fixup! TerminalReporter: remove _session

Author: blueyed

src/_pytest/terminal.py

@@ -469,8 +469,11 @@ def pytest_runtest_logreport(self, report: TestReport) -> None:
     def _is_last_item(self):
         return len(self._progress_nodeids_reported) == self._testscollected
 
-    def pytest_xdist_node_collection_finished(self, node, ids):
-        self._testscollected = len(ids)
+    # XXX
+    if "xdist" in sys.modules:
+
+        def pytest_xdist_node_collection_finished(self, node, ids):
+            self._testscollected = len(ids)
 
     def pytest_runtest_logfinish(self, nodeid):
         if self.verbosity <= 0 and self._show_progress_info: