pdm-without-use-uv

What it flags

Flags repositories and CI jobs that use PDM without use_uv = true configured.

PDM can delegate dependency resolution and installation to uv by setting one config flag. This speeds up pdm lock, pdm install, and pdm sync operations with no workflow changes.

Why it matters

PDM’s default backend uses pip’s resolver and installer, which can be slower than uv equivalents. Setting use_uv = true transparently swaps in uv for both resolution and installation, accelerating the most expensive parts of PDM’s workflow.

Current heuristic

The rule looks for:

• a repository with PDM configuration ([tool.pdm] in pyproject.toml or [pdm] in pdm.toml)
• absence of use_uv = true in the PDM config
• (workflow rule only) a CI job that runs pdm commands

The rule intentionally skips:

• repositories that already have use_uv = true configured
• jobs that do not run pdm commands
• repositories without visible PDM usage

When to ignore it

Ignore this finding when:

• the project relies on pip-specific behavior that uv’s resolver does not support
• the team has intentionally kept the pip backend for consistency
• the use_uv experimental flag causes issues with specific workflows

Suggested verification

• Run pdm lock and pdm install with and without use_uv = true
• Compare lock-resolution and installation wall-clock time
• Verify that the resulting lockfile and installed packages are equivalent

Sources

• https://pdm-project.org/latest/dev/experimental/#use-uv-as-the-backend
• https://docs.astral.sh/uv/guides/integration/