[Bug 21929] New: named properties object should disallow definition of non-configurable properties

https://www.w3.org/Bugs/Public/show_bug.cgi?id=21929

            Bug ID: 21929
           Summary: named properties object should disallow definition of
                    non-configurable properties
    Classification: Unclassified
           Product: WebAppsWG
           Version: unspecified
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: WebIDL
          Assignee: cam@mcc.id.au
          Reporter: cam@mcc.id.au
        QA Contact: public-webapps-bugzilla@w3.org
                CC: mike@w3.org, public-script-coord@w3.org

The named properties object exposes named properties as configurable data
properties.  There is no special [[DefineOwnProperty]], so we can still define
our own on the object.  [[DefineOwnProperty]] can successfully set an own
property on the object, although named properties will still shadow them when
you get them.  This allows [[DefineOwnProperty]] to set a non-configurable
property, which then can be exposed as configurable if a named property starts
existing with the same name later.  This breaks an invariant on
[[Configurable]].  We could have [[DefineOwnProperty]] force [[Configurable]] =
true, just like [[DefineOwnProperty]] for platform objects implementing
interfaces that support named properties.  Or we could disallow expandos on the
named properties object.

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Received on Sunday, 5 May 2013 02:31:08 UTC