false redefined-outer-name when using del

[vapier]

simple test code:

path = __file__
del path
def some_func_of_mine(path):
    print(path)

testing pylint-1.5.4 shows:

$ pylint test.py
W:  3,22: Redefining name 'path' from outer scope (line 1) (redefined-outer-name)

[PCManticore]

We don't understand deletions of values yet.

[dumblob]

This would be great addition. It's one of the most frequent errors we always get.

I didn't look at the internals, but would it make sense to look at how mypy solves this (mypy understands del statements and does not produce any false positivess)?

[clavedeluna]

I'm looking at how to approach this. this is the code near where "redefined-outer-name" is about to be emitted.

In the orig example in this issue

path = __file__
del path
def some_func_of_mine(path):
    print(path)

globs is

(Pdb) globs
{'path': [<AssignName.path l.1 at 0x10ad69f40>, <DelName.path l.2 at 0x10ade0070>], 'some_func_of_mine': [<FunctionDef.some_func_of_mine l.3 at 0x10ade0040>]}

Seems like we could use this information, particularly the fact that DelName.path exists, and short-circuit so that Redefining name 'path' from outer scope (line 1) (redefined-outer-name) isn't part of the output.

Thoughts?

[Pierre-Sassoulas]

This seems dependent on #4795, doing it in each possible checker will be very hard to maintain and do right.

[clavedeluna]

This seems dependent on #4795, doing it in each possible checker will be very hard to maintain and do right.

Sounds good. Then the minor label isn't applicable, correct?

[Pierre-Sassoulas]

minor means "polishing" i.e. low priority, not "easy to do " :)