Add PR checklist validation to pr-description-check action

[pxLi]

Fix NVIDIA/cudf-spark#14457

Summary

Some checklist items may be unexpectedly removed from PR descriptions. This change extends the pr-description-check action to verify that all required checklist items from the repo's PR template are still present in the PR body.

How it works

1. Fetches .github/PULL_REQUEST_TEMPLATE.md from the caller repo via GitHub API at runtime
2. Extracts all - [ ] checklist items from the template
3. Verifies each item exists in the PR body (accepts - [ ], - [x], or - [X])
4. Reports missing items with a clear failure message

Key design decisions

• No hardcoded checklist items — reads the template dynamically via GitHub API, so the check auto-adapts when the template changes
• Single commit status — both the HTML comment check and checklist check report under one PR Description status context
• Graceful fallbacks — skips silently if the template file doesn't exist (404) or has no checklist items; re-throws on unexpected API errors (auth,
  rate limit, 500)
• Configurable template path — new optional template-path input (defaults to .github/PULL_REQUEST_TEMPLATE.md)
• Backward compatible — no changes required in caller repos; existing workflows pick this up automatically

Verified in forked repos

Has HTML comments, missing checklist items.

Has HTML comments only,

Missing checklist items only,

Passed,

No template,

[greptile-apps]

Greptile Summary

This PR extends the pr-description-check composite action to validate that all required checklist items from the caller repo's PR template are still present in a PR's description, in addition to the existing HTML comment check. Both checks now share a single PR Description commit status context.

Key changes and observations:

• The previously flagged concern about an unguarded getContent response (directory array or >1MB file) has been addressed — the new type !== 'file' || content == null guard on lines 59–60 handles both cases cleanly before attempting base64 decoding.
• Checklist item matching correctly accepts - [ ], - [x], and - [X] variants in the PR body, and uses .trim() to handle trailing carriage-returns from CRLF line endings.
• Graceful fallback for a missing template (HTTP 404) and empty checklist sections (no items found) ensures backward compatibility and no false positives for repos without a template.
• Passing template-path via process.env.TEMPLATE_PATH rather than direct string interpolation into the script avoids potential script injection, which is the correct pattern for actions/github-script.
• The core.setFailed call does not interrupt execution (it only sets the process exit code), so createCommitStatus is always reached — this is the intended behavior and is correctly implemented.

Confidence Score: 5/5

• This PR is safe to merge; the implementation is correct and the previously raised concern has been fully addressed.
• All edge cases (404, directory listing, large file, no checklist items) are handled gracefully. The regex correctly captures single-line checklist items with CRLF tolerance via .trim(). The core.setFailed/createCommitStatus ordering is intentional and correct. No P0 or P1 issues found. The previously flagged non-file guard issue has been resolved in this revision.
• No files require special attention.

Important Files Changed

Filename	Overview
pr-description-check/action.yml	Extends the composite action to validate PR template checklist items alongside the existing HTML comment check. Handles edge cases (404, directory, >1MB file) correctly with guards. Logic is clean and backward-compatible.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A([PR event triggered]) --> B[Fetch PR body and SHA]
    B --> C{PR body contains HTML comment?}
    C -- Yes --> D[errors: has HTML comments]
    C -- No --> E[Continue]
    D --> E

    E --> F[Fetch PR template via getContent API]
    F --> G{HTTP 404?}
    G -- Yes --> H[Skip checklist check]
    G -- No --> I{type is not file or content is null?}
    I -- Yes --> J[Skip checklist check]
    I -- No --> K[Decode base64 to templateContent]

    K --> L[Extract unchecked items from template]
    L --> M{templateItems length > 0?}
    M -- No --> N[Skip checklist check]
    M -- Yes --> O[Extract all items from PR body into Set]
    O --> P[Filter template items not in body Set]
    P --> Q{Missing items found?}
    Q -- Yes --> R[errors: missing checklist items]
    Q -- No --> S[Continue]
    R --> S

    H --> T{Any errors?}
    J --> T
    N --> T
    S --> T

    T -- Yes --> U[core.setFailed with detailed message]
    T -- No --> V[statusDesc = PR description is valid]
    U --> W[createCommitStatus state=failure]
    V --> X[createCommitStatus state=success]

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_{Reviews (2): Last reviewed commit: "address comments" | Re-trigger Greptile}