cargo-dejadoc

Whoa, deja vu. A doctest went past us, and then another that looked just like it.

cargo dejadoc scans and canonicalizes every doctest your workspace's rustdoc would run, reporting any identified duplicates. Items are kept by their cfg as rustdoc sees them on a 64-bit Linux host with every feature on, test off and custom cfgs off.

The flags under cargo dejadoc --help restrict the package, set the threshold and minimum token count, point at a config file, and switch the output to JSON. Without flags, parameters come from .dejadoc.toml at the workspace root.

To allow a known copy, add the dejadoc token to the fence's info list, as in rust,dejadoc. rustdoc runs the doctest and ignores the unknown token, so nothing else about the site changes.

In CI, the composite action installs the crate and runs the gate.

- uses: LucaCappelletti94/cargo-dejadoc@v1
  with:
    threshold: 2

In a pull request, the action posts the findings as a review instead of failing the job.

on: pull_request
jobs:
  dejadoc:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
      - uses: actions/checkout@v4
      - uses: dtolnay/rust-toolchain@stable
      - uses: LucaCappelletti94/cargo-dejadoc@v1
        with:
          pr-number: ${{ github.event.pull_request.number }}

Every duplicated doctest whose file is in the pull request diff gets an inline comment naming the copy count and the kept original, the first copy marked as the one to keep and each later copy with a suggestion that deletes it, and the review requests changes. Each comment ends with a link that opens a prefilled issue here for reporting a wrong review and a heart link to support the project. Sites outside the diff get no comment, and when no site is in the diff the review is skipped.

A pull request from a fork runs with a read-only GITHUB_TOKEN, so the action logs a warning, skips the review, and the job passes. To review fork pull requests, trigger on pull_request_target and check out the pull request head as below. That trigger runs the job with write access, so read GitHub's guidance before opting the checkout in with allow-unsafe-pr-checkout.

on: pull_request_target
jobs:
  dejadoc:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
      - uses: actions/checkout@v7
        with:
          ref: ${{ github.event.pull_request.head.sha }}
          allow-unsafe-pr-checkout: true
      - uses: dtolnay/rust-toolchain@stable
      - uses: LucaCappelletti94/cargo-dejadoc@v1
        with:
          pr-number: ${{ github.event.pull_request.number }}

On a private repository, the setting Send write tokens to workflows from pull requests under Settings > Actions > General does the same without changing the trigger.

The library builds the same report in memory.

let report = dejadoc::Dejadoc::default().run("tests/fixtures/dupws").unwrap();
assert_eq!(report.groups.len(), 2);