fix(webidl): Don't throw when converting a detached buffer source (#12585)

The Web IDL conversion to `BufferSource` and similar types shouldn't
check whether the buffer is detached.

In the case of `TextDecoder`, our implementation would still throw after
the Web IDL conversions because we're creating a new `Uint8Array` from
the buffer source's buffer, which throws if it's detached. This change
also fixes this bug.

1 files changed, 13 insertions, 8 deletions

diff --git a/ext/web/08_text_encoding.js b/ext/web/08_text_encoding.js
index d3f6d45fb..d2922a6d4 100644
--- a/ext/web/08_text_encoding.js
+++ b/ext/web/08_text_encoding.js
@@ -105,14 +105,19 @@
       }
 
       try {
-        if (ArrayBufferIsView(input)) {
-          input = new Uint8Array(
-            input.buffer,
-            input.byteOffset,
-            input.byteLength,
-          );
-        } else {
-          input = new Uint8Array(input);
+        try {
+          if (ArrayBufferIsView(input)) {
+            input = new Uint8Array(
+              input.buffer,
+              input.byteOffset,
+              input.byteLength,
+            );
+          } else {
+            input = new Uint8Array(input);
+          }
+        } catch {
+          // If the buffer is detached, just create a new empty Uint8Array.
+          input = new Uint8Array();
         }
         if (input.buffer instanceof SharedArrayBuffer) {
           // We clone the data into a non-shared ArrayBuffer so we can pass it