From: Son Luong Ngoc via GitGitGadget Date: Wed, 03 Jun 2026 10:27:16 GMT Subject: [PATCH v2] rebase: skip branch symref aliases Message-ID: In-Reply-To: From: Son Luong Ngoc git rebase --update-refs can fail after the normal rebase path has updated the current branch when another local branch is a symref to it. This can happen during a default-branch rename where refs/heads/main points at refs/heads/master while users migrate. The sequencer queues update-ref commands from local branch decorations. Commit 106b6885c7 (rebase: ignore non-branch update-refs) filters out decorations that are not local branches, such as HEAD and tags. A branch symref is different: it is still a local branch decoration, but if it resolves to another branch then that target branch is itself present in the decoration list and will be updated as a concrete branch. Skip branch decorations whose symrefs resolve to refs/heads/*, because those targets are already represented by concrete branch decorations. This prevents aliases from scheduling a second update for the same branch. Keep symrefs to non-branch targets on the existing path. Preserve the existing checked-out branch handling before applying these skips. Such refs still need a todo-list comment instead of an update-ref command, even when the checked-out ref is the branch being rebased or a branch symref alias. Use a copy of the resolved HEAD ref so later ref resolution does not overwrite it. Signed-off-by: Son Luong Ngoc --- rebase: handle --update-refs branch symrefs Changes since v1: * Squashed the regression test and fix into a single patch. * Reworked the implementation per Phillip's review: skip local branch symrefs that are not checked out when their targets resolve to refs/heads/*, while preserving the existing behavior for symrefs to non-branch targets. * Preserved checked-out branch comments before applying the new symref skip, so worktrees still get the existing todo-list warning instead of an update-ref command. * Folded the symref coverage into the existing "--update-refs updates refs correctly" test, covering both an alias of HEAD and an alias of another branch. * Kept the relationship to 106b6885c7 in the commit message: non-local decorations are already filtered, and this patch handles the remaining local branch decorations that are symref aliases. Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2126%2Fsluongng%2Fsl%2Frebase-update-refs-symrefs-v2 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2126/sluongng/sl/rebase-update-refs-symrefs-v2 Pull-Request: https://github.com/gitgitgadget/git/pull/2126 Range-diff vs v1: 1: a550923440 < -: ---------- t3404: add failing branch symref test 2: 0ab0a71744 ! 1: 68f698225c rebase: skip branch symref aliases @@ Metadata ## Commit message ## rebase: skip branch symref aliases - rebase --update-refs records local branch decorations before replaying - commits. If a decoration is a symbolic branch such as refs/heads/main - pointing at refs/heads/master, updating it later dereferences back to - master and can fail because the normal rebase path already moved that - branch. + git rebase --update-refs can fail after the normal rebase path has + updated the current branch when another local branch is a symref to it. + This can happen during a default-branch rename where refs/heads/main + points at refs/heads/master while users migrate. - Resolve local branch symref decorations to their referents before - queuing update-ref commands, and skip duplicates. This keeps branch - aliases from scheduling a second update for the same underlying branch - while still using the existing old-OID check for the single queued - update. + The sequencer queues update-ref commands from local branch decorations. + Commit 106b6885c7 (rebase: ignore non-branch update-refs) filters out + decorations that are not local branches, such as HEAD and tags. A branch + symref is different: it is still a local branch decoration, but if it + resolves to another branch then that target branch is itself present in + the decoration list and will be updated as a concrete branch. + + Skip branch decorations whose symrefs resolve to refs/heads/*, because + those targets are already represented by concrete branch decorations. + This prevents aliases from scheduling a second update for the same + branch. Keep symrefs to non-branch targets on the existing path. + + Preserve the existing checked-out branch handling before applying these + skips. Such refs still need a todo-list comment instead of an update-ref + command, even when the checked-out ref is the branch being rebased or a + branch symref alias. Use a copy of the resolved HEAD ref so later ref + resolution does not overwrite it. Signed-off-by: Son Luong Ngoc @@ sequencer.c: static int add_decorations_to_list(const struct commit *commit, const struct name_decoration *decoration = get_name_decoration(&commit->object); - const char *head_ref = refs_resolve_ref_unsafe(get_main_ref_store(the_repository), - "HEAD", -+ struct ref_store *refs = get_main_ref_store(the_repository); -+ const char *head_ref = refs_resolve_ref_unsafe(refs, "HEAD", - RESOLVE_REF_READING, +- RESOLVE_REF_READING, - NULL, - NULL); -+ NULL, NULL); -+ char *resolved_head_ref = refs_resolve_refdup(refs, "HEAD", -+ RESOLVE_REF_READING, -+ NULL, NULL); -+ struct strbuf update_ref = STRBUF_INIT; ++ struct ref_store *refs = get_main_ref_store(the_repository); ++ char *head_ref = refs_resolve_refdup(refs, "HEAD", ++ RESOLVE_REF_READING, ++ NULL, NULL); while (decoration) { struct todo_item *item; const char *path; -+ const char *ref = decoration->name; + const char *resolved_ref; -+ int is_symref = 0; + int flags = 0; size_t base_offset = ctx->buf->len; /* -@@ sequencer.c: static int add_decorations_to_list(const struct commit *commit, - * updated by the default rebase behavior. - * Exclude it from the list of refs to update, - * as well as any non-branch decorations. -+ * -+ * Resolve branch symrefs after checking for the current HEAD so -+ * that aliases do not schedule duplicate updates for their -+ * referents. -+ * +- * If the branch is the current HEAD, then it will be +- * updated by the default rebase behavior. +- * Exclude it from the list of refs to update, +- * as well as any non-branch decorations. * Non-branch decorations may be present if the pretty format * includes "%d", which would have loaded all refs * into the global decoration table. @@ sequencer.c: static int add_decorations_to_list(const struct commit *commit, + continue; + } + -+ if (head_ref && !strcmp(head_ref, ref)) { ++ path = branch_checked_out(decoration->name); ++ ++ /* ++ * If the branch is the current HEAD, then it will be ++ * updated by the default rebase behavior. Exclude it from ++ * the list of refs to update, unless it is checked out and ++ * needs a comment in the todo list. ++ */ ++ if (!path && head_ref && !strcmp(head_ref, decoration->name)) { + decoration = decoration->next; + continue; + } + -+ strbuf_reset(&update_ref); -+ resolved_ref = refs_resolve_ref_unsafe(refs, ref, -+ RESOLVE_REF_READING | -+ RESOLVE_REF_NO_RECURSE, ++ resolved_ref = refs_resolve_ref_unsafe(refs, decoration->name, ++ RESOLVE_REF_READING, + NULL, &flags); -+ if ((flags & REF_ISSYMREF) && resolved_ref) { -+ if (!starts_with(resolved_ref, "refs/heads/")) { -+ decoration = decoration->next; -+ continue; -+ } -+ -+ strbuf_addstr(&update_ref, resolved_ref); -+ ref = update_ref.buf; -+ is_symref = 1; -+ } -+ -+ if ((is_symref && resolved_head_ref && -+ !strcmp(resolved_head_ref, ref)) || -+ string_list_has_string(&ctx->refs_to_oids, ref)) { ++ if (!path && resolved_ref && (flags & REF_ISSYMREF) && ++ starts_with(resolved_ref, "refs/heads/")) { decoration = decoration->next; continue; } @@ sequencer.c: static int add_decorations_to_list(const struct commit *commit, /* If the branch is checked out, then leave a comment instead. */ - if ((path = branch_checked_out(decoration->name))) { -+ if ((path = branch_checked_out(ref))) { ++ if (path) { item->command = TODO_COMMENT; strbuf_commented_addf(ctx->buf, comment_line_str, "Ref %s checked out at '%s'\n", -- decoration->name, path); -+ ref, path); - } else { - struct string_list_item *sti; - item->command = TODO_UPDATE_REF; -- strbuf_addf(ctx->buf, "%s\n", decoration->name); -+ strbuf_addf(ctx->buf, "%s\n", ref); - - sti = string_list_insert(&ctx->refs_to_oids, -- decoration->name); -- sti->util = init_update_ref_record(decoration->name); -+ ref); -+ sti->util = init_update_ref_record(ref); - } - - item->offset_in_buf = base_offset; @@ sequencer.c: static int add_decorations_to_list(const struct commit *commit, decoration = decoration->next; } -+ strbuf_release(&update_ref); -+ free(resolved_head_ref); ++ free(head_ref); return 0; } ## t/t3404-rebase-interactive.sh ## @@ t/t3404-rebase-interactive.sh: test_expect_success '--update-refs ignores non-branch decorations' ' - test_cmp expect actual ' --test_expect_failure '--update-refs skips branch symrefs to current branch' ' -+test_expect_success '--update-refs skips branch symrefs to current branch' ' - test_when_finished " - test_might_fail git rebase --abort && - git checkout primary && + test_expect_success '--update-refs updates refs correctly' ' ++ test_when_finished " ++ test_might_fail git symbolic-ref -d refs/heads/no-conflict-branch-alias && ++ test_might_fail git symbolic-ref -d refs/heads/second-alias ++ " && + git checkout -B update-refs no-conflict-branch && + git branch -f base HEAD~4 && + git branch -f first HEAD~3 && + git branch -f second HEAD~3 && + git branch -f third HEAD~1 && ++ git symbolic-ref refs/heads/no-conflict-branch-alias \ ++ refs/heads/no-conflict-branch && ++ git symbolic-ref refs/heads/second-alias refs/heads/second && + test_commit extra2 fileX && + git commit --amend --fixup=L && + +@@ t/t3404-rebase-interactive.sh: test_expect_success '--update-refs updates refs