This PR attempts to break `codex-rust-review.md` into sections so that
it is easier to consume.
It also adds a healthy new section on "Assertions in Tests" that has
been on my mind for awhile.
The goal of this change is to try an experiment where we try to get AI
to take on more of the code review load. The idea is that once you
believe your PR is ready for review, please add the `codex-rust-review`
label (as opposed to the `codex-review` label).
Admittedly the corresponding prompt currently represents my personal
biases in terms of code review, but we should massage it over time to
represent the team's preferences.
This is a first cut at a GitHub Action that lets you define prompt
templates in `.md` files under `.github/codex/labels` that will run
Codex with the associated prompt when the label is added to a GitHub
pull request.
For example, this PR includes these files:
```
.github/codex/labels/codex-attempt.md
.github/codex/labels/codex-code-review.md
.github/codex/labels/codex-investigate-issue.md
```
And the new `.github/workflows/codex.yml` workflow declares the
following triggers:
```yaml
on:
issues:
types: [opened, labeled]
pull_request:
branches: [main]
types: [labeled]
```
as well as the following expression to gate the action:
```
jobs:
codex:
if: |
(github.event_name == 'issues' && (
(github.event.action == 'labeled' && (github.event.label.name == 'codex-attempt' || github.event.label.name == 'codex-investigate-issue'))
)) ||
(github.event_name == 'pull_request' && github.event.action == 'labeled' && github.event.label.name == 'codex-code-review')
```
Note the "actor" who added the label must have write access to the repo
for the action to take effect.
After adding a label, the action will "ack" the request by replacing the
original label (e.g., `codex-review`) with an `-in-progress` suffix
(e.g., `codex-review-in-progress`). When it is finished, it will swap
the `-in-progress` label with a `-completed` one (e.g.,
`codex-review-completed`).
Users of the action are responsible for providing an `OPENAI_API_KEY`
and making it available as a secret to the action.
