Test under python 3.12

[dairiki]

Python 3.12rc3 — the final release candidate — is out.

[dairiki]

See python/cpython#109590 for an explanation of the failure under python 3.12 on Windows.

This is happening during the package build stage, here

lektor/build_frontend.py

Lines 68 to 77 in efd15bc

	npm = shutil.which("npm")
	if npm is None:
	app.abort("npm is not available. can not build frontend")
	frontend = Path(root, FRONTEND)
	if not frontend.is_dir():
	app.abort("frontend source is missing. can not build frontend")
	app.display_info("npm install")
	subprocess.run((npm, "install"), cwd=frontend, check=True)

where shutil.which in python 3.12 finds a bash script for npm rather than the cmd string npm.cmd. (Windows doesn't know about bash scripts.)

Note that this (I think) only affects the package build process. In shouldn't affect users who install from PyPI.

I'm not sure what the best fix is. I guess wait to see what happens on python/cpython#109590 before worrying too much.

[dairiki]

See python/cpython#109590 for an explanation of the failure under python 3.12 on Windows.

So python/cpython#109590 was fixed in python/cpython#109995, however, that fix did not make it into python 3.12.0 ☹️ (It is, I think, scheduled for inclusion in 3.12.1.)

So here I've made things work by changing build_frontend.py to run npm using the shell=True argument to subprocess.run (instead of using shutil.which to resolve an absolute path to npm, which is broken on Windows in python 3.12.0 by python/cpython#109590).

The first workaround I tried, running npm without an absolute path, e.g. subprocess.run(("npm", "-v")) does not seem to work on Windows (⇒ FileNotFoundError for undetermined reasons).