[tor-commits] [stem/master] Revert "Include the originating stacktrace in stem.descriptor.remote exceptions"

[atagar at torproject.org]

commit 8c61fc85a51f9acb65e9fed15bb079a8fad47636
Author: Damian Johnson <atagar at torproject.org>
Date:   Fri Jan 18 10:52:13 2019 -0800

    Revert "Include the originating stacktrace in stem.descriptor.remote exceptions"
    
    Unfortunately in this case the cure is worse than the disease. When dannenberg
    went down this caused stacktraces in DocTor's emails which gives the impression
    the service is having problems...
    
      ERROR: Unable to retrieve the consensus from dannenberg (http://193.23.244.244:80/tor/status-vote/current/consensus): <urlopen error <urlopen error [Errno 111] Connection refused>
    
      Original traceback:
        File "/srv/doctor.torproject.org/doctor/stem/descriptor/remote.py", line 594, in _download_descriptors
          self.content, self.reply_headers = _download_from_dirport(self.download_url, self.compression, timeout)
        File "/srv/doctor.torproject.org/doctor/stem/descriptor/remote.py", line 1043, in _download_from_dirport
          timeout = timeout,
        File "/usr/lib/python2.7/urllib2.py", line 154, in urlopen
          return opener.open(url, data, timeout)
        File "/usr/lib/python2.7/urllib2.py", line 429, in open
          response = self._open(req, data)
        File "/usr/lib/python2.7/urllib2.py", line 447, in _open
          '_open', req)
        File "/usr/lib/python2.7/urllib2.py", line 407, in _call_chain
          result = func(*args)
        File "/usr/lib/python2.7/urllib2.py", line 1228, in http_open
          return self.do_open(httplib.HTTPConnection, req)
        File "/usr/lib/python2.7/urllib2.py", line 1198, in do_open
          raise URLError(err)
      URLError: <urlopen error [Errno 111] Connection refused>
    
    I'm kinda torn on this change. On one hand it's usful information for unusual
    errors, but on the other it's troubling looking bloat for mundane things like
    this.
    
    Encoding a stacktrace within an encepiton message was definitely an icky hack
    so simply reverting this for now. Most likely we'll simply need to live without
    underlying stacktraces until we drop python 2.x support.
    
    This reverts commit cc43a6ca90e3943a542258b2b4d8466ae9a4ac36.
---
 stem/descriptor/remote.py | 33 +--------------------------------
 1 file changed, 1 insertion(+), 32 deletions(-)

diff --git a/stem/descriptor/remote.py b/stem/descriptor/remote.py
index 9ccfaced..9eb639ad 100644
--- a/stem/descriptor/remote.py
+++ b/stem/descriptor/remote.py
@@ -97,7 +97,6 @@ import random
 import sys
 import threading
 import time
-import traceback
 import zlib
 
 import stem
@@ -467,13 +466,6 @@ class Query(object):
     Blocks until our request is complete then provides the descriptors. If we
     haven't yet started our request then this does so.
 
-    .. versionchanged:: 1.8.0
-       Overwriting exceptions to include the originating traceback.
-
-       In Stem 2.x (when we no longer need Python 2.x compatibility) this will
-       revert back to re-raising the originating exception, but with its
-       stacktrace preserved.
-
     :param bool suppress: avoids raising exceptions if **True**
 
     :returns: list for the requested :class:`~stem.descriptor.__init__.Descriptor` instances
@@ -483,7 +475,6 @@ class Query(object):
       **False**...
 
         * **ValueError** if the descriptor contents is malformed
-        * **stem.ProtocolError** if unable to parse an ORPort response
         * **socket.timeout** if our request timed out
         * **urllib2.URLError** for most request failures
 
@@ -502,27 +493,7 @@ class Query(object):
         if suppress:
           return
 
-        # TODO: Unfortunately the proper way to retain a stacktrace differs
-        # between python 2.x and 3.x in a syntactic way...
-        #
-        #   Python 2.x
-        #
-        #     raise exc_type, exc_value, exc_traceback
-        #
-        #   Python 3.x
-        #
-        #     raise WrapperException('foo') from exc_value
-        #
-        # Because this is syntactic we cannot do an 'if python2, else python3'
-        # for this. As such re-encoding the stacktrace as part of the message.
-        #
-        # When we drop python 2.x support we should replace this with the
-        # 'raise from' option above.
-
-        exc_type, exc_value, exc_traceback = self._error_attr
-        stacktrace = 'Original traceback:\n' + ''.join(traceback.format_exception(exc_type, exc_value, exc_traceback)[1:])
-
-        raise exc_type(str(exc_value) + '\n\n' + stacktrace)
+        raise self.error
       else:
         if self.content is None:
           if suppress:
@@ -554,7 +525,6 @@ class Query(object):
             yield desc
         except ValueError as exc:
           self.error = exc  # encountered a parsing error
-          self._error_attr = sys.exc_info()
 
           if suppress:
             return
@@ -609,7 +579,6 @@ class Query(object):
       else:
         log.debug("Unable to download descriptors from '%s': %s" % (self.download_url, exc))
         self.error = exc
-        self._error_attr = sys.exc_info()
     finally:
       self.is_done = True