sequencer: tighten label lookups

The `label` command creates a ref refs/rewritten/<label> that the
`reset` and `merge` commands resolve by calling lookup_label(). That
uses lookup_commit_reference_by_name() to look up the label ref. As
lookup_commit_reference_by_name() uses the dwim rules when looking up
the label it will look for a branch named
refs/heads/refs/rewritten/<label> and return that instead of an error if
the branch exists and the label does not. Fix this by using read_ref()
followed by lookup_commit_object() when looking up labels.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Taylor Blau <me@ttaylorr.com>

diff --git a/sequencer.c b/sequencer.c
index f2d0667b5714d86799ef11bb44a053b40eab3ec7..7eec231234be11aa9f70d0b9add10ca0e27f5eb1 100644 (file)
--- a/sequencer.c
+++ b/sequencer.c
@@ -3694,15 +3694,17 @@ static const char *reflog_message(struct replay_opts *opts,
        return buf.buf;
 }
 
-static struct commit *lookup_label(const char *label, int len,
-                                  struct strbuf *buf)
+static struct commit *lookup_label(struct repository *r, const char *label,
+                                  int len, struct strbuf *buf)
 {
        struct commit *commit;
+       struct object_id oid;
 
        strbuf_reset(buf);
        strbuf_addf(buf, "refs/rewritten/%.*s", len, label);
-       commit = lookup_commit_reference_by_name(buf->buf);
-       if (!commit) {
+       if (!read_ref(buf->buf, &oid)) {
+               commit = lookup_commit_object(r, &oid);
+       } else {
                /* fall back to non-rewritten ref or commit */
                strbuf_splice(buf, 0, strlen("refs/rewritten/"), "", 0);
                commit = lookup_commit_reference_by_name(buf->buf);
@@ -3753,7 +3755,7 @@ static int do_reset(struct repository *r,
                                break;
                len = i;
 
-               commit = lookup_label(name, len, &ref_name);
+               commit = lookup_label(r, name, len, &ref_name);
                if (!commit) {
                        ret = -1;
                        goto cleanup;
@@ -3852,7 +3854,7 @@ static int do_merge(struct repository *r,
                k = strcspn(p, " \t\n");
                if (!k)
                        continue;
-               merge_commit = lookup_label(p, k, &ref_name);
+               merge_commit = lookup_label(r, p, k, &ref_name);
                if (!merge_commit) {
                        ret = error(_("unable to parse '%.*s'"), k, p);
                        goto leave_merge;

diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
index fbbc4439bfe608fc1fdcd2857874359a2b9651d6..fa2a06c19f0ff9890733817d066778c7634ab523 100755 (executable)
--- a/t/t3430-rebase-merges.sh
+++ b/t/t3430-rebase-merges.sh
@@ -146,6 +146,15 @@ test_expect_success '`reset` rejects trees' '
        test_must_be_empty out
 '
 
+test_expect_success '`reset` only looks for labels under refs/rewritten/' '
+       test_when_finished "test_might_fail git rebase --abort" &&
+       git branch refs/rewritten/my-label A &&
+       test_must_fail env GIT_SEQUENCE_EDITOR="echo reset my-label >" \
+               git rebase -i B C >out 2>err &&
+       grep "could not resolve ${SQ}my-label${SQ}" err &&
+       test_must_be_empty out
+'
+
 test_expect_success 'failed `merge -C` writes patch (may be rescheduled, too)' '
        test_when_finished "test_might_fail git rebase --abort" &&
        git checkout -b conflicting-merge A &&