Bug 10038 – REGRESSION: Length of navigator.mimeTypes collection returns number of installed plugins, not number of registered mime types

• Component: DOM
• Status: RESOLVED FIXED

[Brian Ellis]

(This bug is a regression from Safari 419.3.)

The "navigator.mimeTypes" collection is supposed to store a list of all registered MIME types for which the browser has a handler.  In the nightly WebKit builds, however, querying the length of this collection in the WebKit nightly returns the length of the navigator.plugins collection instead.

Since this is typically much less than the number of registered MIME types, a script looping over all the registered types will only access the first n of them, where n is the number of installed plugins.  Attempting to access out-of-bounds indices that are within the bounds of the actual array does work as expected:

>> navigator.mimeTypes.length
<< 14
>> navigator.mimeTypes[70]
<< "audio/x-aiff"

which leads me to believe that it's simply the wrong length being returned.

REDUCTION:

The URL for this bug points to a simple reduction of the bug, using Safari's "Help > Installed Plug-ins" page is a template.  Scroll to the bottom to see the incorrect behavior.

As this will cripple any script attempting to loop over all the installed plugins (as Apple's own plugin example does), this bug is considered a critical one.

[Brian Ellis]

Created attachment 9588 [details]
The bug reduction linked to in the URL, in case a local copy is preferable.

[Alexey Proskuryakov]

Regression->P1

[Alexey Proskuryakov]

Created attachment 9604 [details]
proposed fix

[Darin Adler]

Comment on attachment 9604 [details]
proposed fix

r=me

[Alexey Proskuryakov]

Committed revision 15573.