fix(pnp): esm - handle parentURL without a file: protocol (#5362)

**What's the problem this PR addresses?**
When chaining Yarn PNP ESM loader with
[import-in-the-middle](https://github.com/DataDog/import-in-the-middle)
loader, INVALID_URL_SCHEME is thrown because `fileURLToPath()` is run on
a parent URL of `node:util?iitm=true` generated by the IITM loader.

```
2023-03-30T21:40:58.280Z 3364766 U TypeError [ERR_INVALID_URL_SCHEME]: The URL must be of scheme file
2023-03-30T21:40:58.280Z 3364766 U     at new NodeError (node:internal/errors:399:5)
2023-03-30T21:40:58.280Z 3364766 U     at fileURLToPath (node:internal/url:1212:11)
2023-03-30T21:40:58.280Z 3364766 U     at resolve$1 (file:///home/lizf/eve-roster/.pnp.loader.mjs:1993:77)
2023-03-30T21:40:58.280Z 3364766 U     at nextResolve (node:internal/modules/esm/hooks:654:28)
2023-03-30T21:40:58.280Z 3364766 U     at Hooks.resolve (node:internal/modules/esm/hooks:309:30)
2023-03-30T21:40:58.280Z 3364766 U     at ESMLoader.resolve (node:internal/modules/esm/loader:312:26)
2023-03-30T21:40:58.280Z 3364766 U     at ESMLoader.getModuleJob (node:internal/modules/esm/loader:172:38)
2023-03-30T21:40:58.281Z 3364766 U     at ModuleWrap.<anonymous> (node:internal/modules/esm/module_job:76:40)
2023-03-30T21:40:58.281Z 3364766 U     at link (node:internal/modules/esm/module_job:75:36) {
2023-03-30T21:40:58.281Z 3364766 U   code: 'ERR_INVALID_URL_SCHEME'
2023-03-30T21:40:58.281Z 3364766 U }
2023-03-30T21:40:58.281Z 3364766 U
2023-03-30T21:40:58.281Z 3364766 U Node.js v19.8.1
```

**How did you fix it?**
Ensure fileURLToPath() is only run on file URLs by explicitly checking
the URL protocol; if it is not `file`, then default to CWD.

**Checklist**
- [x] I have read the [Contributing
Guide](https://yarnpkg.com/advanced/contributing).
- [x] I have set the packages that need to be released for my changes to
be effective.
- [x] I will check that all automated PR checks pass before the PR gets
reviewed.

---------

Co-authored-by: merceyz <[email protected]>

Author: lizthegrey

.yarn/versions/1c86bcd3.yml

@@ -0,0 +1,27 @@
+releases:
+  "@yarnpkg/cli": patch
+  "@yarnpkg/plugin-pnp": patch
+  "@yarnpkg/pnp": patch
+
+declined:
+  - "@yarnpkg/plugin-compat"
+  - "@yarnpkg/plugin-constraints"
+  - "@yarnpkg/plugin-dlx"
+  - "@yarnpkg/plugin-essentials"
+  - "@yarnpkg/plugin-init"
+  - "@yarnpkg/plugin-interactive-tools"
+  - "@yarnpkg/plugin-nm"
+  - "@yarnpkg/plugin-npm-cli"
+  - "@yarnpkg/plugin-pack"
+  - "@yarnpkg/plugin-patch"
+  - "@yarnpkg/plugin-pnpm"
+  - "@yarnpkg/plugin-stage"
+  - "@yarnpkg/plugin-typescript"
+  - "@yarnpkg/plugin-version"
+  - "@yarnpkg/plugin-workspace-tools"
+  - "@yarnpkg/builder"
+  - "@yarnpkg/core"
+  - "@yarnpkg/doctor"
+  - "@yarnpkg/nm"
+  - "@yarnpkg/pnpify"
+  - "@yarnpkg/sdks"

packages/acceptance-tests/pkg-tests-specs/sources/pnp-esm.test.ts

@@ -1,5 +1,6 @@
-import {Filename, PortablePath, ppath, xfs} from '@yarnpkg/fslib';
-import * as loaderFlags                     from '@yarnpkg/pnp/sources/esm-loader/loaderFlags';
+import {Filename, PortablePath, npath, ppath, xfs} from '@yarnpkg/fslib';
+import * as loaderFlags                            from '@yarnpkg/pnp/sources/esm-loader/loaderFlags';
+import {pathToFileURL}                             from 'url';
 
 describe(`Plug'n'Play - ESM`, () => {
   test(
@@ -970,5 +971,61 @@ describe(`Plug'n'Play - ESM`, () => {
         },
       ),
     );
+
+    (loaderFlags.HAS_CONSOLIDATED_HOOKS ? test : test.skip)(
+      `it should allow importing files regardless of parent URL`,
+      makeTemporaryEnv(
+        {
+          type: `module`,
+        },
+        async ({path, run, source}) => {
+          await expect(run(`install`)).resolves.toMatchObject({code: 0});
+
+          await xfs.writeFilePromise(
+            ppath.join(path, `loader.js` as Filename),
+            `
+            export function resolve(specifier, context, next) {
+              if (specifier !== 'custom:foo') {
+                return next(specifier, context);
+              }
+
+              return {
+                shortCircuit: true,
+                url: 'custom:foo',
+              };
+            }
+
+            export function load(url, context, next) {
+              if (url !== 'custom:foo') {
+                return next(url, context);
+              }
+
+              return {
+                format: 'module',
+                source: "import { foo } from '${pathToFileURL(npath.fromPortablePath(ppath.join(path, `foo.js` as Filename)))}'\\nconsole.log(foo);",
+                shortCircuit: true,
+              };
+            }
+            `,
+          );
+
+          await xfs.writeFilePromise(
+            ppath.join(path, `foo.js` as Filename),
+            `export const foo = 42;`,
+          );
+
+          await xfs.writeFilePromise(
+            ppath.join(path, `index.js` as Filename),
+            `import 'custom:foo'`,
+          );
+
+          await expect(run(`node`, `--loader`, `./loader.js`, `./index.js`)).resolves.toMatchObject({
+            code: 0,
+            stdout: `42\n`,
+            stderr: ``,
+          });
+        },
+      ),
+    );
   });
 });

packages/yarnpkg-pnp/sources/esm-loader/built-loader.js

@@ -67,7 +67,7 @@ export async function resolve(
 
   const {parentURL, conditions = []} = context;
 
-  const issuer = parentURL ? fileURLToPath(parentURL) : process.cwd();
+  const issuer = parentURL && loaderUtils.tryParseURL(parentURL)?.protocol === `file:` ? fileURLToPath(parentURL) : process.cwd();
 
   // Get the pnpapi of either the issuer or the specifier.
   // The latter is required when the specifier is an absolute path to a