ipc: Avoid using QLocalServer.setSocketOptions.

This causes problems with AddressInUseError being swallowed.

Fixes #997.

qutebrowser/misc/ipc.py

@@ -183,7 +183,7 @@ class IPCServer(QObject):
         self._server.newConnection.connect(self.handle_connection)
 
         self._socket = None
-        self._socketopts_ok = os.name == 'nt' or qtutils.version_check('5.4')
+        self._socketopts_ok = os.name == 'nt'
         if self._socketopts_ok:  # pragma: no cover
             # If we use setSocketOptions on Unix with Qt < 5.4, we get a
             # NameError while listening...
@@ -213,7 +213,13 @@ class IPCServer(QObject):
                 raise ListenError(self._server)
         if not self._socketopts_ok:  # pragma: no cover
             # If we use setSocketOptions on Unix with Qt < 5.4, we get a
-            # NameError while listening...
+            # NameError while listening.
+            # (see b135569d5c6e68c735ea83f42e4baf51f7972281)
+            #
+            # Also, we don't get an AddressInUseError with Qt 5.5:
+            # https://bugreports.qt.io/browse/QTBUG-48635
+            #
+            # This means we only use setSocketOption on Windows...
             os.chmod(self._server.fullServerName(), 0o700)
 
     @pyqtSlot(int)

tests/unit/misc/test_ipc.py

@@ -299,8 +299,6 @@ class TestListen:
             ipc_server.listen()
 
     @pytest.mark.posix
-    @pytest.mark.xfail(reason="Fails since adding setSocketOptions to "
-                       "IPCServer.")
     def test_in_use(self, qlocalserver, ipc_server, monkeypatch):
         monkeypatch.setattr('qutebrowser.misc.ipc.QLocalServer.removeServer',
                             lambda self: True)
@@ -896,3 +894,25 @@ def test_socket_options_listen_problem(qlocalserver, short_tmpdir):
         assert not ok
         assert qlocalserver.serverError() == QAbstractSocket.HostNotFoundError
         assert qlocalserver.errorString() == 'QLocalServer::listen: Name error'
+
+
+@pytest.mark.posix
+def test_socket_options_address_in_use_problem(qlocalserver, short_tmpdir):
+    """Qt seems to ignore AddressInUseError when using socketOptions.
+
+    With this test we verify this bug still exists. If it fails, we can
+    probably start using setSocketOptions again.
+    """
+    servername = str(short_tmpdir / 'x')
+
+    s1 = QLocalServer()
+    ok = s1.listen(servername)
+    assert ok
+
+    s2 = QLocalServer()
+    s2.setSocketOptions(QLocalServer.UserAccessOption)
+    ok = s2.listen(servername)
+    print(s2.errorString())
+    # We actually would expect ok == False here - but we want the test to fail
+    # when the Qt bug is fixed.
+    assert ok