1.7.0 breaks remote module execution

[alfredodeza]

The latest release (1.7.0) which includes the changes in this commit in particular: 544bcc8 is causing remote module execution to not work at all.

In gateway.py, this block:

        if isinstance(source, types.ModuleType):
            file_name = inspect.getsourcefile(source)
            if not file_name:
                source = inspect.getsource(source)
            else:
                source = None

Makes source always a None which is not correct. If/when commenting this source = None condition, a serialize error is raised:

  File "/tmp/bad/local/lib/python2.7/site-packages/execnet/gateway.py", line 135, in remote_exec
    gateway_base.dumps_internal((source, file_name, call_name, kwargs)))
  File "/tmp/bad/local/lib/python2.7/site-packages/execnet/gateway_base.py", line 1350, in dumps_internal
    return _Serializer().save(obj)
  File "/tmp/bad/local/lib/python2.7/site-packages/execnet/gateway_base.py", line 1368, in save
    self._save(obj)
  File "/tmp/bad/local/lib/python2.7/site-packages/execnet/gateway_base.py", line 1386, in _save
    dispatch(self, obj)
  File "/tmp/bad/local/lib/python2.7/site-packages/execnet/gateway_base.py", line 1471, in save_tuple
    self._save(item)
  File "/tmp/bad/local/lib/python2.7/site-packages/execnet/gateway_base.py", line 1384, in _save
    raise DumpError("can't serialize {}".format(tp))
execnet.gateway_base.DumpError: can't serialize <type 'module'>

I don't know what can I suggest here other than removing the optimization (as explained here 544bcc8#r310201906) since going back to 1.6 or anything previous to that commit, allows us to have a working application using remote modules

[nicoddemus]

@alfredodeza thanks a lot for the detailed diagnosis.

I'm fine with removing the optimization, I'm sure the gains are negligible (@joaoe do you agree)?

@alfredodeza would you like to open a PR? I would love to merge it and make a new release. 👍

[alfredodeza]

I am working on a PR. Thanks @nicoddemus for the quick action on this issue

[joaoe]

I'm fine with removing the optimization, I'm sure the gains are negligible (@joaoe do you agree)?

Yes, sure. It's really not worthwhile to add any complexity to that part of the code.

Might I also recommend that you add a test that ensure that execnet works when the source is not available remotely ? That would have saved a bug. :)

But replace the if/else with source = inspect.getsource(source)

[RonnyPfannschmidt]

this was closed by #109