fix race in test setup/teardown

not easily triggered, but it happened just now on a build server.

ctl_test.go

@@ -38,8 +38,7 @@ func TestCtl(t *testing.T) {
 	if errs := mox.LoadConfig(ctxbg, true, false); len(errs) > 0 {
 		t.Fatalf("loading mox config: %v", errs)
 	}
-	switchDone := store.Switchboard()
-	defer close(switchDone)
+	defer store.Switchboard()()
 
 	xlog := mlog.New("ctl")
 

imapserver/fuzz_test.go

@@ -71,8 +71,7 @@ func FuzzServer(f *testing.F) {
 	if err != nil {
 		f.Fatalf("set password: %v", err)
 	}
-	done := store.Switchboard()
-	defer close(done)
+	defer store.Switchboard()()
 
 	comm := store.RegisterComm(acc)
 	defer comm.Unregister()

imapserver/server_test.go

@@ -346,11 +346,9 @@ func startArgs(t *testing.T, first, isTLS, allowLoginWithoutTLS bool) *testconn
 		err = acc.SetPassword("testtest")
 		tcheck(t, err, "set password")
 	}
-	var switchDone chan struct{}
+	switchStop := func() {}
 	if first {
-		switchDone = store.Switchboard()
-	} else {
-		switchDone = make(chan struct{}) // Dummy, that can be closed.
+		switchStop = store.Switchboard()
 	}
 
 	serverConn, clientConn := net.Pipe()
@@ -368,7 +366,7 @@ func startArgs(t *testing.T, first, isTLS, allowLoginWithoutTLS bool) *testconn
 	cid := connCounter
 	go func() {
 		serve("test", cid, tlsConfig, serverConn, isTLS, allowLoginWithoutTLS)
-		close(switchDone)
+		switchStop()
 		close(done)
 	}()
 	client, err := imapclient.New(clientConn, true)

import.go

@@ -118,8 +118,7 @@ func xcmdXImport(mbox bool, c *cmd) {
 	mox.Conf.Dynamic.Accounts = map[string]config.Account{
 		account: {},
 	}
-	switchDone := store.Switchboard()
-	defer close(switchDone)
+	defer store.Switchboard()()
 
 	xlog := mlog.New("import")
 	cconn, sconn := net.Pipe()

queue/queue_test.go

@@ -45,14 +45,14 @@ func setup(t *testing.T) (*store.Account, func()) {
 	tcheck(t, err, "open account")
 	err = acc.SetPassword("testtest")
 	tcheck(t, err, "set password")
-	switchDone := store.Switchboard()
+	switchStop := store.Switchboard()
 	mox.Shutdown, mox.ShutdownCancel = context.WithCancel(ctxbg)
 	return acc, func() {
 		acc.Close()
 		mox.ShutdownCancel()
 		mox.Shutdown, mox.ShutdownCancel = context.WithCancel(ctxbg)
 		Shutdown()
-		close(switchDone)
+		switchStop()
 	}
 }
 

serve.go

@@ -624,7 +624,8 @@ func start(mtastsdbRefresher, skipForkExec bool) error {
 	http.Serve()
 
 	go func() {
-		<-store.Switchboard()
+		store.Switchboard()
+		<-make(chan struct{})
 	}()
 	return nil
 }

smtpserver/fuzz_test.go

@@ -43,8 +43,7 @@ func FuzzServer(f *testing.F) {
 	if err != nil {
 		f.Fatalf("set password: %v", err)
 	}
-	done := store.Switchboard()
-	defer close(done)
+	defer store.Switchboard()()
 	err = queue.Init()
 	if err != nil {
 		f.Fatalf("queue init: %v", err)

smtpserver/server_test.go

@@ -75,7 +75,7 @@ test email
 type testserver struct {
 	t          *testing.T
 	acc        *store.Account
-	switchDone chan struct{}
+	switchStop func()
 	comm       *store.Comm
 	cid        int64
 	resolver   dns.Resolver
@@ -101,7 +101,7 @@ func newTestServer(t *testing.T, configPath string, resolver dns.Resolver) *test
 	tcheck(t, err, "open account")
 	err = ts.acc.SetPassword("testtest")
 	tcheck(t, err, "set password")
-	ts.switchDone = store.Switchboard()
+	ts.switchStop = store.Switchboard()
 	err = queue.Init()
 	tcheck(t, err, "queue init")
 
