Impose verbosity limit when formatting map keys (#248)

Map keys should have a sensible verbosity limit imposed,
otherwise the reporter can end up printing a massive data structure
that cannot reasonably fit in memory.

1 files changed, 11 insertions, 0 deletions

diff --git a/cmp/compare_test.go b/cmp/compare_test.go
index 13a3a4e..84f7353 100644
--- a/cmp/compare_test.go
+++ b/cmp/compare_test.go
@@ -1276,6 +1276,17 @@ using the AllowUnexported option.`, "\n"),
 		y:         MyComposite{},
 		wantEqual: false,
 		reason:    "batched diffing for empty slices and nil slices",
+	}, {
+		label: label + "/LargeMapKey",
+		x: map[*[]byte]int{func() *[]byte {
+			b := make([]byte, 1<<20, 1<<20)
+			return &b
+		}(): 0},
+		y: map[*[]byte]int{func() *[]byte {
+			b := make([]byte, 1<<20, 1<<20)
+			return &b
+		}(): 0},
+		reason: "printing map keys should have some verbosity limit imposed",
 	}}
 }