Detecting unassigned triple quoted strings

[unode]

Python doesn't provide a way to do block quotes other than prefixing all lines in a block with # . Some people find this "too complicated" and have started to use triple quotes (""" or ''') to achieve a block quote like behavior.

Although not explicitly stated in PEP8, this is considered by many bad practice and in some occasions confusion about how docstrings work.

In light of this, I propose that triple quotes that are not docstrings, are not assigned to variables, nor contained in (), [] or {}, are treated as errors or raise a warning.

[myint]

I'd like something like this, but it seems like something that should be added to pylint.

[florentx]

They are not discouraged by the official PEP.

You have mention of them in PEP 257 where they just say they are allowed. http://www.python.org/dev/peps/pep-0257/#what-is-a-docstring

However I agree with you it's not something I recommend.

I close this issue, probably it will fit better in a larger tool like pylint. If someone contributes a simple checker for this, we might consider merging it in the library (and putting it in the DEFAULT_IGNORE list).

[unode]

I would say that PEPs have never touched the subject outside its use for docstrings. I haven't read anywhere in a PEP that you "can use triple quote for block commenting" nor that you shouldn't.

I'll consider transferring the request to pylint and pyflakes. Thanks

[florentx]

If you follow the link I posted above, you might read that:

String literals occurring elsewhere in Python code may also act as documentation. They are not recognized by the Python bytecode compiler and are not accessible as runtime object attributes (i.e. not assigned to __doc__) ...

This is the thing I was referring to.

[myint]

It turns out that pylint already supports this.

"""Real docstring"""

def testing():
    """Real docstring"""
    """
    "commented" out stuff
    x = 1
    """

    """More
    commented
    out stuff."""

$ pylint --report=no  blah.py 
************* Module blah
W:  8,-1:testing: String statement has no effect
W: 12,-1:testing: String statement has no effect

[unode]

That's neat, I didn't know that. Thanks for the info.

[sigmavirus24]

syntastic(vim) + pyflakes will catch it too. I would expect that syntastic + pylint would too. And I agree with @florentx, that it shouldn't raise an error but I think pyflakes/pylint were just designed for PEP8 compliance but also for improving performance by cleaning up unnecessary items, e.g., unused imports, unused variable declarations, etc.

Edit see my comment below Unode's. virtualenv tricked me.

[unode]

@sigmavirus24 Which version of pyflakes are you using? I've started using flake8 recently and at least on pyflakes 0.5.0 it doesn't complain.

[sigmavirus24]

@Unode seems that syntastic saw pylint first since I was using virtualenv, I was mistaken about that. Sorry for the confusion.