Merge branch 'pw/strict-label-lookups'

Correct an error where `git rebase` would mistakenly use a branch or
tag named "refs/rewritten/xyz" when missing a rebase label.

* pw/strict-label-lookups:
  sequencer: tighten label lookups
  sequencer: unify label lookup

2 files changed, 45 insertions, 25 deletions

diff --git a/sequencer.c b/sequencer.c
index a46f3ad2e3..3ef77311cf 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -3694,6 +3694,28 @@ static const char *reflog_message(struct replay_opts *opts,
 	return buf.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);
+	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);
+	}
+
+	if (!commit)
+		error(_("could not resolve '%s'"), buf->buf);
+
+	return commit;
+}
+
 static int do_reset(struct repository *r,
 		    const char *name, int len,
 		    struct replay_opts *opts)
@@ -3725,6 +3747,7 @@ static int do_reset(struct repository *r,
 		oidcpy(&oid, &opts->squash_onto);
 	} else {
 		int i;
+		struct commit *commit;
 
 		/* Determine the length of the label */
 		for (i = 0; i < len; i++)
@@ -3732,12 +3755,12 @@ static int do_reset(struct repository *r,
 				break;
 		len = i;
 
-		strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
-		if (get_oid(ref_name.buf, &oid) &&
-		    get_oid(ref_name.buf + strlen("refs/rewritten/"), &oid)) {
-			ret = error(_("could not read '%s'"), ref_name.buf);
+		commit = lookup_label(r, name, len, &ref_name);
+		if (!commit) {
+			ret = -1;
 			goto cleanup;
 		}
+		oid = commit->object.oid;
 	}
 
 	setup_unpack_trees_porcelain(&unpack_tree_opts, "reset");
@@ -3785,26 +3808,6 @@ cleanup:
 	return ret;
 }
 
-static struct commit *lookup_label(const char *label, int len,
-				   struct strbuf *buf)
-{
-	struct commit *commit;
-
-	strbuf_reset(buf);
-	strbuf_addf(buf, "refs/rewritten/%.*s", len, label);
-	commit = lookup_commit_reference_by_name(buf->buf);
-	if (!commit) {
-		/* fall back to non-rewritten ref or commit */
-		strbuf_splice(buf, 0, strlen("refs/rewritten/"), "", 0);
-		commit = lookup_commit_reference_by_name(buf->buf);
-	}
-
-	if (!commit)
-		error(_("could not resolve '%s'"), buf->buf);
-
-	return commit;
-}
-
 static int do_merge(struct repository *r,
 		    struct commit *commit,
 		    const char *arg, int arg_len,
@@ -3852,7 +3855,7 @@ 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 f351701fec..fa2a06c19f 100755
--- a/t/t3430-rebase-merges.sh
+++ b/t/t3430-rebase-merges.sh
@@ -138,6 +138,23 @@ test_expect_success '`reset` refuses to overwrite untracked files' '
 	git rebase --abort
 '
 
+test_expect_success '`reset` rejects trees' '
+	test_when_finished "test_might_fail git rebase --abort" &&
+	test_must_fail env GIT_SEQUENCE_EDITOR="echo reset A^{tree} >" \
+		git rebase -i B C >out 2>err &&
+	grep "object .* is a tree" err &&
+	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 &&