Re: [PATCH 4/5] python: add .gitignore

From: John Snow <jsnow@redhat.com>
To: Markus Armbruster <armbru@redhat.com>, Thomas Huth <thuth@redhat.com>
Cc: "Fam Zheng" <fam@euphon.net>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Daniel P.Berrangé" <berrange@redhat.com>,
	"Eduardo Habkost" <ehabkost@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@redhat.com>,
	qemu-devel@nongnu.org,
	"Wainer dos Santos Moschetta" <wainersm@redhat.com>,
	"Cleber Rosa" <crosa@redhat.com>,
	"Alex Bennée" <alex.bennee@linaro.org>
Subject: Re: [PATCH 4/5] python: add .gitignore
Date: Wed, 28 Oct 2020 09:39:07 -0400	[thread overview]
Message-ID: <3c86b845-31ad-0956-d095-6a6323679a90@redhat.com> (raw)
In-Reply-To: <871rhi1zim.fsf@dusky.pond.sub.org>

On 10/28/20 5:16 AM, Markus Armbruster wrote:
> Thomas Huth <thuth@redhat.com> writes:
> 
>> On 27/10/2020 23.38, John Snow wrote:
>>> Ignore build and package output (build, dist, qemu.egg-info);
>>> effectively these are "in-tree" builds of a kind.
>>
>> Since we recently moved away from in-tree builds, could these also be made
>> out-of-tree only?
> 
> The build should only write to the per-build spaces: the build tree,
> per-build scratch in /tmp, ...  Writing to shared space such as the
> source tree can break parallel independent builds.  I consider that a
> bug.
> 

It's not really a "build" in that traditional sense, but if you were to 
execute "make venv-check" in parallel, I'm not confident it would work 
right. Don't do that, I guess.

This has nothing to do with QEMU's build step. We don't need to "build" 
or "install" this package to use it during QEMU builds or (most) 
testing. We *do* need to install it to a virtual environment to test it 
with an explicit set of linter packages, though.

See also: why do we ignore *.pyc and __pycache__ files in the whole 
tree? These are in effect build artifacts too. I'm not sure I would know 
how to avoid those being created. Maybe it's possible? but... I don't 
think this is a problem that we have to solve, actually.

OK, all that whining aside, I will give it a legitimate try. I just 
wanted to prepare you for disappointment. I might be able to move build/ 
and dist/, but I have doubts that anything can reasonably be done about 
qemu.egg-info, __pycache__, .mypy_cache, or the like.

--js