ci: introduce knip (#10384)

### Description

[Knip](https://knip.dev/) is a tool that can help us to not leave unused
things around the repo. This PR introduces it to check for unused
dependencies in package.json. It's limited in how many packages in the
repo it is checking, but we can widen out its coverage over time.

### Testing Instructions

CI

Author: anthonyshew

.github/workflows/lint.yml

@@ -70,7 +70,7 @@ jobs:
       - name: Lint
         # Manually set TURBO_API to an empty string to override Hetzner env
         run: |
-          TURBO_API= turbo run lint --env-mode=strict
+          TURBO_API= turbo run lint knip --env-mode=strict
 
   cleanup:
     name: Cleanup

docs/site/app/(no-sidebar)/[...slug]/page.tsx

@@ -20,6 +20,7 @@ export default async function Page(props: {
   return (
     <article className="prose pt-10 mx-auto mb-10 w-full min-w-0 max-w-5xl px-6 md:px-12">
       <h1 className="text-left">{page.data.title}</h1>
+      {/* eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- Types not inferred correctly */}
       <Mdx components={mdxComponents} />
     </article>
   );

docs/site/app/(no-sidebar)/blog/[...slug]/page.tsx

@@ -61,6 +61,7 @@ export default async function Page(props: {
         </Link>
       </div>
 
+      {/* eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- Types not inferred correctly */}
       <Mdx components={mdxComponents} />
     </article>
   );

docs/site/app/(sidebar)/docs/[[...slug]]/page.tsx

@@ -61,6 +61,7 @@ export default async function Page(props: {
 
         <CopyToMarkdown markdownContent={rawMarkdown} />
       </div>
+      {/* eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- Types not inferred correctly */}
       <Mdx components={mdxComponents} />
     </>
   );

docs/site/package.json

@@ -20,7 +20,6 @@
     "collect-examples-data": "node ./scripts/collect-examples-data.mjs"
   },
   "dependencies": {
-    "@headlessui/react": "^1.7.17",
     "@heroicons/react": "1.0.6",
     "@radix-ui/react-collapsible": "^1.1.3",
     "@radix-ui/react-dialog": "^1.1.6",
@@ -31,7 +30,6 @@
     "@radix-ui/react-slot": "^1.1.2",
     "@radix-ui/react-tooltip": "^1.1.8",
     "@react-spring/web": "^9.7.3",
-    "@turbo/gen": "workspace:*",
     "@vercel/speed-insights": "1.2.0",
     "algoliasearch": "^4.23.3",
     "class-variance-authority": "^0.7.1",
@@ -59,13 +57,11 @@
     "zod": "^3.24.2"
   },
   "devDependencies": {
-    "@mdx-js/mdx": "^3.0.1",
     "@next/env": "15.3.1-canary.12",
-    "@turbo/eslint-config": "workspace:*",
     "@next/eslint-plugin-next": "15.3.1-canary.12",
+    "@turbo/eslint-config": "workspace:*",
     "@turbo/tsconfig": "workspace:^",
     "@turbo/types": "workspace:*",
-    "@types/mdx": "^2.0.8",
     "@types/node": "20.11.30",
     "@types/react": "18.3.1",
     "@types/react-dom": "18.3.0",
@@ -75,7 +71,6 @@
     "autoprefixer": "^10.4.20",
     "eslint": "8.57.0",
     "gray-matter": "^4.0.3",
-    "openapi-types": "^12.1.3",
     "postcss": "^8.4.35",
     "rss": "^1.2.2",
     "spellchecker-cli": "^6.2.0",

knip.jsonc

@@ -0,0 +1,22 @@
+{
+  "$schema": "https://unpkg.com/knip@5/schema-jsonc.json",
+  "ignore": [
+    "turborepo-tests/**",
+    // Not working well for this package for some reason
+    "docs/link-checker/**",
+    // TODO: Widen coverage
+    "packages/**"
+  ],
+  "workspaces": {
+    "docs/site": {
+      "ignoreDependencies": [
+        // TODO: We're using this but its getting reported?
+        "copy-to-clipboard",
+        "@next/env",
+        "@next/eslint-plugin-next",
+        "rss",
+        "@radix-ui/react-dropdown-menu"
+      ]
+    }
+  }
+}

package.json

@@ -9,6 +9,7 @@
     "lint:prettier": "turbo run lint:prettier",
     "check:toml": "taplo format --check",
     "docs:dev": "turbo run dev --filter=turborepo-docs",
+    "knip": "knip --include dependencies",
     "turbo": "pnpm run build:turbo && node turbow.js",
     "turbo-prebuilt": "node turbow.js",
     "prepare": "husky install",
@@ -19,8 +20,10 @@
   },
   "devDependencies": {
     "@taplo/cli": "^0.5.2",
+    "@types/node": "^22.15.1",
     "eslint": "^8.55.0",
     "husky": "^8.0.0",
+    "knip": "^5.50.5",
     "lint-staged": "^13.1.0",
     "prettier": "^2.8.7",
     "semver": "^7.3.8",