TASK: Remove unused Fusion\Core\ParserInterface

[mhsdesign]

The Fusion\Core\ParserInterface is removed as it could not be used to implement an alternative Fusion parser. The removal of the interface will allow to improve the interface of the parser in future.

Upgrade instructions

If you must access the Fusion parser directly - then dont inject it by using the Fusion\Core\ParserInterface but inject or instantiate Fusion\Core\Parser.
The recommended way to interact with Fusion is via the FusionView

Review instructions

Checklist

• Code follows the PSR-2 coding style
• Tests have been created, run and adjusted as needed
• The PR is created against the lowest maintained branch
• Reviewer - PR Title is brief but complete and starts with FEATURE|TASK|BUGFIX
• Reviewer - The first section explains the change briefly for change-logs
• Reviewer - Breaking Changes are marked with !!! and have upgrade-instructions

[kdambekalns]

Useless things must go. 🤷‍♂️

[mhsdesign]

fyi - option B would be to actually use this interface by injecting the ParserInterface via di instead of using new

[kdambekalns]

fyi - option B would be to actually use this interface by injecting the ParserInterface via di instead of using new

Thus offering an extension point we do not even remotely expect to be used. 🤔 Sounds weird.

[mhsdesign]

yes - and one can always use aop ^^

[mficzel]

Remove stuff that serves no purpose

[mficzel]

@mhsdesign can you upgrade the message of the pr to a descriptive text that can be used in the release notes. The current text can be moved to the release notes section that is nut included in the release notes

Suggestion:

The Fusion\Core\ParserInterface is removed as it could not be used to implement an alternative Fusion parser. The removal of the interface will allow to improve the interface of the parser in future.

[mhsdesign]

yes ;)

Initial PR message:

While working on #3497

i asked myself already:
speaking of interface - the parser uses [...] the parser interface, which seems quite useless as it contains only the method parse. i looked up usages of the parser interface and found none... should it be kicked?

but back then the consent was:

Martin:
The parser interface declares that the method parse is the only thing code outside of the parser should rely on.
It is good practice to declare such interfaces explicitly especially as it allows to differentiale breaking from non breaking changes by looking wether interfaces are modified.

Now the question came up again with #3839
Do we really need the ParserInterface?

We re-discussed this matter and as there are still 0 references to ParserInterface (except of course the Parser which implements it) it is useless.

A few opinions:

Karsten:
Then maybe drop it (the interface, not the @api), before someone notices? 🙈

Christian:
Given that it's a useless interface I doubt anyone has really implemented it, so from my side I would be fine with this technically breaking change. I am SURE there is a project where someone imlpemented the interface but never checked if it works and it breaks, but weeeeeell......

Martin:
Strange but I also see no point in keeping it. Even when we hacked the first version of afx into fusion we used aop and not that.
[...]
Would prefer to drop the interface in 8.2 and note it in the release notes as removal of an unusable extension point