1549086 - Page zoom for about: pages stores page zoom settings keyed on URL including hash/querystring (leading to unexpected page zoom changes when reloading or navigating to the same page with a hash appended)

Status: NEW

(Toolkit :: Preferences, defect, P3)

Comment 1

[Alice0775 White]

Reproducible : always

Steps To Reproduce:

1. Open about:preferences
2. Zoom In
3. Click on Home
   --- observe, the zoom level is as expected
4. Reload (f5)
   --- observe, the zoom level is reset --- BUG

optionally
5. Open about:preferences in new tab
--- observe, the zoom level is as expected
6. Click on General, Home
--- observe, the zoom level is as expected
7. Reload (f5)
--- observe, the zoom level is reset --- BUG

Actual Results:
Reloading will reset zoom level on about:preferences#something

Expected Results:
The zoom level should persist

Comment 2

[:Gijs (he/him)]

We store site-specific prefs like zoom in the contentprefservice. It normalizes URLs in https://searchfox.org/mozilla-central/rev/b2015fdd464f598d645342614593d4ebda922d95/toolkit/components/contentprefs/ContentPrefService2.jsm#63-97 . For reasons I do not understand (but likely historical), the APIs all take strings instead of URIs, and as a result we have to reparse the URI.

This parsing uses the hostname for "normal" URLs, and something similar for file URLs and other nsIURLs. However, about: URLs are none of those, and we hit the fallback at:

https://searchfox.org/mozilla-central/rev/b2015fdd464f598d645342614593d4ebda922d95/toolkit/components/contentprefs/ContentPrefService2.jsm#92

The minimal fix here is probably to update that to specIgnoringRef. Ideally we should have a test, too.