json.decoder.JSONDecodeError: Extra data: line 2 column 1 (char 3)

[maresb]

When running conda-lock in a GitHub action, you may see the following stack trace:

Traceback (most recent call last):
  File "/home/runner/work/conda-lock/conda-lock/conda_lock/conda_solver.py", line 388, in solve_specs_for_arch
    dryrun_install: DryRunInstall = json.loads(extract_json_object(proc.stdout))
  File "/opt/hostedtoolcache/Python/3.9.21/x64/lib/python3.9/json/__init__.py", line 346, in loads
    return _default_decoder.decode(s)
  File "/opt/hostedtoolcache/Python/3.9.21/x64/lib/python3.9/json/decoder.py", line 340, in decode
    raise JSONDecodeError("Extra data", s, end)
json.decoder.JSONDecodeError: Extra data: line 2 column 1 (char 3)

This is caused by an upstream issue in conda. To mitigate, see conda/conda#14569 (comment).

Another mitigation is to add the --micromamba flag with conda-lock in order to avoid the use of conda.

[basnijholt]

This issue happens for me using setup-micromamba so Conda is not even involved. Therefore I am not sure whether the explanation in conda/conda#14569 (comment) applies.

Perhaps it would be the ensure-conda that is used, which uses the broken conda version?

The --micromamba worked on CI but somehow didn't work locally.

[basnijholt]

FWIW, I was using

      - uses: mamba-org/setup-micromamba@v2
        with:
          environment-name: conda-lock-env
          create-args: unidep conda-lock conda-package-handling

which resulted in the error json.decoder.JSONDecodeError when running conda-lock (via unidep), after pinning micromamba and explicitly adding conda as a dependency, the error resolved.

Fixed:

      - uses: mamba-org/setup-micromamba@v2
        with:
          environment-name: conda-lock-env
          create-args: unidep conda-lock conda-package-handling conda
          micromamba-version: '1.5.12-0'