fix: don't use resolved paths if they don't actually exist (#1868)

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 { relative, resolve } from 'pathe'
 import type { TransformResult } from 'vite'
 import { isNodeBuiltin } from 'mlly'
@@ -75,13 +76,18 @@ export function pathFromRoot(root: string, filename: string) {
 }
 
 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)