validate_pr.yml

name: PR Format Validation
permissions:
  contents: read

on:
  pull_request:
    types: [opened, edited, synchronize]

jobs:
  validate-pr:
    runs-on: ubuntu-latest
    steps:
      - name: Check for Spam PR
        uses: actions/github-script@v7
        with:
          script: |
            const prTitle = context.payload.pull_request.title;
            const spamRegex = /^(feat|chore|fix)(\(.*\))?\s*:/i;

            if (spamRegex.test(prTitle)) {
              // Leave a comment explaining why
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.payload.pull_request.number,
                body: `## PR Closed as Spam

            This PR was automatically closed because the title format \`feat:\`, \`fix:\`, or \`chore:\` is commonly associated with spam contributions.

            If this is a legitimate contribution, please:
            1. Review our contribution guidelines
            2. Use the correct PR title format: \`directory, ...: description\`
            3. Open a new PR with the proper title format

            Thank you for your understanding.`
              });

              // Close the PR
              await github.rest.pulls.update({
                owner: context.repo.owner,
                repo: context.repo.repo,
                pull_number: context.payload.pull_request.number,
                state: 'closed'
              });

              core.setFailed('PR closed as spam due to suspicious title format');
              return;
            }

            console.log('✅ PR passed spam check');

      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Check PR Title Format
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');
            const path = require('path');
            const prTitle = context.payload.pull_request.title;
            const titleRegex = /^([\w\s,{}/.]+): .+/;
            
            if (!titleRegex.test(prTitle)) {
              core.setFailed(`PR title "${prTitle}" does not match required format: directory, ...: description`);
              return;
            }

            const match = prTitle.match(titleRegex);
            const dirPart = match[1];
            const directories = dirPart.split(',').map(d => d.trim());
            const missingDirs = [];
            for (const dir of directories) {
              const fullPath = path.join(process.env.GITHUB_WORKSPACE, dir);
              if (!fs.existsSync(fullPath)) {
                missingDirs.push(dir);
              }
            }
            
            if (missingDirs.length > 0) {
              core.setFailed(`The following directories in the PR title do not exist: ${missingDirs.join(', ')}`);
              return;
            }
            
            console.log('✅ PR title format is valid');

      - name: Ensure PR Has a Nitro Companion
        uses: actions/github-script@v7
        with:
          script: |
            const prBody = context.payload.pull_request.body;
            const currentPrNumber = context.payload.pull_request.number;
            
            // --------------------------------------
            // --- 1. Check the Current PR's Body ---
            // --------------------------------------

            core.info(`Validating current PR description.`);
            
            if (!prBody) {
              core.setFailed("The PR description is empty. Please ensure it contains the required link.");
              return;
            }
            
            // The required regex pattern:
            // 1. Matches the literal string "pulled in by https://github.com/OffchainLabs/nitro/pull/"
            // 2. Requires one or more digits (\d+) for the pull request number (xxxx)
            // 3. The 'i' flag makes the entire match case-insensitive (e.g., "Pulled In By" is valid)
            const requiredRegex = /pulled in by https:\/\/github\.com\/OffchainLabs\/nitro\/pull\/(\d+)/i;
            const match = prBody.match(requiredRegex);
            
            if (!match) {
              core.setFailed("PR description validation failed. The description must contain a line matching the case-insensitive pattern: 'pulled in by https://github.com/OffchainLabs/nitro/pull/xxxx', where 'xxxx' is a number.");
              return;
            } else {
              core.info("✅ PR description contains the required link.");
            }

            const nitroPrNumber = match[1];
            core.info(`✅ Current PR contains 'pulled in by' link.`);
            core.info(`Found referenced Nitro PR number: #${nitroPrNumber}`);

            // ---------------------------------------------------
            // --- 2. Fetch the Referenced PR's Body ---
            // ---------------------------------------------------

            try {
              // Fetch the referenced PR details from the OffchainLabs/nitro repository.
              const referencedPr = await github.rest.pulls.get({
                owner: 'OffchainLabs',
                repo: 'nitro',
                pull_number: nitroPrNumber,
              });

              const referencedPrBody = referencedPr.data.body;
            
              if (!referencedPrBody || referencedPrBody.trim().length === 0) {
                core.setFailed(`Referenced Nitro PR #${nitroPrNumber} description is empty. The referenced PR must have a description.`);
                return;
              }

              // -----------------------------------------
              // --- 3. Check the Referenced PR's Body ---
              // -----------------------------------------

              // The inverse link must reference the current PR's number (yyy is currentPrNumber)
              // Pattern: "pulls in https://github.com/OffchainLabs/go-ethereum/pull/yyy"
              const inversePatternString = `pulls in https:\/\/github\.com\/OffchainLabs\/go-ethereum\/pull\/${currentPrNumber}`;
              const inverseRequiredRegex = new RegExp(inversePatternString, 'i');

              if (!inverseRequiredRegex.test(referencedPrBody)) {
                core.setFailed(`Inverse link validation failed on Nitro PR #${nitroPrNumber}. It must contain the case-insensitive link: 'pulls in https://github.com/OffchainLabs/go-ethereum/pull/${currentPrNumber}'`);
                return;
              }

              core.info(`✅ Referenced Nitro PR #${nitroPrNumber} contains the inverse link to go-ethereum PR #${currentPrNumber}.`);
              core.info("✅ All PR description cross-validations passed successfully.");

            } catch (error) {
              // Handle cases like "PR not found" or API errors
              core.setFailed(`Could not fetch or validate referenced PR #${nitroPrNumber} in OffchainLabs/nitro. API Error: ${error.message}`);
            }