1718750 - Reader Mode - Missing image after clicking on back and forward button

Status: NEW

(Toolkit :: Reader Mode, defect, P3)

Description

[Timea Zsoldos [:zstimi/tzsoldos], Desktop Release QA]

Attachment: before-and-after-clicking-back-forward.zip

Affected versions

• Fx 90.0b12
• Fx 91.0a1

Affected platforms

• Windows 8.1 x64
• Windows 10 x64
• Ubuntu 20.04 x64
• macOS 11

Steps to reproduce

1. Access the following webpage.
2. Click on the Enter Reader View button from the Location bar.
3. Navigate with Back/Forward buttons on the same tab where the reader view button was toggled.

Expected result

• The Reader view functionality is not affected, the page looks the same, all the images are displayed.

Actual result

• After click on back and forward buttons the images are missing from the page.

Regression range

• Here is the regression range.
• First bad: 2020-09-26 build ID: 20200926211645
• Last good: 2020-09-25 build ID: 20200925214743
• Pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=b7717ee20ba9d676a6f559efbcb45027db0003c6&tochange=cb8232ebe212789afead39e7709556cfe534324e

Additional notes

• This issue is reproduced only with certain pages.
• Attached screenshot to illustrate the difference.

Comment 1

[Marco Castelluccio [:marco]]

Is this a regression from bug 1667145?

Comment 2

[:Gijs (he/him)]

(In reply to Marco Castelluccio [:marco] from comment #1)

Is this a regression from bug 1667145?

Maybe, but it's unclear why that would have caused this issue, and it's now a 9-month old regression, and that change fixed other issues, so backing out isn't really an option. It's quite possible the source markup is different after moving in and out of reader mode... this would need someone to investigate further.