try to fix test 'cmdext:TestFailOnStderr'

cmdext/cmdrunner.go

@@ -133,9 +133,6 @@ func run(opt CommandRunner) (CommandResult, error) {
 
 	case <-stderrFailChan:
 		_ = cmd.Process.Kill()
-		for _, lstr := range opt.listener {
-			lstr.Timeout()
-		}
 
 		if fallback, ok := syncext.ReadChannelWithTimeout(outputChan, 32*time.Millisecond); ok {
 			// most of the time the cmd.Process.Kill() should also have finished the pipereader
@@ -160,7 +157,8 @@ func run(opt CommandRunner) (CommandResult, error) {
 		}
 
 	case outobj := <-outputChan:
-		if exiterr, ok := outobj.err.(*exec.ExitError); ok {
+		var exiterr *exec.ExitError
+		if errors.As(outobj.err, &exiterr) {
 			excode := exiterr.ExitCode()
 			for _, lstr := range opt.listener {
 				lstr.Finished(excode)

cmdext/pipereader.go

@@ -32,8 +32,8 @@ func (pr *pipeReader) Read(listener []CommandListener) (string, string, string,
 	stdout := ""
 	go func() {
 		buf := make([]byte, 128)
-		for true {
-			n, out := pr.stdout.Read(buf)
+		for {
+			n, err := pr.stdout.Read(buf)
 			if n > 0 {
 				txt := string(buf[:n])
 				stdout += txt
@@ -42,11 +42,11 @@ func (pr *pipeReader) Read(listener []CommandListener) (string, string, string,
 					lstr.ReadRawStdout(buf[:n])
 				}
 			}
-			if out == io.EOF {
+			if err == io.EOF {
 				break
 			}
-			if out != nil {
-				errch <- out
+			if err != nil {
+				errch <- err
 				break
 			}
 		}
@@ -61,7 +61,7 @@ func (pr *pipeReader) Read(listener []CommandListener) (string, string, string,
 	stderr := ""
 	go func() {
 		buf := make([]byte, 128)
-		for true {
+		for {
 			n, err := pr.stderr.Read(buf)
 
 			if n > 0 {