From: Phillip Wood Date: Tue, 28 Apr 2026 09:33:47 GMT Subject: Re: [PATCH v15 4/5] checkout: rollback lock on early returns in merge_working_tree Message-ID: <04b49202-d1bb-45a1-ae4d-4a87a5822ba1@gmail.com> In-Reply-To: Hi Harald On 24/04/2026 22:10, Harald Nordgren via GitGitGadget wrote: > From: Harald Nordgren > > merge_working_tree() acquires the index lock via > repo_hold_locked_index() but several early return paths exit > without calling rollback_lock_file(), leaving the lock held. > While this is currently harmless because the process exits soon > after, it becomes a problem if the function is ever called more > than once in the same process. > > Add rollback_lock_file() calls to all early return paths. Thanks for splitting this out, it looks good Phillip > > Signed-off-by: Harald Nordgren > --- > builtin/checkout.c | 29 ++++++++++++++++++++++------- > 1 file changed, 22 insertions(+), 7 deletions(-) > > diff --git a/builtin/checkout.c b/builtin/checkout.c > index e031e61886..c80c62b37b 100644 > --- a/builtin/checkout.c > +++ b/builtin/checkout.c > @@ -783,8 +783,10 @@ static int merge_working_tree(const struct checkout_opts *opts, > struct tree *new_tree; > > repo_hold_locked_index(the_repository, &lock_file, LOCK_DIE_ON_ERROR); > - if (repo_read_index_preload(the_repository, NULL, 0) < 0) > + if (repo_read_index_preload(the_repository, NULL, 0) < 0) { > + rollback_lock_file(&lock_file); > return error(_("index file corrupt")); > + } > > resolve_undo_clear_index(the_repository->index); > if (opts->new_orphan_branch && opts->orphan_from_empty_tree) { > @@ -797,14 +799,18 @@ static int merge_working_tree(const struct checkout_opts *opts, > } else { > new_tree = repo_get_commit_tree(the_repository, > new_branch_info->commit); > - if (!new_tree) > + if (!new_tree) { > + rollback_lock_file(&lock_file); > return error(_("unable to read tree (%s)"), > oid_to_hex(&new_branch_info->commit->object.oid)); > + } > } > if (opts->discard_changes) { > ret = reset_tree(new_tree, opts, 1, writeout_error, new_branch_info); > - if (ret) > + if (ret) { > + rollback_lock_file(&lock_file); > return ret; > + } > } else { > struct tree_desc trees[2]; > struct tree *tree; > @@ -814,6 +820,7 @@ static int merge_working_tree(const struct checkout_opts *opts, > refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL, NULL); > > if (unmerged_index(the_repository->index)) { > + rollback_lock_file(&lock_file); > error(_("you need to resolve your current index first")); > return 1; > } > @@ -857,15 +864,19 @@ static int merge_working_tree(const struct checkout_opts *opts, > struct strbuf sb = STRBUF_INIT; > struct strbuf old_commit_shortname = STRBUF_INIT; > > - if (!opts->merge) > + if (!opts->merge) { > + rollback_lock_file(&lock_file); > return 1; > + } > > /* > * Without old_branch_info->commit, the below is the same as > * the two-tree unpack we already tried and failed. > */ > - if (!old_branch_info->commit) > + if (!old_branch_info->commit) { > + rollback_lock_file(&lock_file); > return 1; > + } > old_tree = repo_get_commit_tree(the_repository, > old_branch_info->commit); > > @@ -897,8 +908,10 @@ static int merge_working_tree(const struct checkout_opts *opts, > ret = reset_tree(new_tree, > opts, 1, > writeout_error, new_branch_info); > - if (ret) > + if (ret) { > + rollback_lock_file(&lock_file); > return ret; > + } > o.ancestor = old_branch_info->name; > if (!old_branch_info->name) { > strbuf_add_unique_abbrev(&old_commit_shortname, > @@ -920,8 +933,10 @@ static int merge_working_tree(const struct checkout_opts *opts, > writeout_error, new_branch_info); > strbuf_release(&o.obuf); > strbuf_release(&old_commit_shortname); > - if (ret) > + if (ret) { > + rollback_lock_file(&lock_file); > return ret; > + } > } > } >