correctly' ' + + test_cmp_rev HEAD~3 refs/heads/first && + test_cmp_rev HEAD~3 refs/heads/second && ++ test_cmp_rev HEAD~3 refs/heads/second-alias && + test_cmp_rev HEAD~1 refs/heads/third && + test_cmp_rev HEAD refs/heads/no-conflict-branch && ++ test_cmp_rev HEAD refs/heads/no-conflict-branch-alias && ++ test_write_lines refs/heads/no-conflict-branch >expect && ++ git symbolic-ref refs/heads/no-conflict-branch-alias >actual && ++ test_cmp expect actual && ++ test_write_lines refs/heads/second >expect && ++ git symbolic-ref refs/heads/second-alias >actual && ++ test_cmp expect actual && + + q_to_tab >expect <<-\EOF && + Successfully rebased and updated refs/heads/update-refs. sequencer.c | 43 +++++++++++++++++++++++++---------- t/t3404-rebase-interactive.sh | 15 ++++++++++++ 2 files changed, 46 insertions(+), 12 deletions(-) diff --git a/sequencer.c b/sequencer.c index 1ee4b2875b..6ab8b47108 100644 --- a/sequencer.c +++ b/sequencer.c @@ -6445,28 +6445,46 @@ static int add_decorations_to_list(const struct commit *commit, struct todo_add_branch_context *ctx) { const struct name_decoration *decoration = get_name_decoration(&commit->object); - const char *head_ref = refs_resolve_ref_unsafe(get_main_ref_store(the_repository), - "HEAD", - RESOLVE_REF_READING, - NULL, - NULL); + struct ref_store *refs = get_main_ref_store(the_repository); + char *head_ref = refs_resolve_refdup(refs, "HEAD", + RESOLVE_REF_READING, + NULL, NULL); while (decoration) { struct todo_item *item; const char *path; + const char *resolved_ref; + int flags = 0; size_t base_offset = ctx->buf->len; /* - * If the branch is the current HEAD, then it will be - * updated by the default rebase behavior. - * Exclude it from the list of refs to update, - * as well as any non-branch decorations. * Non-branch decorations may be present if the pretty format * includes "%d", which would have loaded all refs * into the global decoration table. */ - if ((head_ref && !strcmp(head_ref, decoration->name)) || - (decoration->type != DECORATION_REF_LOCAL)) { + if (decoration->type != DECORATION_REF_LOCAL) { + decoration = decoration->next; + continue; + } + + path = branch_checked_out(decoration->name); + + /* + * If the branch is the current HEAD, then it will be + * updated by the default rebase behavior. Exclude it from + * the list of refs to update, unless it is checked out and + * needs a comment in the todo list. + */ + if (!path && head_ref && !strcmp(head_ref, decoration->name)) { + decoration = decoration->next; + continue; + } + + resolved_ref = refs_resolve_ref_unsafe(refs, decoration->name, + RESOLVE_REF_READING, + NULL, &flags); + if (!path && resolved_ref && (flags & REF_ISSYMREF) && + starts_with(resolved_ref, "refs/heads/")) { decoration = decoration->next; continue; } @@ -6478,7 +6496,7 @@ static int add_decorations_to_list(const struct commit *commit, memset(item, 0, sizeof(*item)); /* If the branch is checked out, then leave a comment instead. */ - if ((path = branch_checked_out(decoration->name))) { + if (path) { item->command = TODO_COMMENT; strbuf_commented_addf(ctx->buf, comment_line_str, "Ref %s checked out at '%s'\n", @@ -6501,6 +6519,7 @@ static int add_decorations_to_list(const struct commit *commit, decoration = decoration->next; } + free(head_ref); return 0; } diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh index 58b3bb0c27..bc0b6a31f7 100755 --- a/t/t3404-rebase-interactive.sh +++ b/t/t3404-rebase-interactive.sh @@ -1979,11 +1979,18 @@ test_expect_success '--update-refs ignores non-branch decorations' ' ' test_expect_success '--update-refs updates refs correctly' ' + test_when_finished " + test_might_fail git symbolic-ref -d refs/heads/no-conflict-branch-alias && + test_might_fail git symbolic-ref -d refs/heads/second-alias + " && git checkout -B update-refs no-conflict-branch && git branch -f base HEAD~4 && git branch -f first HEAD~3 && git branch -f second HEAD~3 && git branch -f third HEAD~1 && + git symbolic-ref refs/heads/no-conflict-branch-alias \ + refs/heads/no-conflict-branch && + git symbolic-ref refs/heads/second-alias refs/heads/second && test_commit extra2 fileX && git commit --amend --fixup=L && @@ -1991,8 +1998,16 @@ test_expect_success '--update-refs updates refs correctly' ' test_cmp_rev HEAD~3 refs/heads/first && test_cmp_rev HEAD~3 refs/heads/second && + test_cmp_rev HEAD~3 refs/heads/second-alias && test_cmp_rev HEAD~1 refs/heads/third && test_cmp_rev HEAD refs/heads/no-conflict-branch && + test_cmp_rev HEAD refs/heads/no-conflict-branch-alias && + test_write_lines refs/heads/no-conflict-branch >expect && + git symbolic-ref refs/heads/no-conflict-branch-alias >actual && + test_cmp expect actual && + test_write_lines refs/heads/second >expect && + git symbolic-ref refs/heads/second-alias >actual && + test_cmp expect actual && q_to_tab >expect <<-\EOF && Successfully rebased and updated refs/heads/update-refs. base-commit: c69baaf57ba26cf117c2b6793802877f19738b0d -- gitgitgadget