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Thu, 17 Sep 2020 09:46:29 +0200 (CEST) From: Markus Armbruster To: John Snow Subject: Re: [PATCH 04/37] qapi: move generator entrypoint into module References: <20200915224027.2529813-1-jsnow@redhat.com> <20200915224027.2529813-5-jsnow@redhat.com> <877dsuos1n.fsf@dusky.pond.sub.org> <5b42ff66-9bc3-ea2e-a3f7-5105628e2c43@redhat.com> Date: Thu, 17 Sep 2020 09:46:29 +0200 In-Reply-To: <5b42ff66-9bc3-ea2e-a3f7-5105628e2c43@redhat.com> (John Snow's message of "Wed, 16 Sep 2020 10:24:03 -0400") Message-ID: <87ft7gg816.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Content-Type: text/plain Received-SPF: pass client-ip=63.128.21.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/16 20:51:18 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -50 X-Spam_score: -5.1 X-Spam_bar: ----- X-Spam_report: (-5.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.999, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Alex =?utf-8?Q?Benn=C3=A9e?= , qemu-devel@nongnu.org, Eduardo Habkost , Cleber Rosa Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" John Snow writes: > On 9/16/20 7:54 AM, Markus Armbruster wrote: >> John Snow writes: >> >>> As part of delinting and adding type hints to the QAPI generator, it's >>> helpful for the entrypoint to be part of the module, only leaving a very >>> tiny entrypoint shim outside of the module. >>> >>> As a result, all of the include statements are reworked to be module-aware, >>> as explicit relative imports. >> Should this be split into two commits, one for each of the >> paragraphs >> above? >> > > Hmm ... I hadn't considered it was possible, but actually ... I guess > I can split those out, yeah. > >> PEP 8 recommends absolute imports, with one exception: >> However, explicit relative imports are an acceptable >> alternative to >> absolute imports, especially when dealing with complex package >> layouts where using absolute imports would be unnecessarily verbose: >> from . import sibling >> from .sibling import example >> Standard library code should avoid complex package layouts and >> always use absolute imports. >> Do you think it covers your use of relative imports? >> > > Admittedly I am going by trial and error; my experience is that the > relative imports behave the nicest. > > There is a historical fear of explicit relative imports because they > are "new" and years of Python2 compatibility Having to struggle with that for years was bound to damage brains. > rendered many afraid of > them. It is advice safely ignored in my opinion. > > Using absolute imports (e.g. from qapi.sibling import foo) gets messy > in virtual environments when you have *installed* the module in > question: it becomes ambiguous as to *which* qapi you meant: the one > in this folder, or the one installed to the environment? > > Python, mypy, pylint, flake8 etc disagree sometimes, or can get > confused; thinking there are two copies of each module. > > Just my experience that relative imports seem to give me the least trouble. > >>> This is done primarily for the benefit of python tooling (pylint, mypy, >>> flake8, et al) which otherwise has trouble consistently resolving >>> "qapi.x" to mean "a sibling file in this folder." >> Can you give me an example of some tool having troube? >> > > I'd have to code up some examples. I have some hobby code unrelated to > QEMU where I struggled to get flake8, mypy, and pylint all cooperating > with an import regime until I gave up and used explicit relative imports. I'd make the switch when we actually do run into trouble. But I'm willing to take your advice and switch now. [...]