[Webkit-unassigned] [Bug 146047] New: REGRESSION: Error's "column" property should not be readonly

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=146047

            Bug ID: 146047
           Summary: REGRESSION: Error's "column" property should not be
                    readonly
    Classification: Unclassified
           Product: WebKit
           Version: 528+ (Nightly build)
          Hardware: Unspecified
                OS: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: JavaScriptCore
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: joepeck at webkit.org
                CC: mark.lam at apple.com,
                    webkit-bug-importer at group.apple.com

* SUMMARY
Error's "column" property should not be readonly. This used to work in Safari 8, but now fails in ToT WebKit.

* TEST
<script>
"use strict";
var error = new Error('My Error Message');
error.lineNumber = 1;
error.column = 2; // Should not trigger a TypeError.
console.log("SUCCESS", error);
</script>

* STEPS TO REPRODUCE
1. Open attached test case
  => get an error attempting to set error.column, used to work
  => [Error] TypeError: Attempted to assign to readonly property.

* NOTES
- Firefox and Chrome do not throw an error
- This is done in the Esprima JS Library, so there may also be other libraries that do this and expect it to work

* DESCRIPTORS
> Object.getOwnPropertyDescriptor(error, "column")
< {value: 22, writable: false, enumerable: true, configurable: false} = $2
> Object.getOwnPropertyDescriptor(error, "lineNumber")
< {value: 1, writable: true, enumerable: true, configurable: true} = $3

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