Non-Existent Images serving Placeholder Image return 200 Status instead of 404 Status affecting CDNs/Edge Servers/Browser Cache

[AndresInSpace]

Preconditions and environment

M2 2.4.7-p2
Add assets for default placeholder images.
Set through configuration/admin panel.
Ensure placeholders are used if image does not exist.

Steps to reproduce

make a request for a bogus image path you know will fail and return placeholder image

Expected result

Placeholder response and 404 status code
edge caches/image cdns/browsers/etc are caching image correctly based on 404 status code resulting in an extremely short cache expiration time set and for image delivery networks the master image source is not considered set.

Actual result

Placeholder response and 200 status code
edge caches/image cdns/browsers/etc are caching placeholder image incorrectly based on 200 status code resulting in (usually) very long cache expiration times set and for image delivery networks the master image source is now considered set.

Additional information

A 404 status code should be set when an image request is not found, but response is sent using placeholder data.

Live Example:
curl https://i4.ytimg.com -i
You will see response code is 404, but browser still utilizes response data to render the image based on standards. https://html.spec.whatwg.org/#images-processing-model

I believe S2 status is warranted since these are 404 placeholders, ie non-critical, and we have to employ a workaround to ensure we are not incurring extra costs from our CDNs (ie monitor and purge master source assets in CDNs being created from fake 200 placeholder responses).

Release note

No response

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

Hi @AndresInSpace. Thank you for your report.
To speed up processing of this issue, make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce. To deploy vanilla Magento instance on our environment, Add a comment to the issue:

• @magento give me 2.4-develop instance - upcoming 2.4.x release
• For more details, review the Magento Contributor Assistant documentation.
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[AndresInSpace]