Cannot find exec_module for _importlib_modulespec.exec_module with incremental

[refi64]

Still trying to get a test case, but here's the traceback:

ryan@DevPC-LX ~/blaze-py master $ mypy blaze
Traceback (most recent call last):
  File "/media/ryan/stuff/anaconda/bin/mypy", line 6, in <module>
    exec(compile(open(__file__).read(), __file__, 'exec'))
  File "/media/ryan/stuff/mypy/scripts/mypy", line 6, in <module>
    main(__file__)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/main.py", line 41, in main
    res = type_check_only(sources, bin_dir, options)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/main.py", line 86, in type_check_only
    options=options)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/build.py", line 183, in build
    dispatch(sources, manager)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/build.py", line 1512, in dispatch
    process_graph(graph, manager)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/build.py", line 1685, in process_graph
    process_fresh_scc(graph, prev_scc)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/build.py", line 1754, in process_fresh_scc
    graph[id].fix_cross_refs()
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/build.py", line 1300, in fix_cross_refs
    fixup_module_pass_one(self.tree, self.manager.modules)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/fixup.py", line 17, in fixup_module_pass_one
    node_fixer.visit_symbol_table(tree.names)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/fixup.py", line 82, in visit_symbol_table
    self.visit_type_info(value.node)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/fixup.py", line 51, in visit_type_info
    self.visit_symbol_table(info.names)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/fixup.py", line 75, in visit_symbol_table
    stnode = lookup_qualified_stnode(self.modules, cross_ref)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/fixup.py", line 244, in lookup_qualified_stnode
    assert key in names, "Cannot find %s for %s" % (key, name)
AssertionError: Cannot find exec_module for _importlib_modulespec.exec_module
ryan@DevPC-LX ~/blaze-py master $ 

[refi64]

Test case:

class A: pass
class B: pass
class C: pass

class X:
    attr: A
class Y:
    attr: B
class Z(X, Y):
    attr: C

Example:

ryan@DevPC-LX ~/blaze-mypy2 master $ mypy --fast-parser --python-version 3.6 -i x.py
x.py: note: In class "Z":
x.py:9: error: Definition of "attr" in base class "X" is incompatible with definition in base class "Y"
ryan@DevPC-LX ~/blaze-mypy2 master $ mypy --fast-parser --python-version 3.6 -i x.py
Traceback (most recent call last):
  File "/media/ryan/stuff/anaconda/bin/mypy", line 6, in <module>
    exec(compile(open(__file__).read(), __file__, 'exec'))
  File "/media/ryan/stuff/mypy/scripts/mypy", line 6, in <module>
    main(__file__)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/main.py", line 41, in main
    res = type_check_only(sources, bin_dir, options)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/main.py", line 86, in type_check_only
    options=options)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/build.py", line 183, in build
    dispatch(sources, manager)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/build.py", line 1512, in dispatch
    process_graph(graph, manager)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/build.py", line 1685, in process_graph
    process_fresh_scc(graph, prev_scc)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/build.py", line 1754, in process_fresh_scc
    graph[id].fix_cross_refs()
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/build.py", line 1300, in fix_cross_refs
    fixup_module_pass_one(self.tree, self.manager.modules)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/fixup.py", line 17, in fixup_module_pass_one
    node_fixer.visit_symbol_table(tree.names)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/fixup.py", line 82, in visit_symbol_table
    self.visit_type_info(value.node)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/fixup.py", line 51, in visit_type_info
    self.visit_symbol_table(info.names)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/fixup.py", line 75, in visit_symbol_table
    stnode = lookup_qualified_stnode(self.modules, cross_ref)
  File "/media/stuff/anaconda/lib/python3.4/site-packages/mypy/fixup.py", line 244, in lookup_qualified_stnode
    assert key in names, "Cannot find %s for %s" % (key, name)
AssertionError: Cannot find module_repr for _importlib_modulespec.module_repr
ryan@DevPC-LX ~/blaze-mypy2 master $ 

[gvanrossum]

Looks like this is new since 0.4.5. Perhaps you can bisect?

[refi64]

@gvanrossum First bad commit was 075a8da, from #2304.

[refi64]

Also, here's a slightly smaller test case:

class A: pass
class B: pass

class X:
    attr: A
class Y:
    attr: B
class Z(X, Y): pass

The core bug seems to be when two different base classes define an attribute to be of different types.

[refi64]

I've been doing some research. This apparently has something to do with functions defined inside of conditionals inside classes, like:

class X:
    if sys.version_info >= (1, 2, 3):
        def f(self): pass
    else:
        def f(self): pass

Previously, only global functions went through the first pass of semantic analysis. Now, because of the changes in #2304, methods are also analyzed. Immediately returning from FirstPass.visit_if_stmt will work around the issue.

[refi64]

AAAAND THE BUG IS...this innocent line:

         func._fullname = sem.qualified_name(func.name())

Now methods are being evaluated, BUT qualified_name always returns a module-level name. Kind of anti-climatic...