#5287: Add exception handling around findCaller() call to help out IronPython.

Lib/logging/__init__.py

@@ -1128,7 +1128,12 @@ def _log(self, level, msg, args, exc_info=None, extra=None):
         all the handlers of this logger to handle the record.
         """
         if _srcfile:
-            fn, lno, func = self.findCaller()
+            #IronPython doesn't track Python frames, so findCaller throws an
+            #exception. We trap it here so that IronPython can use logging.
+            try:
+                fn, lno, func = self.findCaller()
+            except ValueError:
+                fn, lno, func = "(unknown file)", 0, "(unknown function)"
         else:
             fn, lno, func = "(unknown file)", 0, "(unknown function)"
         if exc_info:

Misc/NEWS

@@ -161,16 +161,18 @@ Core and Builtins
 
 Library
 -------
+- Issue #5287: Add exception handling around findCaller() call to help out
+  IronPython.
 
 - Issue #5282: Fixed mmap resize on 32bit windows and unix. When offset > 0,
   The file was resized to wrong size.
 
 - Issue #5292: Fixed mmap crash on its boundary access m[len(m)].
 
-- Issue #2279: distutils.sdist.add_defaults now add files 
+- Issue #2279: distutils.sdist.add_defaults now add files
   from the package_data and the data_files metadata.
 
-- Issue #5257: refactored all tests in distutils, so they use 
+- Issue #5257: refactored all tests in distutils, so they use
   support.TempdirManager, to avoid writing in the tests directory.
 
 - Issue #4524: distutils build_script command failed with --with-suffix=3.