Improve exception handling.

trace_inputs.py

 #!/usr/bin/env python
 # coding=utf-8
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Traces an executable and its child processes and extract the files accessed
 by them.
 
 The implementation uses OS-specific API. The native Kernel logger and the ETL
@@ skipping 1484 matching lines @@
       try:
         context = cls.Context(blacklist, item['cwd'])
         for pidfile in glob.iglob('%s.%s.*' % (logname, item['trace'])):
           pid = pidfile.rsplit('.', 1)[1]
           if pid.isdigit():
             pid = int(pid)
             # TODO(maruel): Load as utf-8
             for line in open(pidfile, 'rb'):
               context.on_line(pid, line)
         result['results'] = context.to_results()
-      except TracingFailure, e:
-        result['exception'] = e
+      except TracingFailure:
+        result['exception'] = sys.exc_info()
       out.append(result)
     return out
 
 
 class Dtrace(ApiBase):
   """Uses DTrace framework through dtrace. Requires root access.
 
   Implies Mac OSX.
 
   dtruss can't be used because it has compatibility issues with python.
@@ skipping 1518 matching lines @@
   - logfile: File to load.
   - root_dir: Root directory to use to determine if a file is relevant to the
               trace or not.
   - api: A tracing api instance.
   - blacklist: Optional blacklist function to filter out unimportant files.
   """
   data = api.parse_log(logfile, (blacklist or (lambda _: False)))
   assert len(data) == 1, 'More than one trace was detected!'
   if 'exception' in data[0]:
     # It got an exception, raise it.
-    raise data[0]['exception']
+    raise \

[csharp, 2012/10/15 15:38:28]

Would it be better to use brackets, or does raise have to be on 1 python line?

[M-A Ruel, 2012/10/15 15:40:25]

It didn't work when I used (). :/
It's really an ancestral feature.

+        data[0]['exception'][0], \
+        data[0]['exception'][1], \
+        data[0]['exception'][2]
   results = data[0]['results']
   if root_dir:
     results = results.strip_root(root_dir)
   return results
 
 
 def CMDclean(args):
   """Cleans up traces."""
   parser = OptionParserTraceInputs(command='clean')
   options, args = parser.parse_args(args)
@@ skipping 51 matching lines @@
 
   variables = dict(options.variables)
   api = get_api()
   def blacklist(f):
     return any(re.match(b, f) for b in options.blacklist)
   data = api.parse_log(options.log, blacklist)
   # Process each trace.
   output_as_json = []
   for item in data:
     if 'exception' in item:
+      # Do not abort the other traces.
       print >> sys.stderr, (
-          'Trace %s: Got an exception: %s' % (item['trace'], item['exception']))
+          'Trace %s: Got an exception: %s' % (
+            item['trace'], item['exception'][1]))
       continue
     results = item['results']
     if options.root_dir:
       results = results.strip_root(options.root_dir)
 
     if options.json:
       output_as_json.append(results.flatten())
     else:
       simplified = extract_directories(
           options.root_dir, results.files, blacklist)
@@ skipping 120 matching lines @@
     main_impl(argv)
   except TracingFailure, e:
     sys.stderr.write('\nError: ')
     sys.stderr.write(str(e))
     sys.stderr.write('\n')
     return 1
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))