Summary of Changes

Removes the deprecated static singleton accessors that the dependency injection container replaced in 4.x: Pathway::getInstance(), Session::getInstance(), Cache::getInstance() and CacheController::getInstance(), together with CacheController::addIncludePath() and the JCacheController* include-path lookup that only served it. The static $instances cache on Pathway had no other user and goes with it.

Nothing in core calls any of these. Router::getInstance() is deliberately left out: it is still called by the deprecated getRouter() methods of the application classes and belongs to their removal.

Testing Instructions

1. Code review: grep -rn "Pathway::getInstance\|Session::getInstance\|Cache::getInstance\|CacheController::getInstance\|CacheController::addIncludePath" libraries administrator components plugins modules api finds nothing.
2. Apply the patch. Site: open an article inside a category with breadcrumbs enabled; the breadcrumbs module renders (Pathway).
3. Site and administrator: log in, submit a form, log out (Session, form tokens).
4. Administrator: System > Global Configuration > System, set System Cache to "ON - Conservative caching", save. Load a site page twice; then System > Clear Cache lists the cached groups and clears them (Cache, CacheController through the factory).
5. Enable "System - Page Cache", load a site page twice as a guest, disable it again.
6. Turn debug on and check no PHP notice, warning or deprecation appears during steps 2 to 5.

Actual result BEFORE applying this Pull Request

Everything works; the five static methods exist but nothing in core calls them.

Expected result AFTER applying this Pull Request

Everything works the same. The five methods are gone.

Link to documentations

• No documentation changes for guide.joomla.org needed
• Pull Request link for manual.joomla.org: joomla/Manual#715