testing: reject calls to Run within Cleanup callbacks

Calling t.Run inside t.Cleanup can mess up the execution order of
registered Cleanup callbacks. Reject calls to Run within Cleanup
callbacks.

Fixes #48515

Change-Id: I61e4cb35253db1a8bbe3351d59055433030aa289
Reviewed-on: https://go-review.googlesource.com/c/go/+/352349
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Joedian Reid <joedian@golang.org>
Run-TryBot: Changkun Ou <mail@changkun.de>
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/src/testing/panic_test.go b/src/testing/panic_test.go
index fafcff790e..4648057b77 100644
--- a/src/testing/panic_test.go
+++ b/src/testing/panic_test.go
@@ -224,6 +224,11 @@ func TestMorePanic(t *testing.T) {
 			want: `panic: die
 	panic: test executed panic(nil) or runtime.Goexit`,
 		},
+		{
+			desc:  "Issue 48515: call t.Run in t.Cleanup should trigger panic",
+			flags: []string{"-test.run=TestCallRunInCleanupHelper"},
+			want:  `panic: testing: t.Run is called during t.Cleanup`,
+		},
 	}
 
 	for _, tc := range testCases {
@@ -239,6 +244,18 @@ func TestMorePanic(t *testing.T) {
 	}
 }
 
+func TestCallRunInCleanupHelper(t *testing.T) {
+	if os.Getenv("GO_WANT_HELPER_PROCESS") != "1" {
+		return
+	}
+
+	t.Cleanup(func() {
+		t.Run("in-cleanup", func(t *testing.T) {
+			t.Log("must not be executed")
+		})
+	})
+}
+
 func TestGoexitInCleanupAfterPanicHelper(t *testing.T) {
 	if os.Getenv("GO_WANT_HELPER_PROCESS") != "1" {
 		return