Repository: vercel/next.js
Pull request: suggested fix for issue #74564

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Fixes #74564

The idea for the fix is from https://github.com/vercel/next.js/commit/fbf9e12de095e0237d4ba4aa6139d9757bd20be9#diff-907b7be0cfc75bd37773e5ebc38d1deffa40861b8ac1cde92e4992e284a1ee59R1221 I use the same nodejs [pathToFileURL](https://nodejs.org/api/url.html#urlpathtofileurlpath-options)  (https://github.com/vercel/next.js/blob/canary/packages/next/src/lib/find-config.ts#L74)

Changed files:
filename: packages/next-mdx/mdx-js-loader.js
patch: @@ -1,13 +1,18 @@
 const mdxLoader = require('@mdx-js/loader')
+const { pathToFileURL } = require('node:url')
 
 function interopDefault(mod) {
   return mod.default || mod
 }
 
 async function importPlugin(plugin, projectRoot) {
   if (Array.isArray(plugin) && typeof plugin[0] === 'string') {
+    const path = require.resolve(plugin[0], { paths: [projectRoot] })
     plugin[0] = interopDefault(
-      await import(require.resolve(plugin[0], { paths: [projectRoot] }))
+      // "use pathToFileUrl to make esm import()s work with absolute windows paths":
+      // on windows import("C:\\path\\to\\file") is not valid, so we need to use file:// URLs
+      // https://github.com/vercel/next.js/commit/fbf9e12de095e0237d4ba4aa6139d9757bd20be9
+      await import(process.platform === 'win32' ? pathToFileURL(path) : path)
     )
   }
   return plugin