chore(repo): implement CI w/ gitlab CI

`@websnacksjs/conventional` is a cli program which can be used with
`husky` & git hooks to enforce that commit messages adhere to the
conventional commits standard.

.github/workflows/ci.yml

@@ -1,24 +0,0 @@
-name: Continuous Integration (CI)
-
-on:
-  pull_request:
-    branches: [main]
-  push:
-    branches: [main]
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        node: [22, 24]
-    name: Node ${{ matrix.node }}
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
-        with:
-          node-version: ${{ matrix.node }}
-          cache: "npm"
-          cache-dependency-path: "package-lock.json"
-      - run: npm ci
-      - run: npm run test --workspaces --if-present

.gitignore

@@ -36,7 +36,7 @@
 !/flake.lock
 
 ### Repository configuration ###
-!/.github/workflows/*.yml
+!/.gitlab-ci.yml
 !/.husky/commit-msg
 !/conventional.config.js
 

.gitlab-ci.yml

@@ -0,0 +1,18 @@
+stages: [build, test]
+
+build:
+  stage: build
+  cache: &cached-deps
+    key:
+      files: [package-lock.json]
+    paths: [node_modules/]
+  script:
+    - npm ci
+    - npm run build --workspaces --if-present
+
+test:
+  stage: test
+  cache:
+    <<: &cached-deps
+  script:
+    - npm run test --workspaces --if-present

conventional.config.js

@@ -15,21 +15,14 @@ const validateRepoScopedCommit = (message) => {
 	}
 };
 
-const packagePrefix = "@websnacksjs/";
 const packages = await fs.readdir(new URL("./packages", import.meta.url));
+const validScopes = ["repo", ...packages];
 
 /**
  * @param {import("@websnacksjs/conventional").CommitMessage} message
  * @returns {void}
  */
 const validatePackageScopedCommit = (message) => {
-	const pkg = message.scope?.slice(packagePrefix.length) ?? "";
-	if (!packages.includes(pkg)) {
-		throw new Error(
-			`unknown package ${JSON.stringify(pkg)} referenced in commit scope`,
-		);
-	}
-
 	const supportedTypes = ["feat", "fix", "docs", "test", "chore"];
 	if (!supportedTypes.includes(message.type)) {
 		throw new Error(
@@ -39,6 +32,73 @@ const validatePackageScopedCommit = (message) => {
 	}
 };
 
+/**
+ * @param {string} value
+ * @returns {void}
+ */
+const validateUrl = (value) => {
+	try {
+		new URL(value);
+	} catch {
+		const error = new Error(
+			`expected valid URL but got ${JSON.stringify(value)}`,
+		);
+		Error.captureStackTrace(error, validateUrl);
+		throw error;
+	}
+};
+
+/**
+ * @param {import("@websnacksjs/conventional").Footer[]} footers
+ * @returns void
+ */
+const validateFooters = (footers) => {
+	/** @type {string[]} */
+	const unsupportedFooters = [];
+	/** @type {{footer: string, reason: Error}[]} */
+	const invalidFooters = [];
+	for (const { key, value } of footers) {
+		try {
+			switch (key) {
+				case "Merge-request": {
+					validateUrl(value);
+					break;
+				}
+				default: {
+					unsupportedFooters.push(key);
+				}
+			}
+		} catch (error) {
+			if (!(error instanceof Error)) {
+				throw new Error(
+					`caught unexpected non-error value ${JSON.stringify(error)}`,
+				);
+			}
+			invalidFooters.push({ footer: key, reason: error });
+		}
+	}
+
+	const errorMessageParts = [];
+	if (unsupportedFooters.length > 0) {
+		let message = `unspported footers in message:`;
+		for (const footer of unsupportedFooters) {
+			message += `\n\t- ${footer}`;
+		}
+		errorMessageParts.push(message);
+	}
+	if (invalidFooters.length > 0) {
+		let message = `invalid footers in message:`;
+		for (const { footer, reason } of invalidFooters) {
+			message += `\n\t- ${footer}: ${reason.message}`;
+		}
+		errorMessageParts.push(message);
+	}
+	if (errorMessageParts.length > 0) {
+		const message = errorMessageParts.join("\n\n");
+		throw new Error(message);
+	}
+};
+
 export default defineConfig({
 	validateCommitMessage(message) {
 		if (!message.scope) {
@@ -47,25 +107,19 @@ export default defineConfig({
 			);
 		}
 
-		if (message.footers.length > 0) {
+		if (message.scope === "repo") {
+			validateRepoScopedCommit(message);
+		} else if (packages.includes(message.scope)) {
+			validatePackageScopedCommit(message);
+		} else {
 			throw new Error(
-				`commit message footers are currently unsupported ` +
+				[
-					`(try removing them from your commit message)`,
+					`scope ${JSON.stringify(message.scope)} is unsupported`,
+					`(try one of ${JSON.stringify(validScopes).replace(",", ", ")})`,
+				].join(" "),
 			);
 		}
 
-		if (message.scope === "repo") {
+		validateFooters(message.footers);
-			validateRepoScopedCommit(message);
-			return;
-		}
-
-		if (message.scope.startsWith(packagePrefix)) {
-			validatePackageScopedCommit(message);
-			return;
-		}
-
-		throw new Error(
-			`scope ${JSON.stringify(message.scope)} is unsupported (try one of ["repo", "@websnacksjs/:package"])`,
-		);
 	},
 });