1 files changed, 45 insertions, 0 deletions
diff --git a/commitquery/query_merge_bases.go b/commitquery/query_merge_bases.go
new file mode 100644
index 00000000..384ee019
--- /dev/null
+++ b/commitquery/query_merge_bases.go
@@ -0,0 +1,45 @@
+package commitquery
+
+import (
+	"slices"
+
+	objectid "codeberg.org/lindenii/furgit/object/id"
+)
+
+// MergeBases reports all merge bases in Git's merge-base --all order.
+//
+// Both inputs are peeled through annotated tags before commit traversal.
+func (query *query) MergeBases(left, right objectid.ObjectID) ([]objectid.ObjectID, error) {
+	leftIdx, err := query.resolveCommitish(left)
+	if err != nil {
+		return nil, err
+	}
+
+	rightIdx, err := query.resolveCommitish(right)
+	if err != nil {
+		return nil, err
+	}
+
+	candidates, err := query.mergeBases(leftIdx, rightIdx)
+	if err != nil {
+		return nil, err
+	}
+
+	slices.SortFunc(candidates, func(left, right nodeIndex) int {
+		switch {
+		case query.commitTime(left) > query.commitTime(right):
+			return -1
+		case query.commitTime(left) < query.commitTime(right):
+			return 1
+		default:
+			return objectid.Compare(query.id(left), query.id(right))
+		}
+	})
+
+	out := make([]objectid.ObjectID, 0, len(candidates))
+	for _, idx := range candidates {
+		out = append(out, query.id(idx))
+	}
+
+	return out, nil
+}