gitproto: drop peeled "^{}" refs from AdvRefsToSlice

internal/gitproto/refs.go

@@ -87,12 +87,25 @@ func AdvertisedRefsV1(ctx context.Context, conn *Conn, service string) (*packp.A
 }
 
 // AdvRefsToSlice converts an AdvRefs to a slice of references.
+//
+// Peeled tag entries (names ending in "^{}") are dropped: they are
+// wire-protocol metadata exposing the commit a tag points to, not real refs.
+// Including them in target ref maps causes the planner to schedule a delete
+// for a non-existent ref, which receive-pack rejects with HTTP 400
+// "invalid reference name".
 func AdvRefsToSlice(ar *packp.AdvRefs) ([]*plumbing.Reference, error) {
 	refs, err := ar.ResolvedReferences()
 	if err != nil {
 		return nil, fmt.Errorf("resolved references: %w", err)
 	}
-	return refs, nil
+	out := refs[:0]
+	for _, ref := range refs {
+		if ref.Name().IsPeeled() {
+			continue
+		}
+		out = append(out, ref)
+	}
+	return out, nil
 }
 
 // AdvRefsCaps returns the sorted capability list from an AdvRefs.

internal/gitproto/refs_test.go

@@ -130,6 +130,31 @@ func TestAdvRefsToSlice(t *testing.T) {
 	}
 }
 
+// Regression: v1 advertisements include peeled "^{}" entries for annotated tags
+// to expose the commit the tag points at. They are wire-protocol metadata, not
+// real refs — receive-pack rejects them with "invalid reference name" when the
+// planner schedules a delete for one. AdvRefsToSlice must drop them.
+func TestAdvRefsToSliceDropsPeeledTagEntries(t *testing.T) {
+	adv := &packp.AdvRefs{}
+	tagHash := plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
+	commitHash := plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb")
+	adv.References = []*plumbing.Reference{
+		plumbing.NewHashReference("refs/tags/v1", tagHash),
+		plumbing.NewHashReference("refs/tags/v1^{}", commitHash),
+	}
+
+	refs, err := AdvRefsToSlice(adv)
+	if err != nil {
+		t.Fatalf("AdvRefsToSlice: %v", err)
+	}
+	if len(refs) != 1 {
+		t.Fatalf("expected 1 ref after peeled drop, got %d: %v", len(refs), refs)
+	}
+	if refs[0].Name() != "refs/tags/v1" {
+		t.Errorf("got %s, want refs/tags/v1", refs[0].Name())
+	}
+}
+
 func TestDecodeV1AdvRefs(t *testing.T) {
 	// Empty data should return ErrEmptyRemoteRepository.
 	_, err := decodeV1AdvRefs(nil)