Bug(s) in strip category base option

[jrfnl]

I haven't figured out completely yet what's going on and where it's going wrong, but there is definitely a (or several) bugs in the whole strip category base option handling.

Tested and observed on WP 3.5.2, virgin WP install with virgin WP SEO.
Theme TwentyTwelve, no other plugins active [note: no WPML!], but the Debug Bar with some add-ons.

Issue 1:

1. Turn on category base
2. Go to a category page => 404

Seems that this happens because the rewrite rules get deleted, but haven't been renewed yet. Saving Settings->Permalinks solves this.

Issue 2:

Next, once you have gotten rid of the 404.

1. Turn off category base
2. Go to a page where the category base was off => expected behaviour 'reverse redirect', i.e. redirect to category/term, observed behaviour: 404

It seems that the plugin does not account for users turning the option off and outside links still pointing to the category-base-stripped version of the url.

Issue 3:

1. Manually add the word category to the url in the address bar & load => page redirects back to the category base stripped url resulting in 404

Similarly, it seems that this happens because the rewrite rules get deleted, but not renewed.

I haven't tested this in other WP versions, results may vary ;-)

Relevant files involved AFAICS:

• wp-seo.php
• inc/class-rewrite.php (only gets loaded when option turned, that might be part of the problem)
• admin/class-admin.php

Issue #87 and issue #72 might be related to these bugs.

We might also want to have a look at the code of WP No Category Base - WPML compatible for inspiration.

Forum threads mentioning this (recurring or similar) issue - quite a large number can found, going back at least two years, amongst which:

• http://wordpress.org/support/topic/remove-category-from-url-wpml-bug
• http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-404-error-category-strip-permalink-after-new-update-1281
• http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-remove-category-base
• http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-category-xml-404-blog-slug-multisite
• http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-strip-category-base-not-working-in-24
• http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-categories-sitemap-return-404-errors
• http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-stripping-category-base-fails-in-upgrade-to-wp-341
• http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-category-and-tags-dont-work-anymore/
• http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-permalinks-category-base-problem
  "For bugfixing: I noticed it breakes every time agan when I edit the description of a category."
• http://wordpress.org/support/topic/category-and-tag-links-redirect-to-404-page-since-wp-341-upgrade
• http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-strip-category-feature-causing-404-errors
• http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-removing-category-base-results-in-selective-404-results

[Rarst]

The feature is planned to have major rewrite, see #2207. Closing older issues on topic as they will probably be better served by new implementation.