branch: record creation of renamed branch in HEAD's log

Renaming the current branch adds an event to the current branch's log
and to HEAD's log.  However, the logged entries differ.  The entry in
the branch's log represents the entire renaming operation (the old and
new hash are identical), whereas the entry in HEAD's log represents
the deletion only (the new sha1 is null).

Extend replace_each_worktree_head_symref(), whose only caller is
branch_rename(), to take a reflog message argument.  This allows the
creation of the new ref to be recorded in HEAD's log.  As a result,
the renaming event is represented by two entries (a deletion and a
creation entry) in HEAD's log.

It's a bit unfortunate that the branch's log and HEAD's log now
represent the renaming event in different ways.  Given that the
renaming operation is not atomic, the two-entry form is a more
accurate representation of the operation and is more useful for
debugging purposes if a failure occurs between the deletion and
creation events.  It would make sense to move the branch's log to the
two-entry form, but this would involve changes to how the rename is
carried out and to how the update flags and reflogs are processed for
deletions, so it may not be worth the effort.

Based-on-patch-by: Jeff King <peff@peff.net>
Signed-off-by: Kyle Meyer <kyle@kyleam.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/branch.c b/branch.c
index b955d4f316c799f7788896806302bfd4dbcf3ec4..5c12036b0206fe250f50bea30578785b090f9ee4 100644 (file)
--- a/branch.c
+++ b/branch.c
@@ -345,7 +345,8 @@ void die_if_checked_out(const char *branch, int ignore_current_worktree)
            branch, wt->path);
 }
 
-int replace_each_worktree_head_symref(const char *oldref, const char *newref)
+int replace_each_worktree_head_symref(const char *oldref, const char *newref,
+                                     const char *logmsg)
 {
        int ret = 0;
        struct worktree **worktrees = get_worktrees(0);
@@ -358,7 +359,7 @@ int replace_each_worktree_head_symref(const char *oldref, const char *newref)
                        continue;
 
                if (set_worktree_head_symref(get_worktree_git_dir(worktrees[i]),
-                                            newref)) {
+                                            newref, logmsg)) {
                        ret = -1;
                        error(_("HEAD of working tree %s is not updated"),
                              worktrees[i]->path);

diff --git a/branch.h b/branch.h
index 3103eb9add31e08600f9fa158303417e36d3b229..b07788558c0e76a701b571f73c0462dcf2abcc63 100644 (file)
--- a/branch.h
+++ b/branch.h
@@ -71,6 +71,7 @@ extern void die_if_checked_out(const char *branch, int ignore_current_worktree);
  * This will be used when renaming a branch. Returns 0 if successful, non-zero
  * otherwise.
  */
-extern int replace_each_worktree_head_symref(const char *oldref, const char *newref);
+extern int replace_each_worktree_head_symref(const char *oldref, const char *newref,
+                                            const char *logmsg);
 
 #endif

diff --git a/builtin/branch.c b/builtin/branch.c
index 8f8242e07c8e109e58f203b88f5e40d57076ac4e..e1f97dcfc4ea9ebe0a7e1b47a51e056930daa032 100644 (file)
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -579,14 +579,15 @@ static void rename_branch(const char *oldname, const char *newname, int force)
 
        if (rename_ref(oldref.buf, newref.buf, logmsg.buf))
                die(_("Branch rename failed"));
-       strbuf_release(&logmsg);
 
        if (recovery)
                warning(_("Renamed a misnamed branch '%s' away"), oldref.buf + 11);
 
-       if (replace_each_worktree_head_symref(oldref.buf, newref.buf))
+       if (replace_each_worktree_head_symref(oldref.buf, newref.buf, logmsg.buf))
                die(_("Branch renamed to %s, but HEAD is not updated!"), newname);
 
+       strbuf_release(&logmsg);
+
        strbuf_addf(&oldsection, "branch.%s", oldref.buf + 11);
        strbuf_release(&oldref);
        strbuf_addf(&newsection, "branch.%s", newref.buf + 11);

diff --git a/refs.h b/refs.h
index 5880886a7c06f0f6a6f8617fbc8e5edae9977cb2..e529f4c3a88a79488df4b610b65a1c9d9c18c4a0 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -334,7 +334,8 @@ int create_symref(const char *refname, const char *target, const char *logmsg);
  * $GIT_DIR points to.
  * Return 0 if successful, non-zero otherwise.
  * */
-int set_worktree_head_symref(const char *gitdir, const char *target);
+int set_worktree_head_symref(const char *gitdir, const char *target,
+                            const char *logmsg);
 
 enum action_on_err {
        UPDATE_REFS_MSG_ON_ERR,

diff --git a/refs/files-backend.c b/refs/files-backend.c
index f6e7c192c59f03acbd179055b219f70b7a4ca8a9..42b137bb1c274c353b7206ae8652648bc6dc9b45 100644 (file)
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -3055,7 +3055,7 @@ static int files_create_symref(struct ref_store *ref_store,
        return ret;
 }
 
-int set_worktree_head_symref(const char *gitdir, const char *target)
+int set_worktree_head_symref(const char *gitdir, const char *target, const char *logmsg)
 {
        static struct lock_file head_lock;
        struct ref_lock *lock;
@@ -3083,7 +3083,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
        lock->lk = &head_lock;
        lock->ref_name = xstrdup(head_rel);
 
-       ret = create_symref_locked(lock, head_rel, target, NULL);
+       ret = create_symref_locked(lock, head_rel, target, logmsg);
 
        unlock_ref(lock); /* will free lock */
        strbuf_release(&head_path);

diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 47bc1512804ec24dcb9ea6a930900ca2202cdf38..e36ed3b4e18e22986233f72e016b491c801117db 100755 (executable)
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -139,9 +139,10 @@ test_expect_success 'git branch -M baz bam should succeed when baz is checked ou
        test $(git rev-parse --abbrev-ref HEAD) = bam
 '
 
-test_expect_success 'git branch -M baz bam should add entry to .git/logs/HEAD' '
+test_expect_success 'git branch -M baz bam should add entries to .git/logs/HEAD' '
        msg="Branch: renamed refs/heads/baz to refs/heads/bam" &&
-       grep " 0\{40\}.*$msg$" .git/logs/HEAD
+       grep " 0\{40\}.*$msg$" .git/logs/HEAD &&
+       grep "^0\{40\}.*$msg$" .git/logs/HEAD
 '
 
 test_expect_success 'git branch -M baz bam should succeed when baz is checked out as linked working tree' '