Re: [PATCH 3/4] merge: apply autostash if fast-forward fails
From: Junio C Hamano <hidden>
Date: 2021-07-23 19:13:21
"Philippe Blain via GitGitGadget" [off-list ref] writes:
From: Philippe Blain <redacted> Since 'git merge' learned '--autostash' in a03b55530a (merge: teach --autostash option, 2020-04-07), 'cmd_merge', in the fast-forward case, calls 'create_autostash' before calling 'checkout_fast_forward' if '--autostash' is given. However, if 'checkout_fast_forward' fails, the autostash is not applied to the working tree, nor saved in the stash list, since the code simply calls 'goto done'. Be more helpful to the user by applying the autostash in that case. An easy way to test a failing fast-forward is when we are merging a branch that has a tracked file that conflicts with an untracked file in the working tree.
I think this one makes sense, as the case that is tested I know fast-forward (aka two-tree switching) would be atomic. If your working tree is already broken (e.g. triggers I/O errors in the middle, some directories having wrong permissions to make them unwritable by you, etc.), you would also see an error from fast-forward and you probably cannot tell these two cases apart, and trying to unstash the local changes may make things even worse, but I suspect that there isn't much you can do about it. Thanks.
quoted hunk
Signed-off-by: Philippe Blain <redacted> --- builtin/merge.c | 1 + t/t7600-merge.sh | 11 +++++++++++ 2 files changed, 12 insertions(+)diff --git a/builtin/merge.c b/builtin/merge.c index 74797b6c7a6..788a6b0cd55 100644 --- a/builtin/merge.c +++ b/builtin/merge.c@@ -1560,6 +1560,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix) &head_commit->object.oid, &commit->object.oid, overwrite_ignore)) { + apply_autostash(git_path_merge_autostash(the_repository)); ret = 1; goto done; }diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh index 1cbc9715a81..216113d3537 100755 --- a/t/t7600-merge.sh +++ b/t/t7600-merge.sh@@ -122,6 +122,8 @@ test_expect_success 'setup' ' c0=$(git rev-parse HEAD) && cp file.1 file && git add file && + cp file.1 other && + git add other && test_tick && git commit -m "commit 1" && git tag c1 &&@@ -711,6 +713,15 @@ test_expect_success 'fast-forward merge with --autostash' ' test_cmp result.1-5 file ' +test_expect_success 'failed fast-forward merge with --autostash' ' + git reset --hard c0 && + git merge-file file file.orig file.5 && + cp file.5 other && + test_must_fail git merge --autostash c1 2>err && + test_i18ngrep "Applied autostash." err && + test_cmp file.5 file +' + test_expect_success 'octopus merge with --autostash' ' git reset --hard c1 && git merge-file file file.orig file.3 &&