Expect TypeError when sealing non-empty TypedArrays

test/staging/built-ins/Object/seal/seal-variable-length-typed-arrays.js

@@ -15,6 +15,39 @@ for (let ctor of ctors) {
   const lengthTracking = new ctor(rab);
   const lengthTrackingWithOffset = new ctor(rab, 2 * ctor.BYTES_PER_ELEMENT);
 
+  assert.notSameValue(fixedLength.length, 0);
+  assert.notSameValue(fixedLengthWithOffset.length, 0);
+  assert.notSameValue(lengthTracking.length, 0);
+  assert.notSameValue(lengthTrackingWithOffset.length, 0);
+
+  // "Fixed length" TAs backed by RABs can shrink then re-grow.
+  assert.throws(TypeError, function() {
+    Object.seal(fixedLength);
+  });
+  assert.throws(TypeError, function() {
+    Object.seal(fixedLengthWithOffset);
+  });
+  assert.throws(TypeError, function() {
+    Object.seal(lengthTracking);
+  });
+  assert.throws(TypeError, function() {
+    Object.seal(lengthTrackingWithOffset);
+  });
+}
+
+for (let ctor of ctors) {
+  const rab = new ArrayBuffer(4 * ctor.BYTES_PER_ELEMENT, { maxByteLength: 8 * ctor.BYTES_PER_ELEMENT });
+  const rabZeroLength = new ArrayBuffer(0, { maxByteLength: 8 * ctor.BYTES_PER_ELEMENT });
+  const fixedLength = new ctor(rab, 0, 0);
+  const fixedLengthWithOffset = new ctor(rab, 2 * ctor.BYTES_PER_ELEMENT, 0);
+  const lengthTracking = new ctor(rabZeroLength);
+  const lengthTrackingWithOffset = new ctor(rab, 4 * ctor.BYTES_PER_ELEMENT);
+
+  assert.sameValue(fixedLength.length, 0);
+  assert.sameValue(fixedLengthWithOffset.length, 0);
+  assert.sameValue(lengthTracking.length, 0);
+  assert.sameValue(lengthTrackingWithOffset.length, 0);
+
   // "Fixed length" TAs backed by RABs can shrink then re-grow.
   assert.throws(TypeError, function() {
     Object.seal(fixedLength);
@@ -37,7 +70,43 @@ for (let ctor of ctors) {
   const lengthTracking = new ctor(gsab);
   const lengthTrackingWithOffset = new ctor(gsab, 2 * ctor.BYTES_PER_ELEMENT);
 
-  // Fixed length TAs backed by GSABs can't shrink, and so are allowed.
+  assert.notSameValue(fixedLength.length, 0);
+  assert.notSameValue(fixedLengthWithOffset.length, 0);
+  assert.notSameValue(lengthTracking.length, 0);
+  assert.notSameValue(lengthTrackingWithOffset.length, 0);
+
+  // Fixed length TAs backed by GSABs can't shrink, and so are allowed. TypedArray
+  // properties can't be redefined to non-configurable, so this still throws.
+  assert.throws(TypeError, function() {
+    Object.seal(fixedLength);
+  });
+  assert.throws(TypeError, function() {
+    Object.seal(fixedLengthWithOffset);
+  });
+  assert.throws(TypeError, function() {
+    Object.seal(lengthTracking);
+  });
+  assert.throws(TypeError, function() {
+    Object.seal(lengthTrackingWithOffset);
+  });
+}
+
+for (let ctor of ctors) {
+  const gsab = new SharedArrayBuffer(4 * ctor.BYTES_PER_ELEMENT, { maxByteLength: 8 * ctor.BYTES_PER_ELEMENT });
+  const gsabZeroLength = new SharedArrayBuffer(0, { maxByteLength: 8 * ctor.BYTES_PER_ELEMENT });
+  const fixedLength = new ctor(gsab, 0, 0);
+  const fixedLengthWithOffset = new ctor(gsab, 2 * ctor.BYTES_PER_ELEMENT, 0);
+  const lengthTracking = new ctor(gsabZeroLength);
+  const lengthTrackingWithOffset = new ctor(gsab, 4 * ctor.BYTES_PER_ELEMENT);
+
+  assert.sameValue(fixedLength.length, 0);
+  assert.sameValue(fixedLengthWithOffset.length, 0);
+  assert.sameValue(lengthTracking.length, 0);
+  assert.sameValue(lengthTrackingWithOffset.length, 0);
+
+  // Fixed zero-length TAs backed by GSABs can't shrink, and so are allowed. If
+  // the TypedArray is zero length, there's no attempt to redefine TypedArray
+  // properties.
   Object.seal(fixedLength);
   Object.seal(fixedLengthWithOffset);
   assert.throws(TypeError, function() {