Support Python 3.7

[myint]

This fixes #271.

[serhiy-storchaka]

You can get better guess if inspect the maximal lineno of arguments, default values, annotations, etc. This could allow you to pass test_offsetWithMultiLineArgs in 3.7.

[myint]

Thanks for the suggestion!

[bitglue]

Please put this in your local git configuration, not pyflakes.

[bitglue]

Does this mean we can add 3.7 to travis.yml?

[bitglue]

Looks good, but if 3.7 works let's add it to travis.yml, provided travis supports such a thing.

[myint]

The closest thing to 3.7 is 3.7-dev. But our existing nightly already points to that.

https://docs.travis-ci.com/user/languages/python/

[methane]

We're thinking change again in 3.7b3. In this time, docstring will be moved from attribute to special AST node named DocString. See this example:

source = """\
def foo():
    "docstring"
"""

import ast
t = ast.parse(source)
print(ast.dump(t))

3.6: ... FunctionDef(name='foo', args=arguments(...), body=[Expr(value=Str(s='docstring'))], decorator_list=[], returns=None) ...

3.7b2: ... FunctionDef(name='foo', args=arguments(...), body=[], decorator_list=[], returns=None, docstring='docstring') ...

3.7b3?: ... FunctionDef(name='foo', args=arguments(args=[], vararg=None, kwonlyargs=[], kw_defaults=[], kwarg=None, defaults=[]), body=[DocString(s='docstring')], decorator_list=[], returns=None) ...

Of course, ast.getdocstring() works in all versions.
With this change, you can get lineno of docstring from the DocString node (while there is bug for now).

We want feedback from AST users. Please post your comment on this issue or Python-Dev mailing list.

[sigmavirus24]

@methane please also prod the code-quality@python.org mailing list, flake8-bugbear, and pydocstyle projects to get maximum exposure.

[methane]

Thanks for pointing them!

• Please give us feedback about AST change in Python 3.7 flake8-bugbear#34
• Please give us feedback about AST change in Python 3.7  pydocstyle#305