[conda] trouble when installing conda-build into an environment

[Paul Madden]

I had until recently been extracting metadata from meta.yaml (for various
purposes, e.g. to get the package version to create a git tag) just using
standard YAML processing in Python. However, when jinja2 syntax is used in
meta.yaml, it's no longer valid YAML, so I took Mike Sarahan's advice and
switched to using conda_build.api.render() to fully render meta.yaml and
then query the returned object for the information I need. This is quite
nice, but I ran into two problems:

1. Rendering meta.yaml this way produces some informational messages on
stdout that I don't want to see in my use case, and also results in a build
directory being created under conda-bld, that conda build later informs you
that you can/should clean up with "conda build purge". If I do a lot of
renders of meta.yaml in my workflow, these can really pile up. I solved
these problems by setting the kwargs verbose=False (to eliminate the
informational message) croot=tmpdir (to have the render performed in a
Python-created temporary directory, that I then cleaned up). I'm just
sharing this in case it's useful to anyone.

2. Then this happened (simplified version here for demo purposes):

~ % conda create -c defaults --override-channels -y -n foo conda-build
[...]
~ % source activate foo
(foo) ~ % conda info -e
# conda environments:
#
base /lscratch/pmadden/miniconda
foo * /lscratch/pmadden/miniconda/envs/foo


(foo) ~ % source deactivate foo
~ % conda info -e
# conda environments:
#
/lscratch/pmadden/miniconda
base * /lscratch/pmadden/miniconda/envs/foo


~ % conda env remove -y -n foo


EnvironmentLocationNotFound: Not a conda environment: /lscratch/pmadden/
miniconda/envs/foo/envs/foo

Is that expected? Should I not be able to install conda-build in an
environment? Since it's apparently the only reliable way to interpret
meta.yaml, it would be useful to be able to do so. Otherwise, I can't
immediately think of anything better than deriving meta.yaml from some
other data structure that can be reliably parsed by external tooling, but
that would be an unfortunate complication.

paul

[Paul Madden]

It seems I can avoid issue 2, at least in the simple case above, by doing
using "conda [de]activate" instead of "source [de]activate". Definitely
will do that for now, but am still curious if the behavior using "source"
is expected.