Support conda repoquery depends for package dependency graph

[ktaletsk]

Summary

The package dependency graph feature currently requires mamba because it uses mamba repoquery depends --json <pkg>. However, recent versions of conda with conda-libmamba-solver now support the same repoquery depends command.

Background Research

Current Implementation

The pkg_depends method in envmanager.py previously checked is_mamba() and returned early if conda was detected:

if not self.is_mamba():
    self.log.warning(
        "Package manager '{}' does not support dependency query.".format(
            self.manager
        )
    )
    return {pkg: None}

Discovery: conda-libmamba-solver provides repoquery

According to the conda 25.x documentation:

Note: The conda repoquery depends command is provided by the conda-libmamba-solver.

This means users with conda-libmamba-solver installed can use:

conda repoquery depends --json <package>

The JSON output format is identical to mamba's output, making it a drop-in replacement.

Preliminary Fix (Tested Successfully)

We temporarily removed the is_mamba() check, allowing both mamba and conda to use repoquery depends. This was tested successfully in an environment with:

• conda 24.11.3
• conda-libmamba-solver installed

Both the package dependency graph visualization and environment listing work correctly.

Proposed Implementation

Option 1: Simple removal of mamba check (current temporary fix)

• Pros: Simple, works for users with libmamba-solver
• Cons: Will fail for users without libmamba-solver

Option 2: Try/catch with graceful fallback

async def pkg_depends(self, pkg: str) -> Dict[str, List[str]]:
    try:
        ans = await self._execute(self.manager, "repoquery", "depends", "--json", pkg)
        # ... process response
    except Exception:
        self.log.warning("repoquery not available. Install mamba or conda-libmamba-solver.")
        return {pkg: None}

Option 3: Explicit detection of repoquery support

• Run conda repoquery --help or similar to detect availability
• Cache the result like we do for manager detection

Tasks

• Decide on implementation approach
• Add proper error handling for environments without repoquery support
• Update user-facing error message in PkgGraph.tsx to mention conda-libmamba-solver as alternative to mamba
• Add tests for conda repoquery path
• Update documentation

Related Files

• mamba_gator/envmanager.py - pkg_depends() method
• packages/common/src/components/PkgGraph.tsx - Frontend error message

References

• conda repoquery depends documentation
• conda-libmamba-solver