FUTURE(ext/fs): make `Deno.FsFile` constructor illegal (#23235)

I'm unsure whether we're planning to make the `Deno.FsFile` constructor
illegal or remove `FsFile` from the `Deno.*` namspace in Deno 2. Either
way, this PR works towards the former. I'll create a superceding PR if
the latter is planned instead.

Towards #23089

1 files changed, 12 insertions, 0 deletions

diff --git a/tests/specs/future/runtime_api/main.js b/tests/specs/future/runtime_api/main.js
index ed60a7b7c..9d3b3ed6c 100644
--- a/tests/specs/future/runtime_api/main.js
+++ b/tests/specs/future/runtime_api/main.js
@@ -31,4 +31,16 @@ console.log("Deno.writeAllSync is", Deno.writeAllSync);
 console.log("Deno.write is", Deno.write);
 console.log("Deno.writeSync is", Deno.writeSync);
 
+try {
+  new Deno.FsFile(0);
+} catch (error) {
+  if (
+    error instanceof TypeError &&
+    error.message ===
+      "`Deno.FsFile` cannot be constructed, use `Deno.open()` or `Deno.openSync()` instead."
+  ) {
+    console.log("Deno.FsFile constructor is illegal");
+  }
+}
+
 self.close();