capturemock scans sys.modules, which can interact badly with six module

[Marc Abramowitz]

The six module has something called six.moves which creates fake module objects in sys.modules that are proxies that lazy load the real modules.

When I use six and capturemock together, I get errors because capturemock scans through all the modules in sys.modules and sometimes chokes on one of them:

```
 ❯ py.test -k test_get_all_unresolved --maxfail=1 tests/functional/test_entity_correction.py
Test session starts (darwin, 2.6.7)
plugins: capturelog, cov, sugar

―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――― TestEntityAttributesUnverified.test_get_all_unresolved ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――
../../lib/python2.6/site-packages/capturemock/__init__.py:210: in wrapped_func
> interceptor = interceptPython(self.mode, recordFile, replayFile, self.rcFiles, self.pythonAttrs)
../../lib/python2.6/site-packages/capturemock/capturepython.py:221: in interceptPython
> handler.makeIntercepts()
../../lib/python2.6/site-packages/capturemock/capturepython.py:281: in makeIntercepts
> import_handler = ImportHandler(fullIntercepts, callStackChecker, trafficHandler)
../../lib/python2.6/site-packages/capturemock/capturepython.py:84: in __init__
> self.handleImportedModules()
../../lib/python2.6/site-packages/capturemock/capturepython.py:92: in handleImportedModules
> loadingMods = self.modulesLoading(currModName, modName)
../../lib/python2.6/site-packages/capturemock/capturepython.py:131: in modulesLoading
> modAttrName = self.findAttribute(otherMod, oldModule)
../../lib/python2.6/site-packages/capturemock/capturepython.py:140: in findAttribute
> if getattr(module, currAttrName) is attr:
../../lib/python2.6/site-packages/six.py:90: in __get__
> raise AttributeError("%s could not be imported " % self.name)
E AttributeError: dbm_gnu could not be imported
```

Here's a patch that makes CaptureMock not error out if it can find an attribute it was expecting to find:

```
diff --git a/capturepython.py.2014-04-29-143822 b/capturepython.py
index 0483931..3ac8060 100644
--- a/capturepython.py.2014-04-29-143822
+++ b/capturepython.py
@@ -137,7 +137,7 @@ class ImportHandler:
         # Can't assume the attribute will have the same name of the module,
         # because of "import x as y" construct
         for currAttrName in dir(module):
- if getattr(module, currAttrName) is attr:
+ if getattr(module, currAttrName, None) is attr:
                 return currAttrName

     def shouldIntercept(self, name):
```

[Geoff Bache (geoff.bache)]

Integrated the suggested patch. Let me know if it's OK and I'll release 1.0.2. (I fixed a few other things last week)

[Marc Abramowitz (msabramo)]

Testing out your recent change -- here's the before and after:

$ bzr update -r 4662
 M capturemock/capturepython.py
All changes applied successfully.
Updated to revision 4662 of branch /Users/marca/dev/surveymonkey/profilesvc/src/capturemock

$ python foobar.py
Traceback (most recent call last):
  File "foobar.py", line 10, in <module>
    foo()
  File "/Users/marca/dev/surveymonkey/profilesvc/src/capturemock/capturemock/__init__.py", line 210, in wrapped_func
    interceptor = interceptPython(self.mode, recordFile, replayFile, self.rcFiles, self.pythonAttrs)
  File "/Users/marca/dev/surveymonkey/profilesvc/src/capturemock/capturemock/capturepython.py", line 221, in interceptPython
    handler.makeIntercepts()
  File "/Users/marca/dev/surveymonkey/profilesvc/src/capturemock/capturemock/capturepython.py", line 281, in makeIntercepts
    import_handler = ImportHandler(fullIntercepts, callStackChecker, trafficHandler)
  File "/Users/marca/dev/surveymonkey/profilesvc/src/capturemock/capturemock/capturepython.py", line 84, in __init__
    self.handleImportedModules()
  File "/Users/marca/dev/surveymonkey/profilesvc/src/capturemock/capturemock/capturepython.py", line 92, in handleImportedModules
    loadingMods = self.modulesLoading(currModName, modName)
  File "/Users/marca/dev/surveymonkey/profilesvc/src/capturemock/capturemock/capturepython.py", line 131, in modulesLoading
    modAttrName = self.findAttribute(otherMod, oldModule)
  File "/Users/marca/dev/surveymonkey/profilesvc/src/capturemock/capturemock/capturepython.py", line 140, in findAttribute
    if getattr(module, currAttrName) is attr:
  File "/Users/marca/dev/surveymonkey/profilesvc/lib/python2.6/site-packages/six.py", line 90, in __get__
    raise AttributeError("%s could not be imported " % self.name)
AttributeError: dbm_gnu could not be imported

$ bzr update
 M capturemock/capturepython.py
All changes applied successfully.
Updated to revision 4663 of branch /Users/marca/dev/surveymonkey/profilesvc/src/capturemock

$ python foobar.py
WARNING: having to reset the variable '__main__.sqlalchemy'.
This implies you are intercepting the module 'sqlalchemy' after importing it.
While this might work, it may well be very slow and is not recommended.

WARNING: having to reset the variable '__main__.sqlalchemy'.
This implies you are intercepting the module 'sqlalchemy' after importing it.
While this might work, it may well be very slow and is not recommended.

0.8.6

So that looks good! I will run a bigger program with the new code and see if anything changes.

[Marc Abramowitz (msabramo)]

Just tested out revision 4663 with py.test and some more involved code mocking sqlalchemy and it worked the same as before (which isn't actually working, but I think that's my fault, and the behavior didn't change so it's not working in the same exact way, which is what I think matters; i.e.: no regressions that I could detect).