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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - ES6: Make Array.prototype.splice implement step 8 of its spec."
href="https://bugs.webkit.org/show_bug.cgi?id=163417">163417</a>
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<th>Summary</th>
<td>ES6: Make Array.prototype.splice implement step 8 of its spec.
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<th>Classification</th>
<td>Unclassified
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<th>Product</th>
<td>WebKit
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<th>Version</th>
<td>WebKit Local Build
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<th>Hardware</th>
<td>Unspecified
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<th>OS</th>
<td>Unspecified
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>Normal
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<th>Priority</th>
<td>P2
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<th>Component</th>
<td>JavaScriptCore
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<th>Assignee</th>
<td>webkit-unassigned@lists.webkit.org
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<th>Reporter</th>
<td>mark.lam@apple.com
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<pre>Step 8 of the Array.prototype.splice spec (<a href="https://tc39.github.io/ecma262/#sec-array.prototype.splice">https://tc39.github.io/ecma262/#sec-array.prototype.splice</a>) states that we should throw a TypeError if the spliced array's length will exceed 2^53-1. This is gated on the JSArray getLength() convenience function being updated to return a length value that is greater than 32-bits. This issue is only a compliance issue in a contrived example, e.g.
var maxLength = (2 ** 53) - 1;
Array.prototype.splice.call({ length: maxLength }, maxLength, 0, 1, 2, 3);
In real world code, the JSC runtime prevents us from creating arrays with a length that exceeds UINT_MAX. We're also bounded on the number of args that we pass to Array.prototype.splice. As a result, we can never splice together an array that gets anywhere near 2^53-1. We'll get an OutOfMemoryError long before then.</pre>
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