Instance properties of 'Response' issue in scriptlet and redirect

[piquark6046]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality in the uAssets issue tracker.
• This is not a support issue or a question. For support, questions, or help, visit /r/uBlockOrigin.
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue.
• The issue is not present after disabling uBO in the browser.
• I checked the documentation to understand that the issue I am reporting is not normal behavior.

I tried to reproduce the issue when...

• uBO is the only extension.
• uBO uses default lists and settings.
• using a new, unmodified browser profile.

Description

Screencast.from.2023-03-05.09-17-53.webm

Screencast.from.2023-03-05.09-16-58.webm

A specific URL where the issue occurs.

https://piquark6046.github.io/testpage/FetchResponse/

Steps to Reproduce

The step to reproduce is attached in the video.

piquark6046.github.io##+js(no-fetch-if, adsbygoogle.js)
||pagead2.googlesyndication.com/pagead/js/adsbygoogle.js$redirect=googlesyndication_adsbygoogle.js
@@||pagead2.googlesyndication.com/pagead/js/adsbygoogle.js

Expected behavior

Instance properties of Response return consistently like an unblocked request.

Actual behavior

Instance properties of Response return various values.

uBO version

1.47.2 (Firefox); 1.47.4 (Brave)

Browser name and version

Mozilla Firefox Developer Edition 111.0b8; Brave 1.48.171

Operating System and version

Ubuntu 22.10

[uBlock-user]

same as #2518 but this one is about fetch() ?

[piquark6046]

#2518 issue can be handled by creating a Proxy for only XMLHttpRequest.prototype.getResponseHeader and XMLHttpRequest.prototype.getAllResponseHeaders.

But, to resolve this, uBO handles Response.prototype.redirected, Response.prototype.url and Response.prototype.headers.

[uBlock-user]

Something to mind -

^ As long as above CORS policy remains in effect, browser will not allow data: stub resources from the extensions to load(resulting in a failed redirect), invariably causing different values to appear in the above case as well as in #2518

[gwarser]

Real use case where it is actually needed?

[piquark6046]

Real use case where it is actually needed?

• tsuvod.com AdguardTeam/AdguardFilters#144062 (In this case, they use XMLHttpRequest.prototype.getResponseHeader())

[piquark6046]

A real world case found.
In this case, AdGuard Browser Extension 4.1.53 is not affected.

It was a mistake.

[uBlock-user]

@piquark6046 now you can use piquark6046.github.io##+js(no-fetch-if, adsbygoogle.js, war:googlesyndication_adsbygoogle.js)

[gorhill]

Closing as fixed, in current dev build.

I didn't add Expires response header: it's an optional header and one of many others, I don't think it's a good for now to start arbitrarily adding response headers.