CI and pre-commit

In a pipeline

- name: Run quality checks
  run: mix quality

That is the whole integration. The run exits non-zero if any stage failed, and prints detail only for the stages that did.

To have the pipeline act on the result rather than just fail, write a report alongside the human output and read it in a later step:

- name: Run quality checks
  run: mix quality --report quality.json

- name: Upload report
  if: always()
  uses: actions/upload-artifact@v4
  with:
    name: quality-report
    path: quality.json

See reports.md for the schema.

Warming the Dialyzer PLT

Dialyzer analyses against a PLT, a cache of every module it has already seen. Building one takes minutes; analysing against a warm one takes seconds. On a fresh container that cost lands inside a check whose only output is one line at the end, so the job looks hung.

mix quality.plt is the warm-up target. It is the same work mix quality would otherwise do, moved somewhere it can be cached:

- name: Restore PLT cache
  uses: actions/cache@v4
  with:
    path: |
      _build
      ~/.mix
    key: ${{ runner.os }}-plt-${{ hashFiles('**/mix.lock') }}

- name: Build PLT
  run: mix quality.plt

- name: Run quality checks
  run: mix quality

Cache both _build and ~/.mix: dialyxir keeps the core PLTs in the Mix home and the project's own under _build.

Unlike a check, this task's whole point is the progress, so dialyxir's output is passed through as it arrives rather than summarised.

Skipping the warm-up breaks nothing. The run builds the PLT itself, says so while it happens, and reports it afterwards:

⋯ Dialyzer: building PLT (this is a one-time cost)
✓ Dialyzer: No warnings (PLT built this run) (252.4s)

That is a normal pass: the analysis is as trustworthy as any other.

mix quality.plt requires :dialyxir. A project without it has no PLT to build, and the task says so rather than doing nothing quietly.

In a container image

Same idea, one layer earlier. Run it after mix deps.get and before any check, so the PLT is baked into the image instead of built on every run:

RUN mix deps.get
RUN mix quality.plt

Pre-commit hook

.git/hooks/pre-commit:

#!/bin/sh
mix quality --quick

Quick mode skips Dialyzer and coverage enforcement, which keeps the hook fast enough to live with. Leave the full run to CI.