action.yaml

name: file-changes

description: Checks git diff against a group of regexes (JSON-like input) and returns key-value pairs of results.

inputs:
  before_sha:
    description: The previous SHA.
    required: true
  current_sha:
    description: The current SHA.
    required: true
  regex_group:
    description: |
      A JSON-like string of regex groups (e.g., '{"deps": ["**", "!cypress/e2e/dynamic/**/*.ts", "!cypress/e2e/web/**/*.ts"], "dynamic": ["cypress/e2e/dynamic/**/*.cy.ts"], "web": ["cypress/e2e/web/**/*.cy.ts"]}').
    required: true

outputs:
  results:
    description: The results of the regex group.
    value: ${{ steps.check.outputs.results }}

runs:
  using: composite
  steps:
    - name: Check file changes
      uses: actions/github-script@v7
      id: check
      with:
        script: |
          const { before_sha, current_sha, regex_group } = {
            before_sha: '${{ inputs.before_sha }}',
            current_sha: '${{ inputs.current_sha }}',
            regex_group: '${{ inputs.regex_group }}'
          };

          console.log({before_sha, current_sha, regex_group});
          
          async function getChangedFiles(before, current) {
            let stdout = '';
            const options = {
              listeners: {
                stdout: (data) => {
                  stdout += data.toString();
                }
              }
            };
            
            await exec.exec('git', ['diff', '--name-only', before, current], options);
            return stdout.split("\n").filter(Boolean);
          }
          
          async function processRegexGroup(before, current, regexGroup) {
            const parsedGroup = JSON.parse(regexGroup);
            const changedFiles = await getChangedFiles(before, current);
            const results = {};
            
            for (const [key, patterns] of Object.entries(parsedGroup)) {
              const positivePatterns = patterns.filter(p => !p.startsWith("!"));
              const negativePatterns = patterns.filter(p => p.startsWith("!")).map(p => p.substring(1));
              
              const positiveRegex =
                positivePatterns.length > 0
                  ? new RegExp(`(${positivePatterns.join('|')})`)
                  : null;

              const negativeRegex =
                negativePatterns.length > 0
                  ? new RegExp(`(${negativePatterns.join('|')})`)
                  : null;

              const matches = changedFiles.filter((file) => {
                const isPositiveMatch = positiveRegex ? positiveRegex.test(file) : true;
                const isNegativeMatch = negativeRegex ? negativeRegex.test(file) : false;
                return isPositiveMatch && !isNegativeMatch;
              });
              
              results[key] = matches.length > 0;
            }
            
            core.setOutput('results', JSON.stringify(results));
          }
          
          await processRegexGroup(before_sha, current_sha, regex_group);