User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b3) Gecko/2008020514 Firefox/3.0b3 FireShot/0.32 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b3) Gecko/2008020514 Firefox/3.0b3 FireShot/0.32 Starting with Firefox 3 beta3, loading a local XML file via trusted chrome fails with the following error: "Access to restricted URI denied (NS_ERROR_DOM_BAD_URI)" Our Firefox extension has an XPCOM-based JavaScript component that creates an XML document object, then loads it with the contents of a local XML file using a valid local file URL string. Here's a stripped-down snippet of that part of the code: var domParser = CC["@mozilla.org/xmlextras/domparser;1"].createInstance(CI.nsIDOMParser); var domImpl = domParser.parseFromString("<?xml version='1.0' encoding='UTF-8' ?><dummy/>", "text/xml").implementation; var docObj = domImpl.doctype; var domTree = domImpl.createDocument("", "", null); domTree.async = false; domTree.load("file:///C:/d/y.xml"); The above code has been working fine for nearly 3 years, and also works fine in Firefox 3 beta2, as well as in all previous FF versions going back to at least 1.5. Reproducible: Always

See bug 397791. I have to ask: is there a reason not to just ParseFromStream on the file stream, or XMLHttpRequest, to start with? That would avoid creating the extra dummy document and so forth...

Bug 397791 comment 39 implies that this is WONTFIX.

Yes, the changes landed by bug 397791 do indeed appear to be the culprit, with these comments particularly relevant: https://bugzilla.mozilla.org/show_bug.cgi?id=397791#c20 https://bugzilla.mozilla.org/show_bug.cgi?id=397791#c25 And I very much agree with: https://bugzilla.mozilla.org/show_bug.cgi?id=397791#c37 https://bugzilla.mozilla.org/show_bug.cgi?id=397791#c38 Sigh.