fix(fs): instanceof check for Deno.FsFile (#22121)

Regression caused by https://github.com/denoland/deno/pull/22072.

I added a relevant test so we don't regress again.

Fixes https://github.com/denoland/deno/issues/22115

2 files changed, 11 insertions, 15 deletions

diff --git a/runtime/js/40_process.js b/runtime/js/40_process.js
index e6a62dcf7..ea99bcd97 100644
--- a/runtime/js/40_process.js
+++ b/runtime/js/40_process.js
@@ -21,6 +21,7 @@ const {
   PromisePrototypeThen,
   SafePromiseAll,
   Symbol,
+  SymbolFor,
 } = primordials;
 
 import { FsFile } from "ext:deno_fs/30_fs.js";
@@ -76,15 +77,21 @@ class Process {
     this.pid = res.pid;
 
     if (res.stdinRid && res.stdinRid > 0) {
-      this.stdin = new FsFile(res.stdinRid);
+      this.stdin = new FsFile(res.stdinRid, SymbolFor("Deno.internal.FsFile"));
     }
 
     if (res.stdoutRid && res.stdoutRid > 0) {
-      this.stdout = new FsFile(res.stdoutRid);
+      this.stdout = new FsFile(
+        res.stdoutRid,
+        SymbolFor("Deno.internal.FsFile"),
+      );
     }
 
     if (res.stderrRid && res.stderrRid > 0) {
-      this.stderr = new FsFile(res.stderrRid);
+      this.stderr = new FsFile(
+        res.stderrRid,
+        SymbolFor("Deno.internal.FsFile"),
+      );
     }
   }
 
diff --git a/runtime/js/90_deno_ns.js b/runtime/js/90_deno_ns.js
index 33fc2a6ff..98cc9f14d 100644
--- a/runtime/js/90_deno_ns.js
+++ b/runtime/js/90_deno_ns.js
@@ -31,17 +31,6 @@ import * as kv from "ext:deno_kv/01_db.ts";
 import * as cron from "ext:deno_cron/01_cron.ts";
 import * as webgpuSurface from "ext:deno_webgpu/02_surface.js";
 
-class FsFile extends fs.FsFile {
-  constructor(rid) {
-    super(rid);
-    internals.warnOnDeprecatedApi(
-      "Deno.Fs",
-      new Error().stack,
-      "Use `Deno.open()` or `Deno.openSync()` instead.",
-    );
-  }
-}
-
 const denoNs = {
   metrics: () => {
     internals.warnOnDeprecatedApi("Deno.metrics()", new Error().stack);
@@ -171,7 +160,7 @@ const denoNs = {
     return io.writeSync(rid, data);
   },
   File: fs.File,
-  FsFile,
+  FsFile: fs.FsFile,
   open: fs.open,
   openSync: fs.openSync,
   create: fs.create,