2022643 - Allow UTF-8 BOM at the beginning of a pref file

Status: RESOLVED FIXED

(Core :: Preferences: Backend, defect)

Description

[Greg Stoll :gstoll]

The telemetry data we gathered in bug 2004956 indicates that users have prefs files with a UTF-8 BOM that the prefs parser does not handle correctly. We can just skip over these bytes and parse the file as normal (in our sample data, all of the files would have parsed correctly if we had done this)

Comment 1

[Greg Stoll :gstoll]

Attachment: Bug 2022643 - skip UTF-8 BOM when parsing prefs files r=glandium!

Our telemetry data indicates that this is pretty common. (in an admittedly
small sample) I will continue monitoring the failure rate after this goes
in to see if we get any improvements in Nightly.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/bb7797b5c2c4
https://hg.mozilla.org/integration/autoland/rev/25cf3ca80d91
skip UTF-8 BOM when parsing prefs files r=glandium

Comment 3

[amarc]

https://hg.mozilla.org/mozilla-central/rev/25cf3ca80d91

Comment 4

[Phabricator Automation]

firefox-beta Uplift Approval Request

• User impact if declined/Reason for urgency: simple fix that could significantly reduce the number of users for which we fail to parse prefs files (fingers crossed!)
• Code covered by automated testing?: yes
• Fix verified in Nightly?: no
• Needs manual QE testing?: no
• Steps to reproduce for manual QE testing: n/a
• Risk associated with taking this patch: low
• Explanation of risk level: just skip a few bytes at the beginning of a prefs file if it's a UTF8 BOM
• String changes made/needed?: no
• Is Android affected?: yes

Comment 5

[Greg Stoll :gstoll]

Attachment: Bug 2022643 - skip UTF-8 BOM when parsing prefs files

Our telemetry data indicates that this is pretty common. (in an admittedly
small sample) I will continue monitoring the failure rate after this goes
in to see if we get any improvements in Nightly.

Original Revision: https://phabricator.services.mozilla.com/D287210

Comment 6

[Phabricator Automation]

firefox-esr140 Uplift Approval Request

• User impact if declined/Reason for urgency: simple fix that could significantly reduce the number of users for which we fail to parse prefs files (fingers crossed!)
• Code covered by automated testing?: yes
• Fix verified in Nightly?: no
• Needs manual QE testing?: no
• Steps to reproduce for manual QE testing: n/a
• Risk associated with taking this patch: low
• Explanation of risk level: just skip a few bytes at the beginning of a prefs file if it's a UTF8 BOM
• String changes made/needed?: no
• Is Android affected?: yes

Comment 7

[Greg Stoll :gstoll]

Attachment: Bug 2022643 - skip UTF-8 BOM when parsing prefs files

Our telemetry data indicates that this is pretty common. (in an admittedly
small sample) I will continue monitoring the failure rate after this goes
in to see if we get any improvements in Nightly.

Original Revision: https://phabricator.services.mozilla.com/D287210

Comment 8

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/59799b7b228b
https://hg.mozilla.org/releases/mozilla-beta/rev/3fb327191815

Comment 9

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-esr140/rev/f8e741e46f46