os/signal: don't ignore SIGINT in TestAtomicStop child process

Fixes #35085

Change-Id: Ice611e1223392f687061a43fd4c2298ea22774fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/207081
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

diff --git a/src/os/signal/signal_test.go b/src/os/signal/signal_test.go
index d9305a4b867dba011c02618295fe0d538384de0f..a4489ffd3ee0de0bdf660a8f1afa837941e9af63 100644 (file)
--- a/src/os/signal/signal_test.go
+++ b/src/os/signal/signal_test.go
@@ -422,6 +422,19 @@ func TestAtomicStop(t *testing.T) {
 
        testenv.MustHaveExec(t)
 
+       // Call Notify for SIGINT before starting the child process.
+       // That ensures that SIGINT is not ignored for the child.
+       // This is necessary because if SIGINT is ignored when a
+       // Go program starts, then it remains ignored, and closing
+       // the last notification channel for SIGINT will switch it
+       // back to being ignored. In that case the assumption of
+       // atomicStopTestProgram, that it will either die from SIGINT
+       // or have it be reported, breaks down, as there is a third
+       // option: SIGINT might be ignored.
+       cs := make(chan os.Signal, 1)
+       Notify(cs, syscall.SIGINT)
+       defer Stop(cs)
+
        const execs = 10
        for i := 0; i < execs; i++ {
                timeout := "0"
@@ -466,6 +479,12 @@ func TestAtomicStop(t *testing.T) {
 // It tries to trigger a signal delivery race. This function should
 // either catch a signal or die from it.
 func atomicStopTestProgram() {
+       // This test won't work if SIGINT is ignored here.
+       if Ignored(syscall.SIGINT) {
+               fmt.Println("SIGINT is ignored")
+               os.Exit(1)
+       }
+
        const tries = 10
 
        timeout := 2 * time.Second