.

wcfs/δbtail.go

@@ -394,17 +394,18 @@ func diffX(ctx context.Context, a, b Node, δZTC SetOid) (δ map[Key]Value, err
 */
 	var aT, bT *Tree
 	var aB, bB *Bucket
+	isT := false
 
 	if a != nil {
-		aT, _ = a.(*Tree)
-		aB, _ = a.(*Bucket)
+		aT, isT = a.(*Tree)
+		aB, _   = a.(*Bucket)
 		if (aT == nil && aB == nil) {
 			panicf("a: bad type %T", a)
 		}
 	}
 	if b != nil {
-		bT, _ = b.(*Tree)
-		bB, _ = b.(*Bucket)
+		bT, isT = b.(*Tree)
+		bB, _   = b.(*Bucket)
 		if (bT == nil && bB == nil) {
 			panicf("b: bad type %T", b)
 		}
@@ -420,8 +421,11 @@ func diffX(ctx context.Context, a, b Node, δZTC SetOid) (δ map[Key]Value, err
 		}
 	}
 
-
-	panic("TODO")
+	if isT {
+		return diffT(ctx, aT, bT, δZTC)
+	} else {
+		return diffB(ctx, aB, bB)
+	}
 }
 
 // diffT computes difference in between two revisions of a tree's subtree.