REST Block Renderer: Attributes registered using blocks.registerBlockType filter fails.

[phpbits]

Same issue with this one : #13249 but not only fo className. All attributes registered using blocks.registerBlockType returns invalid on REST block renderer.

{"code":"rest_invalid_param","message":"Invalid parameter(s): attributes","data":{"status":400,"params":{"attributes":"className is not a valid property of Object."}}}

[phpbits]

#15450

[talldan]

I don't think this is a bug, I expect the reason for this is that the attributes added via registerBlockType haven't been registered on the server, so ServerSideRender has no knowledge of them.

Registering the attributes server side as well (I think the block_type_metadata filter might be a candidate) should resolve the issue.

It's quite an old issue so I'll close it, if there's any further feedback though I can always reopen.