From a9865116582860d7d5191af2dcca9e6d742008c4 Mon Sep 17 00:00:00 2001 From: tsukasa inoue Date: Wed, 21 Oct 2026 23:03:40 +0900 Subject: [PATCH 1/2] branch: return an error from setup_tracking() setup_tracking() calls exit(1) when it cannot write the tracking configuration. This exit was introduced in 27852b2c53 (branch: report errors in tracking branch setup, 2016-02-22). Because of it, callers cannot continue after a tracking failure, even though the ref has already been created. Change setup_tracking() to return an error instead of exiting, and make create_branch() and dwim_and_setup_tracking() return that value too. This does not change behavior. Callers still exit with status 1 on failure, as before. Changing checkout Signed-off-by: tsukasa inoue --- branch.c | 35 +++++++++++++++++++++-------------- branch.h | 21 +++++++++++++-------- builtin/branch.c | 17 ++++++++++++----- builtin/checkout.c | 17 +++++++++-------- 4 files changed, 55 insertions(+), 35 deletions(-) diff --git a/branch.c b/branch.c index 22f4f46b96ed3a..27be5ecc3ed9bb 100644 --- a/branch.c +++ b/branch.c @@ -249,12 +249,13 @@ static int inherit_tracking(struct tracking *tracking, const char *orig_ref) * will not be expanded to "refs/remotes/origin/main", so it is not safe * for 'orig_ref' to be raw user input. */ -static void setup_tracking(const char *new_ref, const char *orig_ref, - enum branch_track track, int quiet) +static int setup_tracking(const char *new_ref, const char *orig_ref, + enum branch_track track, int quiet) { struct tracking tracking; struct string_list tracking_srcs = STRING_LIST_INIT_DUP; int config_flags = quiet ? 0 : BRANCH_CONFIG_VERBOSE; + int ret = 0; struct find_tracked_branch_cb ftb_cb = { .tracking = &tracking, .ambiguous_remotes = STRING_LIST_INIT_DUP, @@ -343,11 +344,12 @@ static void setup_tracking(const char *new_ref, const char *orig_ref, string_list_append(tracking.srcs, orig_ref); if (install_branch_config_multiple_remotes(config_flags, new_ref, tracking.remote, tracking.srcs) < 0) - exit(1); + ret = -1; cleanup: string_list_clear(&tracking_srcs, 0); string_list_clear(&ftb_cb.ambiguous_remotes, 0); + return ret; } int read_branch_desc(struct strbuf *buf, const char *branch_name) @@ -627,10 +629,10 @@ static void dwim_branch_start(struct repository *r, const char *start_name, FREE_AND_NULL(real_ref); } -void create_branch(struct repository *r, - const char *name, const char *start_name, - int force, int clobber_head_ok, int reflog, - int quiet, enum branch_track track, int dry_run) +int create_branch(struct repository *r, + const char *name, const char *start_name, + int force, int clobber_head_ok, int reflog, + int quiet, enum branch_track track, int dry_run) { struct object_id oid; char *real_ref; @@ -639,6 +641,7 @@ void create_branch(struct repository *r, struct ref_transaction *transaction; struct strbuf err = STRBUF_INIT; int flags = 0; + int ret = 0; char *msg; if (track == BRANCH_TRACK_OVERRIDE) @@ -676,21 +679,25 @@ void create_branch(struct repository *r, free(msg); if (real_ref && track) - setup_tracking(ref.buf + 11, real_ref, track, quiet); + ret = setup_tracking(ref.buf + 11, real_ref, track, quiet); cleanup: strbuf_release(&ref); free(real_ref); + return ret; } -void dwim_and_setup_tracking(struct repository *r, const char *new_ref, - const char *orig_ref, enum branch_track track, - int quiet) +int dwim_and_setup_tracking(struct repository *r, const char *new_ref, + const char *orig_ref, enum branch_track track, + int quiet) { char *real_orig_ref = NULL; + int ret; + dwim_branch_start(r, orig_ref, track, &real_orig_ref, NULL); - setup_tracking(new_ref, real_orig_ref, track, quiet); + ret = setup_tracking(new_ref, real_orig_ref, track, quiet); free(real_orig_ref); + return ret; } /** @@ -840,8 +847,8 @@ void create_branches_recursively(struct repository *r, const char *name, * tedious to determine whether or not tracking was set up in the * superproject. */ - if (track) - setup_tracking(name, tracking_name, track, quiet); + if (track && setup_tracking(name, tracking_name, track, quiet)) + exit(1); for (i = 0; i < submodule_entry_list.entry_nr; i++) { if (submodule_create_branch( diff --git a/branch.h b/branch.h index e9b1f7b37df06f..4bc4527284e23b 100644 --- a/branch.h +++ b/branch.h @@ -34,10 +34,13 @@ enum branch_track { * causes new_ref to track whatever orig_ref tracks. * * - quiet suppresses tracking information. + * + * Returns 0 on success, or -1 if the tracking