server: fix failingListener data race in tests

WARNING: DATA RACE Read at 0x00c00002b788 by goroutine 44: github.com/emersion/go-smtp_test.(*failingListener).Close() /home/simon/src/go-smtp/server_test.go:193 +0x34 github.com/emersion/go-smtp.(*Server).Close() /home/simon/src/go-smtp/server.go:251 +0x181 github.com/emersion/go-smtp_test.TestServerAcceptErrorHandling() /home/simon/src/go-smtp/server_test.go:323 +0x771 testing.tRunner() /usr/lib/go/src/testing/testing.go:1689 +0x21e testing.(*T).Run.gowrap1() /usr/lib/go/src/testing/testing.go:1742 +0x44 Previous write at 0x00c00002b788 by goroutine 45: github.com/emersion/go-smtp_test.(*failingListener).Close() /home/simon/src/go-smtp/server_test.go:195 +0xdb github.com/emersion/go-smtp_test.TestServerAcceptErrorHandling.func1() /home/simon/src/go-smtp/server_test.go:316 +0xab Goroutine 44 (running) created at: testing.(*T).Run() /usr/lib/go/src/testing/testing.go:1742 +0x825 testing.runTests.func1() /usr/lib/go/src/testing/testing.go:2161 +0x85 testing.tRunner() /usr/lib/go/src/testing/testing.go:1689 +0x21e testing.runTests() /usr/lib/go/src/testing/testing.go:2159 +0x8be testing.(*M).Run() /usr/lib/go/src/testing/testing.go:2027 +0xf17 main.main() _testmain.go:163 +0x2bd Goroutine 45 (finished) created at: github.com/emersion/go-smtp_test.TestServerAcceptErrorHandling() /home/simon/src/go-smtp/server_test.go:314 +0x5d5 testing.tRunner() /usr/lib/go/src/testing/testing.go:1689 +0x21e testing.(*T).Run.gowrap1() /usr/lib/go/src/testing/testing.go:1742 +0x44
emersion · Apr 17, 2024 · 6f31b3a · 6f31b3a
1 parent 029f751
commit 6f31b3a
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/server_test.go b/server_test.go
@@ -10,6 +10,7 @@ import (
 	"log"
 	"net"
 	"strings"
+	"sync"
 	"testing"
 
 	"github.com/emersion/go-sasl"
@@ -173,13 +174,17 @@ func (s *session) LMTPData(r io.Reader, collector smtp.StatusCollector) error {
 type failingListener struct {
 	c      chan error
 	closed bool
+	mu     sync.Mutex
 }
 
 func newFailingListener() *failingListener {
 	return &failingListener{c: make(chan error)}
 }
 
 func (l *failingListener) Send(err error) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
 	if !l.closed {
 		l.c <- err
 	}
@@ -190,6 +195,9 @@ func (l *failingListener) Accept() (net.Conn, error) {
 }
 
 func (l *failingListener) Close() error {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
 	if !l.closed {
 		close(l.c)
 		l.closed = true