gh-122661: Remove GNU make-specific directive from Doc/Makefile

[bibajz]

Description

define - https://www.gnu.org/software/make/manual/html_node/Multi_002dLine.html - is a GNU make extension not generally supported by other makes.

Changes

Introduce UV variable to accomodate for the case when uv is not in PATH.

Remove the

$ python -m $(1) --version >/dev/null

commands that can prevent the installation of a package when it's already present.

The rationale is this approach is really fragile, for multiple reasons.

Firstly, it works on packages defining __main__.py module, there- fore as an example, anyio==4.4.0 package, even if installed, would output:

$ /tmp/venv/bin/python -m anyio >/dev/null /tmp/venv/bin/python: No module named anyio.__main__;'anyio' is a package and cannot be directly executed $ echo$? 1

Secondly, unlike package installation, which is insensitive to capitalization as well as -/_ separators - https://packaging.python.org/en/latest/specifications/name-normalization/#names-and-normalization - module names are sensitive to naming, meaning this may happen (and indeed happened in bc37ac7)

$ /tmp/venv/bin/python -m sphinx-autobuild --help >/dev/null /tmp/venv/bin/python: No module named sphinx-autobuild $ echo$? 1 $ /tmp/venv/bin/python -m sphinx_autobuild --help >/dev/null $ echo$? 0

And lastly, name of the package may not be the same as its contents that are subsequently imported. Consider PyYAML==6.0.1, whose contents are importable from the yaml namespace - https://pyyaml.org/wiki/PyYAMLDocumentation

$ /tmp/venv/bin/python -m pyyaml >/dev/null /tmp/venv/bin/python: No module named pyyaml $ /tmp/venv/bin/python -m yaml >/dev/null /tmp/venv/bin/python: No module named yaml.__main__;'yaml' is a package and cannot be directly executed

Further work

The whole Makefile does not work properly when not using GNU make. Consider the following target:

.PHONY: html html: BUILDER = html html: build @echo "Build finished. The HTML pages are in build/html." 

the way BUILDER variable is set, in a prerequisite, does not work in other makes - variable is empty when defined this way. This will probably need another issue and pull request.

• Issue: make distclean needs GNU make to work #122661

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📚 Documentation preview 📚: https://cpython-previews--122662.org.readthedocs.build/

[ghost]

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[bedevere-app]

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If this change has little impact on Python users, wait for a maintainer to apply the skip news label instead.

[bibajz]

As alluded in the PR description, this code contains a bug, because the python -m sphinx-autobuild always fails:

$ /tmp/venv/bin/python -m sphinx-autobuild --help >/dev/null /tmp/venv/bin/python: No module named sphinx-autobuild $ echo $? 1 $ /tmp/venv/bin/python -m sphinx_autobuild --help >/dev/null $ echo $? 0 

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@hugovk

[hugovk]

Just to let you know, there have been discussions about requiring GNU make, but no decisions have been made yet:

https://discuss.python.org/t/make-compatibility-requirements/26869

Anyway, these changes are fine and thanks for the fixes!

[miss-islington-app]

Thanks @bibajz for the PR, and @hugovk for merging it 🌮🎉.. I'm working now to backport this PR to: 3.12, 3.13.
🐍🍒⛏🤖

[bedevere-app]

GH-122668 is a backport of this pull request to the 3.13 branch.

[bedevere-app]

GH-122669 is a backport of this pull request to the 3.12 branch.

[bibajz]

Just to let you know, there have been discussions about requiring GNU make, but no decisions have been made yet:

https://discuss.python.org/t/make-compatibility-requirements/26869

Anyway, these changes are fine and thanks for the fixes!

Thank you for the pointer to the forum thread.

As I pointed out in the Further work section, the whole Doc/Makefile implicitly assumes GNU make - the syntax of variable setting as a prerequisite is GNU make-specific. Otherwise, my changes could be

.PHONY: _ensure-sphinx-autobuild _ensure-sphinx-autobuild: PACKAGE=sphinx-autobuild _ensure-sphinx-autobuild: _ensure-package 

instead of

.PHONY: _ensure-sphinx-autobuild _ensure-sphinx-autobuild: make _ensure-package PACKAGE=sphinx-autobuild 

which would be IMO nicer, since you can see the prerequisite of _ensure-sphinx-autobuild right away.

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Personally, I do not have a horse in this race, be it GNU make or BSD make, but it would be nice to reach an explicit resolution which one is actually necessary to build stuff correctly.

Running the targets on FreeBSD with gmake worked even before my patch.

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One last thing - I wanted to ask about commit messages.

In my original commit, I wrote a really detailed message what changes (and why) are introduced - 06b20b5 .

However, on main, there is only the merge commit - f5c39b3 - with links to GitHub issue and pull request.

Why can't the commit messages be included as well? This forces CPython to rely on out-of-band information, namely a git provider, which may or may not be present in years to come...

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Thank you for your time and answers! (If anyone is more knowledgeable about the commit messages being off-loaded, please, tag them here, I find commit messages a treasure trove of information and oftentimes joy to read 😉 )

@hugovk

[hugovk]

I think the commit message body was cleared by the Refined GitHub browser extension I have installed. If there are many commits, the default would be to list all the commit titles only, which is less useful. I can see it can be less useful when there's a single commit with a detailed body.

[faulhaberben]

Sorry, I have a side question here: Will you close the issue manually @bibajz or is that taken care of by a bot? @hugovk

#122661 (comment)

[hugovk]

It needs to be done manually, I'll do it. Thanks for the reminder!