feat: add --pr-only flag

README.md

@@ -8,3 +8,17 @@ from `@commitlint/travis-cli`.
 Only supports `git` projects, assumes a single repository (i.e. does not explicitly support cross-
 repo pull requests), and doesn't support renaming the remote to something other than `origin`. We
 welcome [pull requests](https://github.com/mixmaxhq/commitlint-jenkins/pulls)!
+
+## Flags
+
+### `--if-ci`
+
+If `commitlint-jenkins` is run outside of a CI context, it will fail. This flag simply ignores the
+failure, for use-cases where `commitlint-jenkins` should be run from a script shared with a non-CI
+workflow.
+
+### `--pr-only`
+
+If `commitlint-jenkins` is run in CI in a build that isn't a pull request build, silently exit.
+This flag is particularly handy for use with
+[`@mixmaxhq/semantic-commitlint`](https://github.com/mixmaxhq/semantic-commitlint).

package.json

@@ -11,7 +11,8 @@
   ],
   "scripts": {
     "ci": "npm run lint",
-    "lint": "eslint . && node . --if-ci",
+    "ci:commitlint": "node . --pr-only",
+    "lint": "eslint .",
     "prepublishOnly": "if [ \"$CI\" = '' ]; then node -p 'JSON.parse(process.env.npm_package_config_manualPublishMessage)'; exit 1; fi",
     "test": "echo \"Error: no test specified\" && exit 1",
     "semantic-release": "semantic-release"

src/index.js

@@ -4,9 +4,9 @@ const argv = require('yargs').argv;
 const commitlint = require('@commitlint/cli');
 
 const IF_CI = !!argv.ifCi;
+const PR_ONLY = !!argv.prOnly;
 
-// Allow to override used bins for testing purposes
-const GIT = process.env.JENKINS_COMMITLINT_GIT_BIN || 'git';
+// Allow override of used bins for testing purposes
 const COMMITLINT = process.env.JENKINS_COMMITLINT_BIN;
 
 const REQUIRED = ['GIT_COMMIT'];
@@ -40,14 +40,16 @@ async function main() {
     // We could lint since the last successful commit, but that would require a bunch of extra logic
     // to detect changes to commitlint.config.js or related modules.
     await lint(['--from', start, '--to', COMMIT]);
-  } else {
+  } else if (!PR_ONLY) {
+    // The --pr-only flag can be useful to use semantic-commitlint on the release branch instead of
+    // just linting one commit.
     const input = await rawCommit(COMMIT);
     await lint([], { input });
   }
 }
 
 async function getBase({ branch, tip = 'HEAD' }) {
-  const result = await execa(GIT, ['merge-base', branch, tip]);
+  const result = await execa('git', ['merge-base', branch, tip]);
   return result.stdout;
 }
 
@@ -59,7 +61,7 @@ async function lint(args, options) {
 }
 
 async function rawCommit(hash) {
-  const result = await execa(GIT, ['show', '--pretty=format:%B', hash]);
+  const result = await execa('git', ['show', '-s', '--pretty=format:%B', hash]);
   return result.stdout;
 }