sequencer: unify label lookup

The arguments to the `reset` and `merge` commands may be a label created
with a `label` command or an arbitrary commit name. The `merge` command
uses the lookup_label() function to lookup its arguments but `reset` has
a slightly different version of that function in do_reset(). Reduce this
code duplication by calling lookup_label() from do_reset() as well.

This change improves the behavior of `reset` when the argument is a
tree.  Previously `reset` would accept a tree only for the rebase to
fail with

       update_ref failed for ref 'HEAD': cannot update ref 'HEAD': trying to write non-commit object da5497437fd67ca928333aab79c4b4b55036ea66 to branch 'HEAD'

Using lookup_label() means do_reset() will now error out straight away
if its argument is not a commit.

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 f0f1af4d4784b4ad7536a0a3de2857ab1dc8ca27..f2d0667b5714d86799ef11bb44a053b40eab3ec7 100644 (file)
--- a/sequencer.c
+++ b/sequencer.c
@@ -3694,6 +3694,26 @@ 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)
+{
+       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_reset(struct repository *r,
                    const char *name, int len,
                    struct replay_opts *opts)
@@ -3725,6 +3745,7 @@ 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 +3753,12 @@ 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(name, len, &ref_name);
+               if (!commit) {
+                       ret = -1;
                        goto cleanup;
                }
+               oid = commit->object.oid;
        }
 
        setup_unpack_trees_porcelain(&unpack_tree_opts, "reset");
@@ -3784,26 +3805,6 @@ 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,

diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
index f351701fec281aa6a88e9ee7185101639c8bbcd6..fbbc4439bfe608fc1fdcd2857874359a2b9651d6 100755 (executable)
--- a/t/t3430-rebase-merges.sh
+++ b/t/t3430-rebase-merges.sh
@@ -138,6 +138,14 @@ 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 'failed `merge -C` writes patch (may be rescheduled, too)' '
        test_when_finished "test_might_fail git rebase --abort" &&
        git checkout -b conflicting-merge A &&