git checkout main && > + test_must_fail git cherry-pick --keep-redundant-commits empty-change-branch 2>output && > + test_grep "The previous cherry-pick is now empty" output > +' > + > test_expect_success 'cherry pick an empty non-ff commit with --allow-empty' ' > git checkout main && > git cherry-pick --allow-empty empty-change-branch