Firefox, Google Drive vs. NS_ERROR_INTERCEPTION_FAILED
This is a geeky English entry. Kind of making notes for everyone.
Problem space
The original problem is that Google Drive in Firefox (almost irrelevant which version but this one's Nightly) cannot load "Details" and "Activity" sidebar content, instead I get "Couldn't load details. Try again." instead of the content.
The problem seems deterministic usually, so it does not load whether you sacrifice a black rooster on full moon, dancing naked in the middle of the enchanted forest or not; however it may happen that it just loads, once, or a few times, then it's gone again.
When I have tried to connect it to addons it resulted nothing: yes, it is related to the fact that my Firefox is packed with antispam extensions but no, it is not caused by "any" of those, at least I can open a new session, activate all extensions and the side panel would work just fine.
Now that I'm closer to the secret I should probably start removing them in reverse order to actually pinpoint it to one or a few but… the real problem seems to be something else.
Looking for hints
I'll not detail you my search, but the result was that the problem is not present
- in anonymouse mode
- without extensions
- in other browser (namely chromium, but it uses a different class of extensions anyway)
- in a completely new browser session with the same set of extensions!
The last made it very confusing. So I started looking around and found that maybe it is related to the NS_ERROR_INTERCEPTION_FAILED error in the Firefox console. This is a very useful error message if the purpose is to maximise confusion and minimise any chance to fix any problems, since the error message means that there was an unspecified problem with an unspecified part of an unspecified extension (or maybe even Firefox core) when it have tried to intercept (hook) the page loading. Awfully helpful (awhelpful? helpawful?).
So I started to google it (look, ma, it's a verb now!), and found almost nothing. But one page was kind of suspicious, namely an error report for the venerated NoScript from 2022, which described a pretty convoluted problem they have fixed there:
Fetch requests initiated by service workers (such as those used by Spotify to cache album covers locally) were not reported in the UI: it's something quite tricky, because service workers have no associated tab, hence NoScript would need to keep track of all the tab containing documents which may be using the service worker and report back to all of them. Therefore you could not notice that scdn.com (set to DEFAULT because you use the full address UI listing and surgically enabled only https://open.scdn.co) was the destination of fetch requests to retrieve images, which were blocked because you unchecked the "fetch" capability from the DEFAULT preset.
So, hmm. Giorgio Maone (PBUH) said that they had a problem with service workers not being able to follow stuff scattered throughout plenty of tabs? So, let me see, what happens if I simply create a clean session in the same configured firefox (I am using Conex so I can create session groups) and open Drive from there?
Yep, damn, it worked. It seems to work.
Solution or workaround
While I don't have time to research this now further I can say that the fix is simple: do not open multiple tabs for the same site (Google Drive) in the same session (where the service workers are shared, I presume), and it will work, no "Couldn't load details. Try again." anymore. Probably this could be caused and fixed by fiddling with the specific settings of various spam blocker extensions (my guess would be uMatrix and uBlock Origin but there are other strong contenders), but right now I'm okay with opening a separate session for Drive and let it rest. And how I wish the error message would be more specific, at least point to the extension (or hook) which fails, or even better tell me about the specific error how what is failing.
Hope it helps. Someone. Index this, Google, thxbye.