configuration could not be + * written. */ -void dwim_and_setup_tracking(struct repository *r, const char *new_ref, - const char *orig_ref, enum branch_track track, - int quiet); +int dwim_and_setup_tracking(struct repository *r, const char *new_ref, + const char *orig_ref, enum branch_track track, + int quiet); /* * Creates a new branch, where: @@ -63,12 +66,14 @@ void dwim_and_setup_tracking(struct repository *r, const char *new_ref, * * - dry_run causes the branch to be validated but not created. * + * Returns 0 on success, or -1 if the tracking configuration could not be + * written. */ -void create_branch(struct repository *r, - const char *name, const char *start_name, - int force, int clobber_head_ok, - int reflog, int quiet, enum branch_track track, - int dry_run); +int create_branch(struct repository *r, + const char *name, const char *start_name, + int force, int clobber_head_ok, + int reflog, int quiet, enum branch_track track, + int dry_run); /* * Creates a new branch in a repository and its submodules (and its diff --git a/builtin/branch.c b/builtin/branch.c index a613148fc72786..b536b619bb03ca 100644 --- a/builtin/branch.c +++ b/builtin/branch.c @@ -1253,9 +1253,13 @@ int cmd_branch(int argc, die(_("branch '%s' does not exist"), branch->name); } - dwim_and_setup_tracking(the_repository, branch->name, - new_upstream, BRANCH_TRACK_OVERRIDE, - quiet); + if (dwim_and_setup_tracking(the_repository, branch->name, + new_upstream, BRANCH_TRACK_OVERRIDE, + quiet)) { + strbuf_release(&buf); + ret = 1; + goto out; + } strbuf_release(&buf); } else if (unset_upstream) { struct branch *branch; @@ -1305,8 +1309,11 @@ int cmd_branch(int argc, ret = 0; goto out; } - create_branch(the_repository, branch_name, start_name, force, 0, - reflog, quiet, track, 0); + if (create_branch(the_repository, branch_name, start_name, + force, 0, reflog, quiet, track, 0)) { + ret = 1; + goto out; + } } else usage_with_options(builtin_branch_usage, options); diff --git a/builtin/checkout.c b/builtin/checkout.c index 2d575a4f57f76e..13a2938b4258c8 100644 --- a/builtin/checkout.c +++ b/builtin/checkout.c @@ -979,14 +979,15 @@ static void update_refs_for_switch(const struct checkout_opts *opts, free(refname); } else - create_branch(the_repository, - opts->new_branch, new_branch_info->name, - opts->new_branch_force ? 1 : 0, - opts->new_branch_force ? 1 : 0, - opts->new_branch_log, - opts->quiet, - opts->track, - 0); + if (create_branch(the_repository, + opts->new_branch, new_branch_info->name, + opts->new_branch_force ? 1 : 0, + opts->new_branch_force ? 1 : 0, + opts->new_branch_log, + opts->quiet, + opts->track, + 0)) + exit(1); free(new_branch_info->name); free(new_branch_info->refname); new_branch_info->name = xstrdup(opts->new_branch); From fcc73a773a7eba2612d983f8957b82f3d4fc09ef Mon Sep 17 00:00:00 2001 From: tsukasa inoue Date: Wed, 21 Oct 2026 23:16:11 +0900 Subject: [PATCH 2/2] checkout: finish switching when the tracking config cannot be written When git switch -c / (or checkout -b) cannot write the tracking config, for example because .git/config.lock exists, the worktree, the index and the new branch ref have already been updated. Git then exits with status 1 while HEAD still points to the original branch. The changes of the switch remain staged, and the post-checkout hook does not run. create_branch() now returns an error instead of exiting. Make checkout ignore that error so that the switch completes and the command exits with status 0. The error and the hint are still printed. Match push -u, clone and fetch, which also print the error and continue. The upstream can be set later with the command shown in the hint. Keep git branch failing when the tracking config cannot be written, so its behavior does not change; t3200 covers this. Making the switch fully atomic, undoing the worktree, the index, the ref and the config when the tracking config fails, is a separate topic. Signed-off-by: tsukasa inoue --- builtin/checkout.c | 23 ++++++++++++++--------- t/t2027-checkout-track.sh | 20 ++++++++++++++++++++ t/t2060-switch.sh | 20 ++++++++++++++++++++ t/t3200-branch.sh | 13 +++++++++++++ 4 files changed, 67 insertions(+), 9 deletions(-) diff --git a/builtin/checkout.c b/builtin/checkout.c index 13a2938b4258c8..c5e2202026ef80 100644 --- a/builtin/checkout.c +++ b/builtin/checkout.c @@ -979,15 +979,20 @@ static void update_refs_for_switch(const struct checkout_opts *opts, free(refname); } else - if (create_branch(the_repository, - opts->new_branch, new_branch_info->name, - opts->new_branch_force ? 