1203409 - TypeError: this._feedWriter is null when viewing RSS feed

Status: RESOLVED DUPLICATE of bug 1183296

(Firefox Graveyard :: RSS Discovery and Preview, defect)

Description

[Paul O'Shannessy [:zpao] (not bugmail, email directly)]

There's a type error trying to view an RSS feed in Nightly (43.0a1 (2015-09-09)). I can't repro in stable (40.0.3). I can repro this with multiple feeds.

Comment 1

[:Gijs (he/him)]

I can repro trivially on Nightly with e.g. http://feeds.bbci.co.uk/news/rss.xml?edition=uk . Works on 41, too.

I'm a little surprised this didn't set off automated tests. :-\

If nobody beats me to it, I'll look for a regression range tomorrow. This is broken on devedition from september 8 (which I happened to have lying around), too, and leads to not being able to view the feed contents at all. :-\

Comment 2

[:Gijs (he/him)]

Argh, I'm being silly. This is due to e10s, and a dupe of bug 1183296.

Comment 3

[James Teh [:Jamie]]

I'm running Firefox 45.0a1 (2015-11-24) and I get this with e10s disabled. I'm wondering whether this is a different issue given that bug 1183296 was fixed some time ago. Basically, I open a feed such as the one in comment 1 and I get no content, plus this in my console:

Use of Mutation Events is deprecated. Use MutationObserver instead. menulist.xml:240:16
NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS: [JavaScript Error: "aMenuitem is not defined" {file: "jar:file:///C:/Program%20Files%20(x86)/Nightly/browser/omni.ja!/components/FeedWriter.js" line: 639}]'[JavaScript Error: "aMenuitem is not defined" {file: "jar:file:///C:/Program%20Files%20(x86)/Nightly/browser/omni.ja!/components/FeedWriter.js" line: 639}]' when calling method: [nsIDOMGlobalPropertyInitializer::init] subscribe.js:13:0
TypeError: this._feedWriter is null
SH_writeContent()
 subscribe.js:17
onload()
 rss.xml:1
 subscribe.js:17:5

Comment 4

[:Gijs (he/him)]

(In reply to James Teh [:Jamie] from comment #3)
> I'm running Firefox 45.0a1 (2015-11-24) and I get this with e10s disabled.
> I'm wondering whether this is a different issue given that bug 1183296 was
> fixed some time ago. Basically, I open a feed such as the one in comment 1
> and I get no content, plus this in my console:
> 
> Use of Mutation Events is deprecated. Use MutationObserver instead.
> menulist.xml:240:16
> NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS: [JavaScript Error: "aMenuitem is
> not defined" {file:
> "jar:file:///C:/Program%20Files%20(x86)/Nightly/browser/omni.ja!/components/
> FeedWriter.js" line: 639}]'[JavaScript Error: "aMenuitem is not defined"
> {file:
> "jar:file:///C:/Program%20Files%20(x86)/Nightly/browser/omni.ja!/components/
> FeedWriter.js" line: 639}]' when calling method:
> [nsIDOMGlobalPropertyInitializer::init] subscribe.js:13:0
> TypeError: this._feedWriter is null
> SH_writeContent()
>  subscribe.js:17
> onload()
>  rss.xml:1
>  subscribe.js:17:5

Hey Jamie, can you reproduce this with a clean profile? ( https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles )

(if so, can you note on which feed you're seeing this? Thanks!)

Comment 5

[James Teh [:Jamie]]

For easy comparison, I was using the feed you referenced in comment 1; i.e. http://feeds.bbci.co.uk/news/rss.xml?edition=uk

Ug. No, I can't reproduce this with a clean profile, regardless of whether e10s is enabled or disabled. Any idea what pref might be breaking this? Otherwise, I'll have to go on a hunt at some point...

Comment 6

[James Teh [:Jamie]]

FWIW, I just tested my normal profile with add-ons disabled and still saw the problem. So it's down to a pref hunt.

Comment 7

[:Gijs (he/him)]

(In reply to James Teh [:Jamie] from comment #5)
> For easy comparison, I was using the feed you referenced in comment 1; i.e.
> http://feeds.bbci.co.uk/news/rss.xml?edition=uk
> 
> Ug. No, I can't reproduce this with a clean profile, regardless of whether
> e10s is enabled or disabled. Any idea what pref might be breaking this?
> Otherwise, I'll have to go on a hunt at some point...

It might be related to what you have specified Firefox should do with feeds and/or items with this mimetype (ie if you changed the default handler). Those aren't stored in prefs. Try moving mimeTypes.rdf out of the way in your profile folder (most easily found through about:support) and restarting, in your main profile. If that's it, I would be interested if you could either send me the whole rdf file or, if you prefer, narrow down what your feed opening things are (should be stored in that file; potentially also readable via about:preferences, and then the "Applications" tab).

Comment 8

[James Teh [:Jamie]]

Moving mimeTypes.rdf out of the way didn't help. :(

Comment 9

[James Teh [:Jamie]]

Got it. browser.feeds.handler.default was set to "client". A long time ago, I tried to set my feed handler to Thunderbird (and browser.feeds.handlers.application is pointing at thunderbird.exe). This doesn't work--Thunderbird can't handle this--but what's odd is that "Subscribe to this feed using" on feed pages doesn't reflect this; it's set to "Live Bookmarks".

Comment 10

[James Teh [:Jamie]]

To be clear, resetting browser.feeds.handler.default to the default of empty fixes the problem.