@@ -116,7 +116,7 @@ func (ts *testserver) close() {
 	}
 	ts.comm.Unregister()
 	queue.Shutdown()
-	close(ts.switchDone)
+	ts.switchStop()
 	err := ts.acc.Close()
 	tcheck(ts.t, err, "closing account")
 	ts.acc = nil

store/account_test.go

@@ -36,8 +36,7 @@ func TestMailbox(t *testing.T) {
 		err = acc.Close()
 		tcheck(t, err, "closing account")
 	}()
-	switchDone := Switchboard()
-	defer close(switchDone)
+	defer Switchboard()()
 
 	log := mlog.New("store")
 

store/export_test.go

@@ -25,8 +25,7 @@ func TestExport(t *testing.T) {
 	acc, err := OpenAccount("mjl")
 	tcheck(t, err, "open account")
 	defer acc.Close()
-	switchDone := Switchboard()
-	defer close(switchDone)
+	defer Switchboard()()
 
 	log := mlog.New("export")
 

store/state.go

@@ -101,7 +101,7 @@ type ChangeMailboxKeywords struct {
 var switchboardBusy atomic.Bool
 
 // Switchboard distributes changes to accounts to interested listeners. See Comm and Change.
-func Switchboard() chan struct{} {
+func Switchboard() (stop func()) {
 	regs := map[*Account]map[*Comm]struct{}{}
 	done := make(chan struct{})
 
@@ -145,14 +145,18 @@ func Switchboard() chan struct{} {
 				chReq.done <- struct{}{}
 
 			case <-done:
-				if !switchboardBusy.CompareAndSwap(true, false) {
-					panic("switchboard already unregistered?")
-				}
+				done <- struct{}{}
 				return
 			}
 		}
 	}()
-	return done
+	return func() {
+		done <- struct{}{}
+		<-done
+		if !switchboardBusy.CompareAndSwap(true, false) {
+			panic("switchboard already unregistered?")
+		}
+	}
 }
 
 // Comm handles communication with the goroutine that maintains the

webaccount/account_test.go

@@ -46,8 +46,7 @@ func TestAccount(t *testing.T) {
 		err = acc.Close()
 		tcheck(t, err, "closing account")
 	}()
-	switchDone := store.Switchboard()
-	defer close(switchDone)
+	defer store.Switchboard()()
 
 	log := mlog.New("store")
 

webmail/api_test.go

@@ -45,8 +45,7 @@ func TestAPI(t *testing.T) {
 	mox.Context = ctxbg
 	mox.ConfigStaticPath = "../testdata/webmail/mox.conf"
 	mox.MustLoadConfig(true, false)
-	switchDone := store.Switchboard()
-	defer close(switchDone)
+	defer store.Switchboard()()
 
 	acc, err := store.OpenAccount("mjl")
 	tcheck(t, err, "open account")

webmail/view_test.go

@@ -25,8 +25,7 @@ func TestView(t *testing.T) {
 	mox.Context = ctxbg
 	mox.ConfigStaticPath = "../testdata/webmail/mox.conf"
 	mox.MustLoadConfig(true, false)
-	switchDone := store.Switchboard()
-	defer close(switchDone)
+	defer store.Switchboard()()
 
 	acc, err := store.OpenAccount("mjl")
 	tcheck(t, err, "open account")

webmail/webmail_test.go

@@ -266,8 +266,7 @@ func TestWebmail(t *testing.T) {
 	mox.Context = ctxbg
 	mox.ConfigStaticPath = "../testdata/webmail/mox.conf"
 	mox.MustLoadConfig(true, false)
-	switchDone := store.Switchboard()
-	defer close(switchDone)
+	defer store.Switchboard()()
 
 	acc, err := store.OpenAccount("mjl")
 	tcheck(t, err, "open account")