implement extra linting step

Author: Hweinstock

.github/workflows/lintbranch.js

@@ -0,0 +1,67 @@
+// Check that branch name conforms to GitHub naming convention:
+// https://docs.github.com/en/get-started/using-git/dealing-with-special-characters-in-branch-and-tag-names#naming-branches-and-tags
+
+// To run self-tests,
+// node lintbranch.js test
+// TODO: deduplicate code from lintbranch.js and lintcommit.js.
+
+function isValid(branchName) {
+    const branchNameRegex = /^[a-zA-Z][a-zA-Z0-9._/-]*$/
+
+    return branchNameRegex.test(branchName)
+}
+
+function run(branchName) {
+    if (isValid(branchName)) {
+        console.log(`Branch name "${branchName}" is valid.`)
+        process.exit(0)
+    } else {
+        const helpUrl =
+            'https://docs.github.com/en/get-started/using-git/dealing-with-special-characters-in-branch-and-tag-names#naming-branches-and-tags'
+        console.log(`Branch name "${branchName}" is invalid see ${helpUrl} for more information.`)
+        process.exit(1)
+    }
+}
+
+function _test() {
+    const tests = {
+        'feature/branch-name': true,
+        feature_123: true,
+        'my-branch': true,
+        '123invalid-start': false,
+        '!invalid@start': false,
+        '': false,
+        'another/valid-name134': true,
+        'Hweinstock:feature/123";id;{echo,Y2F0IC9ldGMvcGFzc3dk}|{base64,-d}|{bash,-i};#': false,
+    }
+
+    let passed = 0
+    let failed = 0
+
+    for (const [branchName, expected] of Object.entries(tests)) {
+        const result = isValid(branchName)
+        if (result === expected) {
+            console.log(`✅ Test passed for "${branchName}"`)
+            passed++
+        } else {
+            console.log(`❌ Test failed for "${branchName}" (expected "${expected}", got "${result}")`)
+            failed++
+        }
+    }
+
+    console.log(`\n${passed} tests passed, ${failed} tests failed`)
+}
+
+function main() {
+    const mode = process.argv[2]
+
+    if (mode === 'test') {
+        _test()
+    } else if (mode === 'run') {
+        run(process.argv[3])
+    } else {
+        throw new Error(`Unknown mode: ${mode}`)
+    }
+}
+
+main()

.github/workflows/node.js.yml

@@ -32,6 +32,9 @@ jobs:
             - uses: actions/setup-node@v4
               with:
                   node-version: '20'
+            - name: Check Branch title
+              run: |
+                  node "$GITHUB_WORKSPACE/.github/workflows/lintbranch.js"
             - name: Check PR title
               run: |
                   node "$GITHUB_WORKSPACE/.github/workflows/lintcommit.js"