G5.5.4 - routing differences between J3.10.3 and J4.0.4

[marktaylor46]

I tested this on a clean rocketlauncher installation of G5.4.37 and Helium

1. add two tags "testtag1" and "testtag2"
2. Filter on the blog articles and assign one tag or the other to each of the articles.
3. edit "blog" menu item options and set tag to "show"
4. Go to front end and click on "blog" and you get the list of blog articles each showing a tag
5. Click on "testtag1" against one of the articles and you follow a link of the form "/index.php/component/tags/tag/testtag1"
6. The list of articles for that tag correctly renders in the "default" outline
   
7. Update to G5.5.4 and Helium for G5.5.4
8. Look at blog on frontend again and Click on "testtag1" against one of the articles and you follow a link of the form "/index.php/component/tags/tag/testtag1"
9. The list of articles for that tag correctly renders in the "default" outline
10. Update to J4.0.4
11. Look at blog on frontend again and Click on "testtag1" against one of the articles and you follow a link of the form "/index.php/component/tags/tag/testtag1"
12. The list of articles for that tag does not show because this time the "home" outline is being used (which does not have a "page content" particle and therefore there is nowhere to render the list of articles). Also note that an error is showing in the browser console too
    
13. If you then add a "page content" particle to the "home" outline layout then the list does render on the frontend and the error in the console is no longer present

[mahagr]

It looks like Joomla 4 sets the menu item to home before onAfterRoute event where Joomla 3 didn't do that. This confuses the layout assign logic in Gantry and causes the wrong style to be used.

[mahagr]

It looks like in Joomla 4 SiteRouter::parseRawRoute() always sets Itemid where Joomla 3 didn't do that. This basically means that everything which doesn't have a route (or menu item) will be using the home menu item instead of no menu item.

[mahagr]

This behavior can be replicated with Cassiopeia, assign home menu item to it and set default to another template (such as Gantry). Joomla 3 used the other template, Joomla 4 uses the template style assigned to home menu item.

[morphinestyle]

Opened yesterday.
joomla/joomla-cms#37262