1 : 0, - opts->new_branch_force ? 1 : 0, - opts->new_branch_log, - opts->quiet, - opts->track, - 0)) - exit(1); + /* + * Not fatal: the error and hint have already been + * shown, and like "push -u" and "clone" we finish + * the switch instead of leaving HEAD on the old + * branch with the worktree already updated. + */ + create_branch(the_repository, + opts->new_branch, new_branch_info->name, + opts->new_branch_force ? 1 : 0, + opts->new_branch_force ? 1 : 0, + opts->new_branch_log, + opts->quiet, + opts->track, + 0); free(new_branch_info->name); free(new_branch_info->refname); new_branch_info->name = xstrdup(opts->new_branch); diff --git a/t/t2027-checkout-track.sh b/t/t2027-checkout-track.sh index c01f1cd617c72b..c3be183bfcc411 100755 --- a/t/t2027-checkout-track.sh +++ b/t/t2027-checkout-track.sh @@ -47,6 +47,26 @@ test_expect_success 'checkout --track -b overrides autoSetupMerge=inherit' ' test_cmp_config refs/heads/main branch.b4.merge ' +test_expect_success 'checkout -b completes when tracking config cannot be written' ' + test_when_finished "git update-ref -d refs/remotes/lockremote/lockbranch" && + test_when_finished "git branch -D lock-new" && + test_when_finished "git checkout main" && + test_config remote.lockremote.url . && + test_config remote.lockremote.fetch "+refs/heads/*:refs/remotes/lockremote/*" && + git update-ref refs/remotes/lockremote/lockbranch one && + test_when_finished "rm -f .git/config.lock" && + >.git/config.lock && + git -c core.configLockTimeout=0 \ + checkout -b lock-new lockremote/lockbranch 2>err && + test_grep "unable to write upstream branch configuration" err && + echo refs/heads/lock-new >expect && + git symbolic-ref HEAD >actual && + test_cmp expect actual && + git diff --cached --exit-code && + rm -f .git/config.lock && + test_must_fail git config branch.lock-new.remote +' + test_expect_success 'ambiguous tracking info' ' # Set up a few remote repositories git init --bare --initial-branch=trunk src1 && diff --git a/t/t2060-switch.sh b/t/t2060-switch.sh index cec2fe6876c2fe..b4f137acc3b6fe 100755 --- a/t/t2060-switch.sh +++ b/t/t2060-switch.sh @@ -146,6 +146,26 @@ test_expect_success 'tracking info copied with autoSetupMerge=inherit' ' test_cmp_config "" --default "" branch.main2.merge ' +test_expect_success 'switch -c completes when tracking config cannot be written' ' + test_when_finished "git update-ref -d refs/remotes/lockremote/lockbranch" && + test_when_finished "git branch -D lock-new" && + test_when_finished "git switch main" && + test_config remote.lockremote.url . && + test_config remote.lockremote.fetch "+refs/heads/*:refs/remotes/lockremote/*" && + git update-ref refs/remotes/lockremote/lockbranch first-branch && + test_when_finished "rm -f .git/config.lock" && + >.git/config.lock && + git -c core.configLockTimeout=0 \ + switch -c lock-new lockremote/lockbranch 2>err && + test_grep "unable to write upstream branch configuration" err && + echo refs/heads/lock-new >expect && + git symbolic-ref HEAD >actual && + test_cmp expect actual && + git diff --cached --exit-code && + rm -f .git/config.lock && + test_must_fail git config branch.lock-new.remote +' + test_expect_success 'switch back when temporarily detached and checked out elsewhere ' ' test_when_finished " git worktree remove wt1 ||: diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh index cdb6c6a6342a0c..ca1a1c7f867eb3 100755 --- a/t/t3200-branch.sh +++ b/t/t3200-branch.sh @@ -1080,6 +1080,19 @@ test_expect_success '--set-upstream-to fails on locked config' ' test_grep "could not lock config file .git/config" err ' +test_expect_success 'branch with start point fails when tracking config cannot be written' ' + test_when_finished "git branch -D lock-new || :" && + test_when_finished "git update-ref -d refs/remotes/lockremote/lockbranch" && + test_config remote.lockremote.url . && + test_config remote.lockremote.fetch "+refs/heads/*:refs/remotes/lockremote/*" && + git update-ref refs/remotes/lockremote/lockbranch HEAD && + test_when_finished "rm -f .git/config.lock" && + >.git/config.lock && + test_must_fail git -c core.configLockTimeout=0 \ + branch lock-new lockremote/lockbranch 2>err && + test_grep "unable to write upstream branch configuration" err +' + test_expect_success 'use --set-upstream-to modify HEAD' ' test_config branch.main.remote foo && test_config branch.main.merge foo &&