Post-link scripts in a noarch package are not properly included

[kenodegard]

What happened?

When packaging a noarch package with post-link scripts only the post-link script cooresponding to the host machine is included in the output package and so in other words it isn't properly noarch.

The issue comes from how post-link (and pre-link and pre-unlink) scripts are detected:

conda-build/conda_build/build.py

Lines 154 to 178 in ca9de60

	def create_post_scripts(m: MetaData):
	"""
	Create scripts to run after build step
	"""
	ext = ".bat" if utils.on_win else ".sh"
	for tp in "pre-link", "post-link", "pre-unlink":
	# To have per-output link scripts they must be prefixed by the output name or be explicitly
	# specified in the build section
	is_output = "package:" not in m.get_recipe_text()
	scriptname = tp
	if is_output:
	scriptname = m.get_value(f"build/{tp}", f"{m.name()}-{tp}")
	scriptname += ext
	dst_name = f".{m.name()}-{tp}{ext}"
	src = join(m.path, scriptname)
	if isfile(src):
	dst_dir = join(
	m.config.host_prefix,
	"Scripts" if m.config.host_subdir.startswith("win-") else "bin",
	)
	if not isdir(dst_dir):
	os.makedirs(dst_dir, 0o775)
	dst = join(dst_dir, dst_name)
	utils.copy_into(src, dst, m.config.timeout, locking=m.config.locking)
	os.chmod(dst, 0o775)

Xref conda/conda#13389

[kenodegard]

pre-link, post-link, and pre-unlink are viewed as dangerous and legacy/deprecated, so we should look into removing it entirely

[kenodegard]

conda-forge forbids post-links for noarch: https://conda-forge.org/docs/maintainer/knowledge_base.html#noarch-python

to work around this, packages will have a multi-output recipe where the package itself would be noarch but the post-links are an arch specific package: https://github.com/conda-forge/bladerf-feedstock/blob/7deba2ef18fd1a9ba69239c61f018f67c24eba97/recipe/meta.yaml#L93

[mfansler]

Oh wow. Having an extra output seems like overkill if I just want to emit a message to users (i.e., echo into $PREFIX/.messages.txt). Is there any alternative means of doing this then going forward?

xref: conda-forge/r-tinytex-feedstock#53

Right now, thinking I'm just going to drop it.

[mfansler]

Hmm...but checking the info/files manifest does show bin/.r-tinytex-post-link.sh and the file is there. Still, seeing crashes on something as simple as echo "my message" >> .messages.txt.

[github-actions]

Hi there, thank you for your contribution!

This issue has been automatically marked as stale because it has not had recent activity. It will be closed automatically if no further activity occurs.

If you would like this issue to remain open please:

1. Verify that you can still reproduce the issue at hand
2. Comment that the issue is still reproducible and include:
   - What OS and version you reproduced the issue on
   - What steps you followed to reproduce the issue

NOTE: If this issue was closed prematurely, please leave a comment.

Thanks!

[beckermr]

We cannot remove these kinds of scripts and so this issue should be kept open only if there is still a bug. Otherwise it should be closed.