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

1 files changed, 11 insertions, 3 deletions

diff --git a/ext/fs/30_fs.js b/ext/fs/30_fs.js
index f752c559a..2e7eba242 100644
--- a/ext/fs/30_fs.js
+++ b/ext/fs/30_fs.js
@@ -88,6 +88,7 @@ const {
   StringPrototypeStartsWith,
   SymbolAsyncIterator,
   SymbolIterator,
+  SymbolFor,
   Uint32Array,
 } = primordials;
 
@@ -619,7 +620,7 @@ function openSync(
     options,
   );
 
-  return new FsFile(rid);
+  return new FsFile(rid, SymbolFor("Deno.internal.FsFile"));
 }
 
 async function open(
@@ -632,7 +633,7 @@ async function open(
     options,
   );
 
-  return new FsFile(rid);
+  return new FsFile(rid, SymbolFor("Deno.internal.FsFile"));
 }
 
 function createSync(path) {
@@ -659,8 +660,15 @@ class FsFile {
   #readable;
   #writable;
 
-  constructor(rid) {
+  constructor(rid, symbol) {
     this.#rid = rid;
+    if (!symbol || symbol !== SymbolFor("Deno.internal.FsFile")) {
+      internals.warnOnDeprecatedApi(
+        "new Deno.FsFile()",
+        new Error().stack,
+        "Use `Deno.open` or `Deno.openSync` instead.",
+      );
+    }
   }
 
   get rid() {