fix: don't use resolved paths if they don't actually exist

Previously `toFilePath` would treat _any_ absolute path that doesn't
start with the `root` (usually the current working directory) as a
relative path, which resulted in some seriously mangled paths. Now we
actually check if that resolved path exists before committing to it.

This fixes #1864.

packages/vite-node/src/utils.ts

@@ -1,4 +1,5 @@
 import { fileURLToPath, pathToFileURL } from 'url'
+import { existsSync } from 'fs'
 import { resolve } from 'pathe'
 import type { TransformResult } from 'vite'
 import type { Arrayable, Nullable } from './types'
@@ -46,13 +47,18 @@ export function isPrimitive(v: any) {
 }
 
 export function toFilePath(id: string, root: string): string {
-  let absolute = id.startsWith('/@fs/')
-    ? id.slice(4)
-    : id.startsWith(root)
-      ? id
-      : id.startsWith('/')
-        ? resolve(root, id.slice(1))
-        : id
+  let absolute = (() => {
+    if (id.startsWith('/@fs/'))
+      return id.slice(4)
+    if (!id.startsWith(root) && id.startsWith('/')) {
+      const resolved = resolve(root, id.slice(1))
+      // The resolved path can have query values. Remove them before checking
+      // the file path.
+      if (existsSync(resolved.replace(/\?.*$/, '')))
+        return resolved
+    }
+    return id
+  })()
 
   if (absolute.startsWith('//'))
     absolute = absolute.slice(1)

test/core/test/file-path.test.ts

@@ -1,6 +1,9 @@
+import { existsSync } from 'fs'
 import { describe, expect, it, vi } from 'vitest'
 import { isWindows, slash, toFilePath } from '../../../packages/vite-node/src/utils'
 
+vi.mock('fs')
+
 describe('toFilePath', () => {
   // the following tests will work incorrectly on unix systems
   if (isWindows) {
@@ -37,8 +40,10 @@ describe('toFilePath', () => {
       const expected = '/path/to/project/node_modules/pkg/file.js'
 
       const processSpy = vi.spyOn(process, 'cwd').mockReturnValue(root)
+      const existsSpy = vi.mocked(existsSync).mockReturnValue(true)
       const filePath = toFilePath(id, root)
       processSpy.mockRestore()
+      existsSpy.mockRestore()
 
       expect(slash(filePath)).toEqual(expected)
     })
@@ -49,8 +54,11 @@ describe('toFilePath', () => {
       const expected = '/path/to/project/node_modules/pkg/file.js'
 
       const processSpy = vi.spyOn(process, 'cwd').mockReturnValue(root)
+      const existsSpy = vi.mocked(existsSync).mockReturnValue(true)
       const filePath = toFilePath(id, root)
       processSpy.mockRestore()
+      existsSpy.mockRestore()
+
       expect(slash(filePath)).toEqual(expected)
     })
 
@@ -60,8 +68,10 @@ describe('toFilePath', () => {
       const expected = '/root/node_modules/pkg/file.js'
 
       const processSpy = vi.spyOn(process, 'cwd').mockReturnValue(root)
+      const existsSpy = vi.mocked(existsSync).mockReturnValue(true)
       const filePath = toFilePath(id, root)
       processSpy.mockRestore()
+      existsSpy.mockRestore()
 
       expect(slash(filePath)).toEqual(expected)
     })
@@ -72,8 +82,10 @@ describe('toFilePath', () => {
       const expected = '/root/node_modules/pkg/file.js'
 
       const processSpy = vi.spyOn(process, 'cwd').mockReturnValue(root)
+      const existsSpy = vi.mocked(existsSync).mockReturnValue(true)
       const filePath = toFilePath(id, root)
       processSpy.mockRestore()
+      existsSpy.mockRestore()
 
       expect(slash(filePath)).toEqual(expected)
     })
@@ -84,10 +96,25 @@ describe('toFilePath', () => {
       const expected = '/root/path/to/file.js'
 
       const processSpy = vi.spyOn(process, 'cwd').mockReturnValue(root)
+      const existsSpy = vi.mocked(existsSync).mockReturnValue(true)
       const filePath = toFilePath(id, root)
       processSpy.mockRestore()
+      existsSpy.mockRestore()
 
       expect(slash(filePath)).toEqual(expected)
     })
+
+    it('unix with sibling path', () => {
+      const root = '/path/to/first/package'
+      const id = '/path/to/second/package/file.js'
+
+      const processSpy = vi.spyOn(process, 'cwd').mockReturnValue(root)
+      const existsSpy = vi.mocked(existsSync).mockReturnValue(false)
+      const filePath = toFilePath(id, root)
+      processSpy.mockRestore()
+      existsSpy.mockRestore()
+
+      expect(slash(filePath)).toEqual(id)
+    })
   }
 })

test/path-res-target/.eslintignore

@@ -0,0 +1 @@
+!dist/

test/path-res-target/.gitignore

@@ -0,0 +1 @@
+!dist/

test/path-res-target/README.md

@@ -0,0 +1,2 @@
+This package is here just to be a sibling package to `path-resolution`. It
+contains no tests of its own.

test/path-res-target/dist/index.d.ts

@@ -0,0 +1 @@
+export function sub(a: number, b: number): number

test/path-res-target/dist/index.js

@@ -0,0 +1,3 @@
+export function sub(a, b) {
+  return a - b;
+}

test/path-res-target/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "@vitest/test-path-res-target",
+  "type": "module",
+  "private": true,
+  "main": "./dist/index.js"
+}

test/path-resolution/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "@vitest/test-path-resolution",
+  "type": "module",
+  "private": true,
+  "scripts": {
+    "test": "vitest",
+    "coverage": "vitest run --coverage"
+  },
+  "devDependencies": {
+    "@edge-runtime/vm": "1.1.0-beta.26",
+    "@vitest/test-path-res-target": "workspace:*",
+    "@vitest/web-worker": "workspace:*",
+    "vitest": "workspace:*"
+  }
+}

test/path-resolution/test/sister-package.test.ts

@@ -0,0 +1,17 @@
+import { expect, it, vitest } from 'vitest'
+
+import { sub } from '@vitest/test-path-res-target'
+
+vitest.mock('@vitest/test-path-res-target')
+
+it('should be mocked', () => {
+  expect(sub).toHaveProperty('mock')
+  expect(sub(5, 3)).toBeUndefined()
+})
+
+it('should import actual', async () => {
+  const { sub } = await vitest.importActual('@vitest/test-path-res-target')
+
+  expect(sub).not.toHaveProperty('mock')
+  expect(sub(5, 3)).toBe(2)
+})

test/path-resolution/vitest.config.ts

@@ -0,0 +1,7 @@
+import { defineConfig } from 'vite'
+
+export default defineConfig({
+  test: {
+    include: ['test/*.test.ts'],
+  },
+})