Handle normal anchor links as expected

[sgiehl]

Description:

Normal anchor links currently fully break the application, as Matomo tries to interpret those values as parsable URL. This results in an empty page being loaded.

This PR aims to change that behaviour. Before trying to use any hash value as report URL the system will now check if the hash value looks like an anchor and if an element with an according id (or a link with a name attribute) exists. If that is the case the according element will be scrolled into view. The hash part of the URL will then be reset to the previous value.

fixes #23060

Review

• Functional review done
• Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• Documentation added if needed
• Existing documentation updated if needed

[mneudert]

Can this have some really ugly side effects? 🤔

For example the inline link for image tracking in the javascript tracking code generator:

matomo/plugins/CoreAdminHome/vue/src/JsTrackingCodeGenerator/JsTrackingCodeGenerator.vue

Lines 213 to 219 in 9a3ef94

	jsTrackingIntro4a() {
	return translate(
	'CoreAdminHome_JSTrackingIntro4',
	'<a href="#image-tracking-link">',
	'</a>',
	);
	},

The actual section links at the top are always going to #/section, not just #section. That one inline link now goes to the actual anchor, and if you have any other section in your hash, like #/react, the change back to the previous hash will also trigger a scroll to the previous section.

Now this is a simple one to fix (just update the inline anchor link), but maybe there are more places that would actually break when cycling hashes?

[sgiehl]

Would it make sense to check if the previous hash was something containing = or & and only do it in that case? 🤔

[mneudert]

Ideally I would say we replace the skip-to-content link with a pure JS implementation: focus the main element, scroll that element into view, don't use any hash manipulation.

If that is sufficient for accessibility we wouldn't need to change any hashes around 🤔