Redirect Loop with multiple spaces in the url

[rolandfarkasCOM]

Bug Description

A redirect loop is caused when more than one spaces are in the url.

Expected Behaviour

Page to work normally

Steps to Reproduce

defeated-leopard.jurassic.ninja/?test=test+this+out+as+it+breaks+your+site

I have uninstalled Jetpack, installed AMP, enabled standard mode, selected a static homepage, and changed the permalink settings to Post Name.

So by the looks of it, a combination of the above settings is the cause.

Screenshots

N/A

Additional context

• WordPress version: Latest
• Plugin version: Latest
• Gutenberg plugin version (if applicable):
• AMP plugin template mode: Standard
• PHP version: 7.4,8.0
• OS: UBUNTU
• Browser: All
• Device: All

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Acceptance criteria

Implementation brief

QA testing instructions

Demo

Changelog entry

[milindmore22]

I am able to reproduce this issue with Static Homepage and post name permalink structure.

[westonruter]

I can reproduce the issue as well, but only when a static front page is selected. It also happens only when the AMP plugin is active alone.

[westonruter]

I've traced the issue down to a behavior where remove_query_arg() is normalizing URLs to use + for spaces instead of %20:

wp> remove_query_arg('amp', '/?test=one+two+three')
=> string(20) "/?test=one+two+three"
wp> remove_query_arg('amp', '/?test=one%20two%20three')
=> string(20) "/?test=one+two+three"

In contrast, redirect_canonical() is normalizing query strings to use %20 instead of + for spaces, by means of parse_str() plus rawurlencode_deep():

parse_str('test=one+two+three', $parsed_query); echo rawurlencode_deep($parsed_query['test']);
>> one%20two%20three
parse_str('test=one%20two%20three', $parsed_query); echo rawurlencode_deep($parsed_query['test']);
>> one%20two%20three

In this way, \AmpProject\AmpWP\PairedRouting::redirect_extraneous_paired_endpoint() is causing a redirect with query parameters including + but then redirect_canonical() is redirecting to use %20.

[westonruter]

I've created the fix in #6494.

[rolandfarkasCOM]

Thanks @westonruter & @milindmore22 hopefully an update will be available soon.

[westonruter]

To be closed when the PR is merged.

We'll give you a prerelease build to use while waiting for 2.1.4.

[rolandfarkasCOM]

Thank you 👍🙏

[westonruter]

@rolandfarkasCOM Please use the 2.1.x production build linked from the Development Builds wiki page.

[westonruter]

QA Passed

After having set the template mode to Standard, setting the homepage to a static page, and setting the permalink structure to post name:

Before, going to: https://wordpress-stable.lndo.site/?test=test+this+out+as+it+breaks+your+site

After, no infinite redirect:

[rolandfarkasCOM]

Thanks for the help @westonruter it is very much appreciated!