1675062 - A snippet is wrongly displayed on the first New Tab to be opened after disabling Snippets

Status: VERIFIED FIXED

(Firefox :: Messaging System, defect)

Description

[Maria Heres, inactive, contact Ecosystem QA]

Attachment: snippet displayed.gif

[Affected versions]:

• Firefox Nightly 84.0a1 (Build ID: 20201103095421)

[Affected Platforms]:

• Windows 10
• Linux Mint 20
• macOS 10.15

[Prerequisites]:

• Have Firefox Nightly 84.0a1 installed and open.
• Have snippets enabled.

[Steps to reproduce]:

1. Open a new tab to observe that snippets are displayed.
2. Navigate to “about:preferences#home” and untick the “Snippets” checkbox.
3. Open a new tab and observe the behavior.

[Expected result]:

• A snippet is NOT displayed on a new tab opened after disabling them.

[Actual result]:

• A snippet is displayed on the first new tab opened.

[Regression Info]:

• This seems to be a regression as it isn’t reproducible on Release or Beta.
• Using mozregression:
  Last good revision: a94f3815ca4a816c73f7e09b508176f7a719381f
  First bad revision: 0a719a2effaa979914f9270b7e59966d43333025
  Pushlog:
  https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=a94f3815ca4a816c73f7e09b508176f7a719381f&tochange=0a719a2effaa979914f9270b7e59966d43333025
• The cause might be Bug 1614465 .

[Notes]:

• The snippets on new tabs opened before disabling Snippets will also remain displayed.
• Attached is a recording of the issue.

Comment 1

[Mike Conley (:mconley) (:⚙️)]

I can reproduce. It seems that the preloaded about:newtab isn't getting the snippet state update.

Comment 2

[Mike Conley (:mconley) (:⚙️)]

The problem is here: https://searchfox.org/mozilla-central/rev/c938c7416c633639a5c8ce4412be586eefb48005/browser/components/newtab/lib/ASRouter.jsm#594-601

This code is expecting that _updateMessageProviders returns an array of message IDs. However, it actually returns an array of provider IDs that have been disabled. This ultimately gets sent do the child with the “ClearMessages” message, but that ID (being for a provider and not a message) is then ignored.

Comment 3

[Mike Conley (:mconley) (:⚙️)]

Attachment: Bug 1675062 - Re-add capability to notify content about cleared ASRouter providers. r?andreio!

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4aad474fb048
Re-add capability to notify content about cleared ASRouter providers. r=andreio

Comment 5

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/4aad474fb048

Comment 6

[Maria Heres, inactive, contact Ecosystem QA]

I have verified this issue is no longer reproducible on the latest Nightly 84.0a1 (Build ID: 20201108212832) on Windows 10, macOS 10.15.7, Mint 20. After Snippets are disabled they are removed from already open tabs and are not displayed for any new tabs.