Regression: Docs no longer build with py27-sphinx since #2394

[zmwangx]

Docs used to build just fine with Sphinx under Python 2.7. #2394 introduced an import mypy.git to mypy.version (which is imported by Sphinx's conf.py), and since mypy.git contains function annotations not supported by Python 2.7, trying to build the docs with py27-sphinx now causes an error:

$ make html
sphinx-build -b html -d build/doctrees   source build/html
Running Sphinx v1.5.1

Configuration error:
There is a syntax error in your configuration file: invalid syntax (git.py, line 10)
make: *** [html] Error 1

This unfortunately is causing some trouble for Homebrew (see Homebrew/homebrew-core#7143), since our sphinx-doc formula is py27 only at the moment.

We'll of course try to fix this on Homebrew's side, but maybe py27-sphinx compatibility could be restored? One solution I can think of is to add something like mypy/version_static.py with the plain old version declaration:

__version__ = '0.4.7-dev'

then import mypy.version_static in docs/source/conf.py instead. The downside is it needs to be bumped alongside version.py at the same time, and when building from a git tree, the commit hash won't be included in the docs.

[ambv]

I personally like what Pallets' projects are doing: AST analyzing the version string, without really importing it, like: https://github.com/pallets/click/blob/master/setup.py#L11.

We'd need typed-ast instead to be able to generate the AST on Python 2 as well and we should be all set. Let me see how much work it is to prepare a PR for this.

[ambv]

Turns out we don't even need typed-ast if we only evaluate the string found in the version assignment.

[gvanrossum]

While I'm not sure I care about Sphinx-2.7 given that mypy solidly requires Python 3 to run, the hackery in version.py is definitely not ideal (and may even have some broken edge cases, search the tracker). But I'm not sure that just opening the file instead of importing it is really better (the import machinery is *sooo* much subtler than that...).

…

On Tue, Dec 20, 2016 at 1:25 PM, Łukasz Langa ***@***.***> wrote: Turns out we don't even need typed-ast if we only evaluate the string found in the *version* assignment. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#2593 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACwrMuO3ExBaihFdYdg4VY9wIsR7mjD6ks5rKEfVgaJpZM4LSSab> .

-- --Guido van Rossum (python.org/~guido)

[gvanrossum]

@ambv Since you closed your PR, did you intend this issue to be closed with "won't fix" as well?

[zmwangx]

As the OP I'm okay with wont fix. I've patched the Homebrew formula (with the version_static hack mentioned above, only at build time) and no one's mad at me so far.

[ambv]

@ambv GitHub closed it since I mistakenly put it on master in my fork :)

But yeah, if wontfix is okay for @zmwangx, it's better for us to keep things simple.