Set up CI

.github/workflows/ci.yml

@@ -0,0 +1,85 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+# Cancel in-progress runs for the same ref when a new commit lands.
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check:
+    name: Typecheck, lint, build
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up pnpm
+        # Reads the pnpm version from package.json#packageManager.
+        uses: pnpm/action-setup@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "24"
+          cache: pnpm
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Typecheck
+        run: pnpm typecheck
+
+      - name: Lint
+        run: pnpm lint
+
+      - name: Build
+        run: pnpm build
+
+  test:
+    name: Test (${{ matrix.name }})
+    needs: check
+    runs-on: ubuntu-latest
+    timeout-minutes: 25
+    strategy:
+      # Always run both backends so a regression in one is visible even if the
+      # other fails first.
+      fail-fast: false
+      matrix:
+        include:
+          # WebSocket suite hits wss://sync3.automerge.org.
+          - name: WebSocket backend
+            script: test:websocket
+          # Subduction suite hits wss://subduction.sync.inkandswitch.com via
+          # the --sub flag (plus pure-unit Subduction tests).
+          - name: Subduction backend
+            script: test:subduction
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up pnpm
+        uses: pnpm/action-setup@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "24"
+          cache: pnpm
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Build
+        # Several integration tests shell out to `dist/cli.js`, so the build
+        # artifact must exist before tests run.
+        run: pnpm build
+
+      - name: Test
+        run: pnpm run ${{ matrix.script }}
+        timeout-minutes: 20

eslint.config.mjs

@@ -0,0 +1,41 @@
+// Minimal ESLint flat config for pushwork.
+//
+// Goal: catch genuine bugs (undeclared bindings, unreachable code, etc.) without
+// nitpicking existing style — formatting belongs to Prettier (.prettierrc).
+//
+// Most stylistic rules from typescript-eslint's `recommended` set are toned down
+// here so this can run green on the existing codebase. Tighten over time.
+import tseslint from "typescript-eslint";
+
+export default tseslint.config(
+  {
+    ignores: ["dist/**", "node_modules/**", "coverage/**", "**/*.d.ts"],
+  },
+  ...tseslint.configs.recommended,
+  {
+    rules: {
+      "@typescript-eslint/ban-ts-comment": "off",
+      "@typescript-eslint/no-empty-object-type": "off",
+      "@typescript-eslint/no-explicit-any": "off",
+      "@typescript-eslint/no-non-null-assertion": "off",
+      "@typescript-eslint/no-require-imports": "off",
+      "@typescript-eslint/no-unused-expressions": "off",
+      "@typescript-eslint/no-unused-vars": [
+        "warn",
+        {
+          argsIgnorePattern: "^_",
+          varsIgnorePattern: "^_",
+          caughtErrorsIgnorePattern: "^_",
+        },
+      ],
+      "no-empty": ["warn", { allowEmptyCatch: true }],
+      // `ignoreReadBeforeAssign` keeps the rule from flagging the legitimate
+      // pattern where a `let` is declared first so it can be captured by a
+      // closure defined immediately afterward, and is then assigned later
+      // (e.g. `let timer; const cleanup = () => clearTimeout(timer); timer = setTimeout(...)`).
+      // Rewriting those to `const` would force restructuring just to silence
+      // the lint without any real readability gain.
+      "prefer-const": ["warn", { ignoreReadBeforeAssign: true }],
+    },
+  },
+);

package.json

@@ -14,10 +14,12 @@
 		"dev": "tsc --watch",
 		"test": "jest",
 		"test:bail": "jest --bail",
-		"test:watch": "jest --watch",
 		"test:coverage": "jest --coverage",
-		"lint": "eslint src --ext .ts",
-		"lint:fix": "eslint src --ext .ts --fix",
+		"test:subduction": "jest test/unit/repo-factory.test.ts test/unit/network-sync-sub.test.ts test/unit/subduction-config.test.ts test/integration/sub-flag.test.ts",
+		"test:watch": "jest --watch",
+		"test:websocket": "jest --testPathIgnorePatterns=/node_modules/ --testPathIgnorePatterns=\"(repo-factory|network-sync-sub|subduction-config|sub-flag)[.]test[.]ts$\"",
+		"lint": "eslint src",
+		"lint:fix": "eslint src --fix",
 		"clean": "rm -rf dist",
 		"prepack": "pnpm run build",
 		"start": "node dist/cli.js",
@@ -61,12 +63,14 @@
 		"@types/node": "^20.0.0",
 		"@types/tmp": "^0.2.4",
 		"babel-jest": "^30.2.0",
+		"eslint": "^9.18.0",
 		"fast-check": "^4.3.0",
 		"jest": "^29.7.0",
 		"tmp": "^0.2.1",
 		"ts-jest": "^29.1.0",
 		"tsx": "^4.19.2",
-		"typescript": "^5.2.0"
+		"typescript": "^5.2.0",
+		"typescript-eslint": "^8.20.0"
 	},
 	"jest": {
 		"preset": "ts-jest",
@@ -86,6 +90,7 @@
 		"setupFilesAfterEnv": [
 			"<rootDir>/test/jest.setup.ts"
 		],
+		"globalSetup": "<rootDir>/test/jest.globalSetup.ts",
 		"maxWorkers": "75%",
 		"maxConcurrency": 10,
 		"transformIgnorePatterns": [