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New incremental mode (-i) crasher #3232
Description
I've seen this a few times myself and now it's being reported. The traceback ends with
File "/Users/x/src/server/.mypy/venv/lib/python3.6/site-packages/mypy/types.py", line 388, in accept
return visitor.visit_instance(self)
File "/Users/x/src/server/.mypy/venv/lib/python3.6/site-packages/mypy/fixup.py", line 153, in visit_instance
node = lookup_qualified(self.modules, type_ref, self.quick_and_dirty)
File "/Users/x/src/server/.mypy/venv/lib/python3.6/site-packages/mypy/fixup.py", line 237, in lookup_qualified
stnode = lookup_qualified_stnode(modules, name, quick_and_dirty)
File "/Users/x/src/server/.mypy/venv/lib/python3.6/site-packages/mypy/fixup.py", line 252, in lookup_qualified_stnode
assert '.' in head, "Cannot find %s" % (name,)
AssertionError: Cannot find _importlib_modulespec.ModuleType
Activity
ilevkivskyi commentedon Apr 24, 2017
Probably this is a "leftover" that is still not fixed by #3203
@pkch Could you please take a look?
gvanrossum commentedon Apr 24, 2017
Oh, I'll also check if the user who reported this had a sufficiently recent mypy version.
gvanrossum commentedon Apr 24, 2017
The user who reported this was running an older version of mypy, so there's nothing to see and nothing to do here.[UPDATE: I was wrong there]
pkch commentedon Apr 24, 2017
Unfortunately, this is the recent version (after my fix). I can see from the line numbers. Is there any information about the crash (command line, whether it's intermittent, warm/cold cache, etc)?
gvanrossum commentedon Apr 24, 2017
Well, actually the user reported they got the crash after upgrading to mypy 1d1c62d (and they have the Terminal window logs to prove it to me :-) so I'm afraid I need to reopen this. Sorry for the quick cycling.
gvanrossum commentedon Apr 24, 2017
The user also reported: It [mypy -i] worked the first two times, then he added
# type: ignoreto the (previously empty)__init__.pyof a very commonly used toplevel package, then it crashed.gvanrossum commentedon Apr 24, 2017
Maybe also important, we have a script that computes the list of files to pass to mypy, and the offending
__init__.pyfile (let's call itdropbox/__init__.py) was previously empty, so the result of adding# type: ignoreto it was to include it in the command line. Many submodules ofdropboxdo have type annotations and are included in both runs.Also, we run with
--follow-imports=skip --ignore-missing-imports. This implies that thedropbox.__init__.pyfile was not analyzed in any way in the runs before the crash, but it was analyzed in the crashing run.gvanrossum commentedon Apr 24, 2017
Also important: Python 2 mode!
ilevkivskyi commentedon Apr 24, 2017
This is the key I think.
ilevkivskyi commentedon Apr 24, 2017
@pkch maybe the solution is just to skip the reverse renaming in the PY2 mode?
pkch commentedon Apr 24, 2017
Yup, python 2 doesn't use
_importlib_modulespecat all.gvanrossum commentedon Apr 24, 2017
Do you have time to make a fix?
pkch commentedon Apr 24, 2017
Yes. I can't reproduce the crash, but I'm pretty sure what @ilevkivskyi said is sufficient. If it still crashes, we'll just have to look further.
gvanrossum commentedon Apr 24, 2017
Please send a PR -- I have a repro but I can't publish it, so I'll test your PR against it once I have it.
pkch commentedon Apr 24, 2017
I used the simplest fix I could (just check that
_importlib_modulespecexists before redirecting). But I guess it's fine, since this is a very low-level implementation detail.