1899184 - Firefox is sometimes unable to load/render previously cached images

Status: UNCONFIRMED

(Fenix :: General, defect)

Description

[michael]

Attachment: Have used this file to reproduce the problem

Firefox for Android

Steps to reproduce:

1. Load Discourse page containing avatar images
2. Wait
3. Reload page

Actual results:

sometimes, the browser is unable to load the avatar image and reports "Could not load the image".

Expected results:

Normal operation.

A more detailed description of the situation is below, which is an abridged version of a more detailed report on meta.discourse.org (https://meta.discourse.org/t/309597?u=supermathie) that contains inline screenshots:

<<<
We are investigating what seems to be a Firefox bug relating to avatars being cached on disk and then retrieved by a later request.

The way this problem manifests is missing avatars where one would normally be present.

While inspecting the DOM using the devtools, Firefox reports "Could not load the image"

It's never on initial requests that this fails - it's always only happened on subsequent requests that would load the image from cache.

Reloading the page sometimes triggers Firefox to load the image properly.

We know that:

… the problem is not specific to the Discourse application itself. We have reproduced the problem with a static HTML page containing only links to avatars:

… disabling http3 in Firefox does not resolve the problem

… flushing the browser cache causes the images to properly load the next time

… end users have reported this problem on desktop and mobile

We suspect that:

… this has something to do with the image being loaded after a redirect

Certain of our hosting environments have a "redirect chaser" installed that causes a request to the the original URL to return the image itself instead of a redirect to the image. I do not believe anyone has experienced this problem in those environments.

The attached "images.html" file was used to reproduce the problem outside of Discourse.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Fenix::General' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[michael]

FYI we have changed our CDN configuration to work around this bug (a lambda being run on the initial request chases the redirect and returns the response directly rather than sending the redirect to the client) and you should not expect to be able to reproduce the problem with our current configuration.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:amejia, could you have a look please?

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