Issue #8200: logging: Handle errors when multiprocessing is not fully loaded when logging occurs.

Lib/logging/__init__.py

@@ -287,10 +287,18 @@ class LogRecord(object):
             self.threadName = None
         if not logMultiprocessing:
             self.processName = None
-        elif 'multiprocessing' not in sys.modules:
-            self.processName = 'MainProcess'
         else:
-            self.processName = sys.modules['multiprocessing'].current_process().name
+            self.processName = 'MainProcess'
+            mp = sys.modules.get('multiprocessing')
+            if mp is not None:
+                # Errors may occur if multiprocessing has not finished loading
+                # yet - e.g. if a custom import hook causes third-party code
+                # to run when multiprocessing calls import. See issue 8200
+                # for an example
+                try:
+                    self.processName = mp.current_process().name
+                except StandardError:
+                    pass
         if logProcesses and hasattr(os, 'getpid'):
             self.process = os.getpid()
         else:

Misc/NEWS

@@ -29,6 +29,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #8200: logging: Handle errors when multiprocessing is not
+  fully loaded when logging occurs.
+
 - Issue #3890: Fix recv() and recv_into() on non-blocking SSL sockets.
 
 - Issue #8179: Fix macpath.realpath() on a non-existing path.