micromamba create not idempotent when envs_dirs does not exist

[maresb]

Troubleshooting docs

• My problem is not solved in the Troubleshooting docs

Anaconda default channels

• I do NOT use the Anaconda default channels (pkgs/* etc.)

How did you install Mamba?

Other (please describe)

Search tried in issue tracker

envs_dirs

Latest version of Mamba

• My problem is not solved with the latest version

Tried in Conda?

I do not have this problem with Conda, just with Mamba

Describe your issue

This issue seems to overlap with #3790. I have not checked if this is solved by either of the two PRs linked there.

To reproduce,

FROM mambaorg/micromamba:2.0.5

RUN cat <<EOF > explicit.txt
# Generated by conda-lock.
# platform: linux-64
# input_hash: ab45cd56a12b42dab7d2e540f01585dd1d1f8a7b51e43009d3475f75794137ad
@EXPLICIT
https://conda.anaconda.org/conda-forge/linux-64/_libgcc_mutex-0.1-conda_forge.tar.bz2#d7c89558ba9fa0495403155b64376d81
https://conda.anaconda.org/conda-forge/linux-64/libgomp-14.2.0-h77fa898_1.conda#cc3573974587f12dda90d96e3e55a702
https://conda.anaconda.org/conda-forge/linux-64/_openmp_mutex-4.5-2_gnu.tar.bz2#73aaf86a425cc6e73fcf236a5a46396d
https://conda.anaconda.org/conda-forge/linux-64/libgcc-14.2.0-h77fa898_1.conda#3cb76c3f10d3bc7f1105b2fc9db984df
https://conda.anaconda.org/conda-forge/linux-64/tzcode-2025a-hb9d3cd8_0.conda#e18bdeebf29176790089b654cfedaaec
EOF

RUN cat <<EOF > ~/.condarc
envs_dirs:
- ~/.conda
EOF

docker build . -t cl777-mm
docker run --rm -it cl777-mm
micromamba create --file explicit.txt --yes --name ficc
micromamba create --file explicit.txt --yes --name ficc

The first create command installs into the prefix $MAMBA_ROOT_PREFIX/envs/ficc = /opt/conda/envs/ficc.

The second (and any subsequent) create command installs into the envs_dirs prefix ~/.conda/ficc.

I expected this micromamba create command to be idempotent. After some investigation, I believe what's happening on the two successive micromamba create commands is:

1. a. Micromamba sees that ~/.conda from envs_dirs doesn't exist, so installs in $MAMBA_ROOT_PREFIX/envs/ficc = /opt/conda/envs/ficc.
   b. Micromamba creates ~/.conda/environments.txt.
2. Micromamba sees that ~/.conda now exists and installs in the prefix ~/.conda/ficc.

mamba info / micromamba info

~/.condarc

envs_dirs:
- ~/.conda

[jjerphan]

#3796 likely fixes it.