python setup.py install doesn't work from github tarballs

[sbailey]

python setup.py install doesn't work from github tarballs, giving the following message:

The requested path 'astropy_helpers' for importing astropy_helpers does not exist, or does not contain a copy of the astropy_helpers package.
Downloading 'astropy-helpers'; run setup.py with the --offline option to force offline installation.
No source found for the 'astropy_helpers' package; astropy_helpers must be available and importable as a prerequisite to building or installing this package.

If the problem persists consider installing astropy_helpers manually using pip
(`pip install astropy_helpers`) or by manually downloading the source archive,
extracting it, and installing by running `python setup.py install` from the
root of the extracted source code.

When running from a git clone, it is able to automatically download astropy_helpers and install specsim without doing a global installation of astropy_helpers. It would be helpful if that would also work for the github tarballs.

In the meantime we've been doing "by-hand" installs from git clones at NERSC.

[dkirkby]

I cannot reproduce this in a clean conda env, using:

curl -O https://codeload.github.com/desihub/specsim/tar.gz/v0.12
tar -ztf v0.12
cd specsim-0.12
conda create -n specsim_test
conda activate specsim_test
python setup.py install

The install command runs normally with output that starts with:

The requested path 'astropy_helpers' for importing astropy_helpers does not exist, or does not contain a copy of the astropy_helpers package.
Downloading 'astropy-helpers'; run setup.py with the --offline option to force offline installation.
Freezing version number to ./specsim/version.py
running install
...

I'm not sure why you are getting this error, but it seems to be related to your (nersc?) environment:

No source found for the 'astropy_helpers' package; astropy_helpers must be available and importable as a prerequisite to building or installing this package.

Note that if I replace python setup.py install with pip install ., the install appears to succeed without ever downloading astropy_helpers.

[weaverba137]

Another thing to keep in mind is that desiInstall interprets anything written to stderr as an error message, even if the message is actually just a warning or informational.

[sbailey]

I have the same problem on my laptop, including the version you lists above with the conda environment. i.e. it isn't specific to NERSC or desiInstall. pip install . also fails for me.

@dkirkby do you possibly have astropy_helpers pre-installed in your path somewhere else such that the install fails to grab it but it can proceed anyway?

Note that there is a typo in your commands tar -ztf v0.12 -> tar -zxf v0.12. Is it possible that you didn't really run this in the extracted tarball that you just downloaded?