diff: fix --merge-base with annotated tags

Checking early for OBJ_COMMIT excludes other objects that can be
resolved to commits, like annotated tags.  If we remove it, annotated
tags will be resolved and handled just fine by
lookup_commit_reference(), and if we are given something that can't be
resolved to a commit, we'll still get a useful error message, e.g.:

> error: object 21ab162211ac3ef13c37603ca88b27e9c7e0d40b is a tree, not a commit
> fatal: no merge base found

Signed-off-by: Alyssa Ross <hi@alyssa.is>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/diff-lib.c b/diff-lib.c
index 6b0c6a7180cc0432a7e919271dfad74405d30096..543398b4d86b3797c1d979eda9a57d32d7860c62 100644 (file)
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -572,8 +572,6 @@ void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb)
                struct object *obj = revs->pending.objects[i].item;
                if (obj->flags)
                        die(_("--merge-base does not work with ranges"));
-               if (obj->type != OBJ_COMMIT)
-                       die(_("--merge-base only works with commits"));
        }
 
        /*

diff --git a/t/t4068-diff-symmetric-merge-base.sh b/t/t4068-diff-symmetric-merge-base.sh
index 2d650d8f1032ca7c113fa0f48c72719fb08ab245..541642650f533816ae8ea6490141893cbc111ce4 100755 (executable)
--- a/t/t4068-diff-symmetric-merge-base.sh
+++ b/t/t4068-diff-symmetric-merge-base.sh
@@ -34,7 +34,7 @@ test_expect_success setup '
        echo c >c &&
        git add c &&
        git commit -m C &&
-       git tag commit-C &&
+       git tag -m commit-C commit-C &&
        git merge -m D main &&
        git tag commit-D &&
        git checkout main &&
@@ -109,6 +109,13 @@ do
                test_cmp expect actual
        '
 
+       test_expect_success "$cmd --merge-base with annotated tag" '
+               git checkout main &&
+               git $cmd commit-C >expect &&
+               git $cmd --merge-base commit-C >actual &&
+               test_cmp expect actual
+       '
+
        test_expect_success "$cmd --merge-base with one commit and unstaged changes" '
                git checkout main &&
                test_when_finished git reset --hard &&
@@ -143,7 +150,7 @@ do
        test_expect_success "$cmd --merge-base with non-commit" '
                git checkout main &&
                test_must_fail git $cmd --merge-base main^{tree} 2>err &&
-               test_i18ngrep "fatal: --merge-base only works with commits" err
+               test_i18ngrep "is a tree, not a commit" err
        '
 
        test_expect_success "$cmd --merge-base with no merge bases and one commit" '
@@ -169,7 +176,7 @@ do
 
        test_expect_success "$cmd --merge-base commit and non-commit" '
                test_must_fail git $cmd --merge-base br2 main^{tree} 2>err &&
-               test_i18ngrep "fatal: --merge-base only works with commits" err
+               test_i18ngrep "is a tree, not a commit" err
        '
 
        test_expect_success "$cmd --merge-base with no merge bases and two commits" '