Merge pull request google#438 from TomGoBravo/master

update traceplus to work with Python2 and Python3, add example usage

misc/traceplus.py

@@ -1,6 +1,6 @@
 #!/usr/bin/python2.5
 
-# Copyright (C) 2009 Google Inc.
+# Copyright (C) 2018 Google Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,13 +17,7 @@
 """
 Wrapper that makes more useful stack dumps when your script crashes.
 
-Normal use, so that your script works if with or without traceplus:
-if __name__ == '__main__':
-  try:
-    import traceplus
-    traceplus.RunWithExpandedTrace(main)
-  except ImportError:
-    main()
+See traceplus_example.py for a demonstration.
 """
 
 def MakeExpandedTrace(frame_records):
@@ -40,14 +34,18 @@ def MakeExpandedTrace(frame_records):
         else:
           dump.append('     %s' % line)
     for local_name, local_val in frame_obj.f_locals.items():
+      try:
+        local_type_name = type(local_val).__name__
+      except Exception as e:
+        local_type_name = '    Exception in type({}).__name__: {}'.format(local_name, e)
       try:
         truncated_val = repr(local_val)[0:500]
-      except Exception, e:
-        dump.append('    Exception in str(%s): %s\n' % (local_name, e))
+      except Exception as e:
+        dump.append('    Exception in repr({}): {}\n'.format(local_name, e))
       else:
         if len(truncated_val) >= 500:
           truncated_val = '%s...' % truncated_val[0:499]
-        dump.append('    %s = %s\n' % (local_name, truncated_val))
+        dump.append('    {} = {} ({})\n'.format(local_name, truncated_val, local_type_name))
     dump.append('\n')
   return dump
 
@@ -62,21 +60,22 @@ def RunWithExpandedTrace(closure):
     import sys
     import traceback
 
-    # Save trace and exception now. These calls look at the most recently
+    # Save trace and exception now. This call looks at the most recently
     # raised exception. The code that makes the report might trigger other
     # exceptions.
-    original_trace = inspect.trace(3)[1:]
-    formatted_exception = traceback.format_exception_only(*(sys.exc_info()[:2]))
+    exc_type, exc_value, tb = sys.exc_info()
+    frame_records = inspect.getinnerframes(tb, 3)[1:]
+    formatted_exception = traceback.format_exception_only(exc_type, exc_value)
 
     dashes = '%s\n' % ('-' * 60)
     dump = []
     dump.append(dashes)
-    dump.extend(MakeExpandedTrace(original_trace))
+    dump.extend(MakeExpandedTrace(frame_records))
 
 
     dump.append(''.join(formatted_exception))
 
-    print ''.join(dump)
-    print
-    print dashes
+    print(''.join(dump))
+    print()
+    print(dashes)
     sys.exit(127)

misc/traceplus_example.py

@@ -0,0 +1,25 @@
+#!/usr/bin/python3
+
+import argparse
+parser = argparse.ArgumentParser()
+
+def CrashOrNot(crash_commanded):
+  some_value = 1
+  if crash_commanded:
+    some_value -= 1
+  print("All good, you get {}".format(1 / some_value))
+
+def main():
+  parser = argparse.ArgumentParser()
+  parser.add_argument("--crash", help="Do something that causes a crash", action="store_true")
+  args = parser.parse_args()
+  CrashOrNot(args.crash)
+
+# If the traceplus module is found use it, otherwise run main() directly.
+if __name__ == '__main__':
+  try:
+    import traceplus
+  except ImportError:
+    main()
+  else:
+    traceplus.RunWithExpandedTrace(main)

misc/traceplusunittest.py

@@ -0,0 +1,68 @@
+#!/usr/bin/python2.5
+
+# Copyright (C) 2018 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Includes locals in the stacktrace when a failure occurs.
+#
+# Example use:
+#
+# if __name__ == '__main__':
+#   try:
+#     import traceplusunittest
+#   except ImportError:
+#     unittest.main()
+#   else:
+#     traceplusunittest.main()
+
+import unittest
+import traceplus
+import traceback
+import inspect
+
+
+class TextBigStackTestRunner(unittest.TextTestRunner):
+  def _makeResult(self):
+    return TextBigStackTestResult(self.stream, self.descriptions, self.verbosity)
+
+
+class TextBigStackTestResult(unittest._TextTestResult):
+  def _exc_info_to_string(self, err, test):
+    """Converts a sys.exc_info()-style tuple of values into a string."""
+    exctype, value, tb = err
+    # Skip test runner traceback levels
+    while tb and self._is_relevant_tb_level(tb):
+      tb = tb.tb_next
+    if exctype is test.failureException:
+      # Skip assert*() traceback levels
+      length = self._count_relevant_tb_levels(tb)
+      return ''.join(FormatException(exctype, value, tb, length))
+    return ''.join(FormatException(exctype, value, tb))
+
+
+def FormatException(exctype, value, tb, length=None):
+  frame_records = inspect.getinnerframes(tb, 3)
+
+  dump = []
+  if length is None:
+    dump.extend(traceplus.MakeExpandedTrace(frame_records))
+  else:
+    dump.extend(traceplus.MakeExpandedTrace(frame_records[:length]))
+  dump.extend(traceback.format_exception_only(exctype, value))
+  return ''.join(dump)
+
+
+def main():
+  unittest.main(testRunner=TextBigStackTestRunner())
+

misc/traceplusunittest_example.py

@@ -0,0 +1,18 @@
+import unittest
+
+class TestStringMethods(unittest.TestCase):
+
+    def test_upper(self):
+        self.assertEqual('foo'.upper(), 'FOO')
+
+    def test_split(self):
+        s = 'hello world'
+        self.assertEqual(s.split(), ['hello', 'hello'])  # This will fail
+
+if __name__ == '__main__':
+  try:
+    import traceplusunittest
+  except ImportError:
+    unittest.main()
+  else:
+    traceplusunittest.main()