From 6fd0520db3cffad4fd01c98319b9b1bf3c50f5e2 Mon Sep 17 00:00:00 2001
From: "Bryan C. Mills" <bcmills@google.com>
Date: Tue, 10 May 2022 09:07:34 -0400
Subject: [PATCH] os/exec: eliminate some arbitrary short timeouts

These tests appear to be using timeouts to check for deadlocks or to
cause the test to fail earlier. However, on slower machines these
short timeouts can cause spurious failures, and even on faster
machines if the test locks up we usually want a goroutine dump instead
of a short failure message anyway.

Fixes #52818 (maybe).

Change-Id: Ib8f18d679f9443721e8a924caef6dc8d214fca1b
Reviewed-on: https://go-review.googlesource.com/c/go/+/405434
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
---
 src/os/exec/exec_test.go | 77 ++++++++++------------------------------
 1 file changed, 19 insertions(+), 58 deletions(-)

diff --git a/src/os/exec/exec_test.go b/src/os/exec/exec_test.go
index 9cc14bdaca..8f79b19eb6 100644
--- a/src/os/exec/exec_test.go
+++ b/src/os/exec/exec_test.go
@@ -265,24 +265,13 @@ func cmdExtraFilesAndPipes(args ...string) {
 	}
 	response := ""
 	for i, r := range pipes {
-		ch := make(chan string, 1)
-		go func(c chan string) {
-			buf := make([]byte, 10)
-			n, err := r.Read(buf)
-			if err != nil {
-				fmt.Fprintf(os.Stderr, "Child: read error: %v on pipe %d\n", err, i)
-				os.Exit(1)
-			}
-			c <- string(buf[:n])
-			close(c)
-		}(ch)
-		select {
-		case m := <-ch:
-			response = response + m
-		case <-time.After(5 * time.Second):
-			fmt.Fprintf(os.Stderr, "Child: Timeout reading from pipe: %d\n", i)
+		buf := make([]byte, 10)
+		n, err := r.Read(buf)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Child: read error: %v on pipe %d\n", err, i)
 			os.Exit(1)
 		}
+		response = response + string(buf[:n])
 	}
 	fmt.Fprintf(os.Stderr, "child: %s", response)
 }
@@ -699,25 +688,15 @@ func TestExtraFilesFDShuffle(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Run: %v", err)
 	}
-	ch := make(chan string, 1)
-	go func(ch chan string) {
-		buf := make([]byte, 512)
-		n, err := stderr.Read(buf)
-		if err != nil {
-			t.Errorf("Read: %s", err)
-			ch <- err.Error()
-		} else {
-			ch <- string(buf[:n])
-		}
-		close(ch)
-	}(ch)
-	select {
-	case m := <-ch:
-		if m != expected {
+
+	buf := make([]byte, 512)
+	n, err := stderr.Read(buf)
+	if err != nil {
+		t.Errorf("Read: %s", err)
+	} else {
+		if m := string(buf[:n]); m != expected {
 			t.Errorf("Read: '%s' not '%s'", m, expected)
 		}
-	case <-time.After(5 * time.Second):
-		t.Errorf("Read timedout")
 	}
 	c.Wait()
 }
@@ -949,19 +928,9 @@ func (w *badWriter) Write(data []byte) (int, error) {
 func TestClosePipeOnCopyError(t *testing.T) {
 	cmd := helperCommand(t, "yes")
 	cmd.Stdout = new(badWriter)
-	c := make(chan int, 1)
-	go func() {
-		err := cmd.Run()
-		if err == nil {
-			t.Errorf("yes completed successfully")
-		}
-		c <- 1
-	}()
-	select {
-	case <-c:
-		// ok
-	case <-time.After(5 * time.Second):
-		t.Fatalf("yes got stuck writing to bad writer")
+	err := cmd.Run()
+	if err == nil {
+		t.Errorf("yes unexpectedly completed successfully")
 	}
 }
 
@@ -1002,18 +971,10 @@ func TestContext(t *testing.T) {
 	if n != len(buf) || err != nil || string(buf) != "O:hi\n" {
 		t.Fatalf("ReadFull = %d, %v, %q", n, err, buf[:n])
 	}
-	waitErr := make(chan error, 1)
-	go func() {
-		waitErr <- c.Wait()
-	}()
-	cancel()
-	select {
-	case err := <-waitErr:
-		if err == nil {
-			t.Fatal("expected Wait failure")
-		}
-	case <-time.After(3 * time.Second):
-		t.Fatal("timeout waiting for child process death")
+	go cancel()
+
+	if err := c.Wait(); err == nil {
+		t.Fatal("expected Wait failure")
 	}
 }
 
-- 
2.50.0