Re: [PATCH] tests: add a "check-flake8" test for validating python code style

[Paolo Bonzini <pbonzini@redhat.com>]

On 29/04/20 17:36, Daniel P. Berrangé wrote:
> The flake8 program is a standard tool used by Python projects for
> validating many commonly recommended style rules. It would be desirable
> for QEMU to come into alignment with normal Python coding style best
> practices.
> 
> QEMU currently violates a huge number of the style rules, so we can't
> blindly turn it on. Instead this patch introduces use of flake8 with
> a huge ignore list to turn off everything that is currently violated.
> 
> The following descriptions are mostly taken from:
> 
>   https://www.flake8rules.com/

I suggest instead using "black" and just reformat everything in a huge
patch; that's what we're using for Patchew.

It's not perfect, and especially one needs to get used to the double
quotes instead of single quotes for strings.  However overall it is
pretty good, and I've never seen it do something clearly "wrong".

> On its own this patch doesn't really do much of use except try to stop the
> situation getting worse. To be valuable some motivated contributor(s)
> would need to go through fixing the code, and re-enabling each excluded
> warning category one at a time.
> 
> I'm mostly proposing this patch as a starting point for discussion, to
> see if anyone is indeed motivated to take on the code cleanup challenge,
> and feed the fixes in through the various maintainers trees.

If we go with "black" I suggest just doing a big patch for everything,
since it's easy for maintainers to rebase by running black at each step.
 Overall our usage of Python is small enough that it should not be a big
deal.

Paolo