1689775 - [Tb 86.0b1 regression] "Start the week on" (first day of week) pref is no longer honored at startup in mini-month

Status: VERIFIED FIXED

(Calendar :: Calendar Frontend, defect, P1)

Description

[Ronan Jouchet]

Steps to reproduce

• In Preferences / Calendar, set Start the week on to Monday
• Restart Thunderbird
• Look at the Mini-Month

Expected behavior

Mini-Month first day of the week should be Monday, as requested

Actual behavior

• Mini-Month first day of the week is Sunday
• If flipping the pref to anything then back to Monday, then Mini-Month temporarily renders correctly with Monday as first day...
  • ... but then behaves incorrectly again after a restart.

Information

• 86.0b1-20210128005905
  • Bug is a regression, pref used to be honored in 85.0b3
• Linux x86_64
• Available for more debug info, feel free to ask

Comment 1

[Magnus Melin [:mkmelin]]

Confirmed.

Comment 3

[Ronan Jouchet]

Confirming bug remains reproducible in 86.0beta2.

Comment 4

[Geoff Lankow (:darktrojan)]

Attachment: Bug 1689775 - Stop using preferences service observers to update mini-month display. r?mkmelin

This bug was caused by the observer notification happening before the lazy preference getter's cached value updated.

Instead of having a static lazy preference getter I've decided to have one per instance which does the updating of the instance itself.
The cost is minimal plus I'm removing the cost of the preference service observer.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/comm-central/rev/31651ff1ee5e
Stop using preferences service observers to update mini-month display. r=mkmelin

Comment 6

[Geoff Lankow (:darktrojan)]

Comment on attachment 9201985 [details]
Bug 1689775 - Stop using preferences service observers to update mini-month display. r?mkmelin

[Approval Request Comment]
Regression caused by (bug #): bug 1660692
User impact if declined: today pane calendar starts on the wrong day of the week
Testing completed (on c-c, etc.): landed 2 days ago
Risk to taking this patch (and alternatives if risky): no

Comment 7

[Wayne Mery (:wsmwk)]

Comment on attachment 9201985 [details]
Bug 1689775 - Stop using preferences service observers to update mini-month display. r?mkmelin

[Triage Comment]
Approved for beta

Comment 8

[Rob Lemley [:rjl]]

Thunderbird 86.0b3:
https://hg.mozilla.org/releases/comm-beta/rev/c0b91eebe4da

Comment 9

[WaltS48 [:walts48]]

TB 86.0b3 on Windows 10