.github/workflows/labeler.yml

# SPDX-License-Identifier: Apache-2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# This workflow will fetch the updated PR filenames, compute the Size Label
# and Arch Labels, then save the PR Labels into a PR Artifact. The
# PR Labels will be written to the PR inside the "workflow_run" trigger
# (pr_labeler.yml), because this "pull_request" trigger has read-only
# permission. Don't use "pull_request_target", it's unsafe.
# See https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=321719166#GitHubActionsSecurity-Buildstriggeredwithpull_request_target
name: "Pull Request Labeler"
on:
  - pull_request

jobs:
  labeler:
    permissions:
      contents: read
      pull-requests: read
      issues: read
    runs-on: ubuntu-latest
    steps:
      # Checkout one file from our trusted source: .github/labeler.yml
      # Never checkout and execute any untrusted code from the PR.
      - name: Checkout labeler config
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
        with:
          repository: apache/nuttx
          ref: master
          path: labeler
          fetch-depth: 1
          persist-credentials: false
          sparse-checkout: .github/labeler.yml
          sparse-checkout-cone-mode: false

      # Fetch the updated PR filenames. Compute the Size Label and Arch Labels.
      - name: Compute PR labels
        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd  # v8.0.0
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const owner = context.repo.owner;
            const repo = context.repo.repo;
            const pull_number = context.issue.number;

            // Fetch the array of updated PR filenames:
            // { status: 'added',    filename: 'arch/arm/test.txt',              additions: 3, deletions: 0,    changes: 3 }
            // { status: 'removed',  filename: 'Documentation/legacy_README.md', additions: 0, deletions: 2531, changes: 2531 }
            // { status: 'modified', filename: 'Documentation/security.rst',     additions: 1, deletions: 0,    changes: 1 }
            const listFilesOptions = github.rest.pulls.listFiles
              .endpoint.merge({ owner, repo, pull_number });
            const listFilesResponse = await github.paginate(listFilesOptions);

            // Sum up the number of lines changed
            const sizeFiles = listFilesResponse
              .filter(f => (f.status != 'removed'));  // Ignore deleted files
            var linesChanged = 0;
            for (const file of sizeFiles) {
              linesChanged += file.changes;
            }
            console.log({ linesChanged });

            // Compute the Size Label
            const sizeLabel =
              (linesChanged   <=   10) ? 'Size: XS'
              : (linesChanged <=  100) ? 'Size: S'
              : (linesChanged <=  500) ? 'Size: M'
              : (linesChanged <= 1000) ? 'Size: L'
              : 'Size: XL';
            var prLabels = [ sizeLabel ];

            // Parse the Arch Label Patterns in .github/labeler.yml. Condense into:
            // "Arch: arm":
            // - any-glob-to-any-file: 'arch/arm/**'
            // - any-glob-to-any-file: ...
            const fs = require('fs');
            const config = fs.readFileSync('labeler/.github/labeler.yml', 'utf8')
              .split('\n')             // Split by newline
              .map(s => s.trim())      // Remove leading and trailing spaces
              .filter(s => (s != ''))  // Remove empty lines
              .filter(s => !s.startsWith('#'))                  // Remove comments
              .filter(s => !s.startsWith('- changed-files:'));  // Remove "changed-files"

            // Convert the Arch Label Patterns from config to archLabels.
            // archLabels will contain the mappings for Arch Label and Filename Pattern:
            // { label: "Arch: arm",   pattern: "arch/arm/.*"   },
            // { label: "Arch: arm64", pattern: "arch/arm64/.*" }, ...
            var archLabels = [];
            var label = "";
            for (const c of config) {
              // Get the Arch Label
              if (c.startsWith('"')) {    // "Arch: arm":
                label = c.split('"')[1];  // Arch: arm

              } else if (c.startsWith('- any-glob-to-any-file:')) {  // - any-glob-to-any-file: 'arch/arm/**'
                // Convert the Glob Pattern to Regex Pattern
                const pattern = c.split("'")[1]      // arch/arm/**
                  .split('.').join('\\.')            // .  becomes \.
                  .split('*').join('[^/]*')          // *  becomes [^/]*
                  .split('[^/]*[^/]*').join('.*');   // ** becomes .*
                archLabels.push({
                  label,                        // Arch: arm
                  pattern: '^' + pattern + '$'  // Match the Line Start and Line End
                });

              } else {
                // We don't support all rules of `actions/labeler`
                throw new Error('.github/labeler.yml should contain only changed-files and any-glob-to-any-file, not: ' + c);
              }
            }

            // Search the filenames for matching Arch Labels
            for (const archLabel of archLabels) {
              if (prLabels.includes(archLabel.label)) {
                break;
              }
              for (const file of listFilesResponse) {
                const re = new RegExp(archLabel.pattern);
                const match = re.test(file.filename);
                if (match && !prLabels.includes(archLabel.label)) {
                  prLabels.push(archLabel.label);
                  break;
                }
              }
            }
            console.log({ prLabels });

            // Save the PR Number and PR Labels into a PR Artifact
            // e.g. 'Size: XS\nArch: avr\n'
            const dir = 'pr';
            fs.mkdirSync(dir);
            fs.writeFileSync(dir + '/pr-id.txt', pull_number + '\n');
            fs.writeFileSync(dir + '/pr-labels.txt', prLabels.join('\n') + '\n');

      # Upload the PR Artifact as pr.zip
      - name: Upload PR artifact
        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f  # v7.0.0
        with:
          name: pr
          path: pr/