Block Hooks: Add new hooked_block filter

[ockham]

In [57354] (#5835), a new hooked_block_{$block_type} filter was introduced that allowed extenders to specify attributes and inner blocks for hooked blocks.

@swissspidy pointed out that for filters with a dynamic name portion like this, it is customary to have a "non-dynamic" counterpart filter (i.e. hooked_block, in this case).

There are a few concerns around the implications for the function signatures for each filter. We can discuss them here (or on a PR that implements this feature) and decide how to proceed.

Trac ticket: https://core.trac.wordpress.org/ticket/60574

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[ockham]

To quote my own concerns:

So the signature for the non-dynamic version would have to be something like

apply_filters( 'hooked_block', $parsed_hooked_block, $hooked_block_type, $relative_position, $parsed_anchor_block, $context )

which then raises the question if we also need to adjust the dynamic version to include the type (for consistency)?

apply_filters( "hooked_block_{$hooked_block_type}", $parsed_hooked_block, $hooked_block_type, $relative_position, $parsed_anchor_block, $context )

Note that this duplicates $hooked_block_type (which is already present in the filter name) in a somewhat ugly way; plus given the way that filters work, that arg ends up in the position after $parsed_hooked_block, which is also a bit awkward.

[github-actions]

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[swissspidy]

Note that this duplicates $hooked_block_type (which is already present in the filter name)

"Duplicating" the variable again is the whole point of it :)

Just left this as a comment on the ticket as well, but about moving $hooked_block_type to the end of the arguments list? Would that be less awkward?

[ockham]

Just left this as a comment on the ticket as well, but about moving $hooked_block_type to the end of the arguments list? Would that be less awkward?

Given the choice, I think I'd swallow the pill and would put it in the second position (i.e. after $parsed_hooked_block, as per the current diff).

The chief reason being that substituting for parameters, it's at least somewhat natural to read:

..., $hooked_block_type, $relative_position, $parsed_anchor_block, ...

becomes e.g.

..., 'ockham/like-button`, `after`, `core/post-content`,...

which does exactly what it says: It inserts a Like Button block after the Post Content block.

(Furthermore, we have a convention of sorts that $context is the last argument in Block Hooks related functions and filters, e.g. in the hooked_block_types filter (introduced in 6.4).)

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Props bernhard-reiter, swissspidy.

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[swissspidy]

Committed in https://core.trac.wordpress.org/changeset/57660

[ockham]

Thank you for landing this @swissspidy!