feat(eslint-plugin): no-void-queryFn (#8925)

* feat(eslint-plugin-query): implement no-void-query-fn rule

* add docs

* ci: apply automated fixes

* build(eslint-plugin-query): switch from vite to tsup for building

* update lockfile

* revert lockfile

* fix

* fix publint

* chore: add script to patch missing export equals

* ci: apply automated fixes

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

Author: Newbie012

docs/eslint/eslint-plugin-query.md

@@ -98,3 +98,4 @@ Alternatively, add `@tanstack/query` to the plugins section, and configure the r
 - [@tanstack/query/stable-query-client](./stable-query-client.md)
 - [@tanstack/query/no-unstable-deps](./no-unstable-deps.md)
 - [@tanstack/query/infinite-query-property-order](./infinite-query-property-order.md)
+- [@tanstack/query/no-void-query-fn](./no-void-query-fn.md)

docs/eslint/no-void-query-fn.md

@@ -0,0 +1,39 @@
+---
+id: no-void-query-fn
+title: Disallow returning void from query functions
+---
+
+Query functions must return a value that will be cached by TanStack Query. Functions that don't return a value (void functions) can lead to unexpected behavior and might indicate a mistake in the implementation.
+
+## Rule Details
+
+Example of **incorrect** code for this rule:
+
+```tsx
+/* eslint "@tanstack/query/no-void-query-fn": "error" */
+
+useQuery({
+  queryKey: ['todos'],
+  queryFn: async () => {
+    await api.todos.fetch() // Function doesn't return the fetched data
+  },
+})
+```
+
+Example of **correct** code for this rule:
+
+```tsx
+/* eslint "@tanstack/query/no-void-query-fn": "error" */
+useQuery({
+  queryKey: ['todos'],
+  queryFn: async () => {
+    const todos = await api.todos.fetch()
+    return todos
+  },
+})
+```
+
+## Attributes
+
+- [x] ✅ Recommended
+- [ ] 🔧 Fixable

knip.json

@@ -1,6 +1,11 @@
 {
   "$schema": "https://unpkg.com/knip@5/schema.json",
-  "ignore": [".pnpmfile.cjs", "scripts/*.js", "**/root.*.config.*"],
+  "ignore": [
+    ".pnpmfile.cjs",
+    "scripts/*.js",
+    "**/root.*.config.*",
+    "**/ts-fixture/file.ts"
+  ],
   "ignoreDependencies": [
     "@types/react",
     "@types/react-dom",

packages/eslint-plugin-query/package.json

@@ -6,7 +6,7 @@
   "license": "MIT",
   "repository": {
     "type": "git",
-    "url": "https://github.com/TanStack/query.git",
+    "url": "git+https://github.com/TanStack/query.git",
     "directory": "packages/eslint-plugin-query"
   },
   "homepage": "https://tanstack.com/query",
@@ -31,36 +31,35 @@
     "test:lib": "vitest",
     "test:lib:dev": "pnpm run test:lib --watch",
     "test:build": "publint --strict && attw --pack",
-    "build": "vite build"
+    "build": "tsup && node ./scripts/patch-missing-export-equals.js"
   },
   "type": "module",
-  "types": "dist/esm/index.d.ts",
-  "main": "dist/cjs/index.cjs",
-  "module": "dist/esm/index.js",
+  "types": "dist/index.d.ts",
+  "main": "dist/index.cjs",
+  "module": "dist/index.js",
   "exports": {
     ".": {
       "import": {
         "@tanstack/custom-condition": "./src/index.ts",
-        "types": "./dist/esm/index.d.ts",
-        "default": "./dist/esm/index.js"
+        "types": "./dist/index.d.ts",
+        "default": "./dist/index.js"
       },
       "require": {
-        "types": "./dist/cjs/index.d.cts",
-        "default": "./dist/cjs/index.cjs"
+        "types": "./dist/index.d.cts",
+        "default": "./dist/index.cjs"
       }
     },
     "./package.json": "./package.json"
   },
   "sideEffects": false,
   "files": [
-    "dist",
-    "src",
-    "!src/__tests__"
+    "dist"
   ],
   "dependencies": {
     "@typescript-eslint/utils": "^8.18.1"
   },
   "devDependencies": {
+    "@typescript-eslint/parser": "^8.18.1",
     "@typescript-eslint/rule-tester": "^8.18.1",
     "combinate": "^1.1.11",
     "eslint": "^9.15.0",

packages/eslint-plugin-query/scripts/patch-missing-export-equals.js

@@ -0,0 +1,20 @@
+// @ts-check
+
+// https://github.com/arethetypeswrong/arethetypeswrong.github.io/blob/main/docs/problems/MissingExportEquals.md
+
+import fs from 'node:fs/promises'
+import path from 'node:path'
+
+const projectDir = new URL('..', import.meta.url).pathname
+
+const dtsFiles = [
+  path.join(projectDir, 'dist/index.d.ts'),
+  path.join(projectDir, 'dist/index.d.cts'),
+]
+
+for (const file of dtsFiles) {
+  await fs.appendFile(file, '\n\nexport = plugin')
+  console.log(
+    `Appended \`export = plugin\` to ${path.relative(projectDir, file)}`,
+  )
+}