NOTE

Need to do some more research, this might be a problem with my addon, will update as I go...

There doesn't seem to be an adapter for control panels, so if you try to use blocks in a control panel, the block transforms will never run, meaning we lose out on functionality like create a resolveuid link for links.

Steps to reproduce

1. Create a control panel with blocks in it (e.g. enable https://github.com/pretagov/volto-slots-editor)
2. Create a text block with a link in it
3. Save the control panel
4. View the data stored from the control panel

Expected result

The URL of the link has been changed to resolveuid

Actual result

The URL stays as the absolute URL created from the POST request.

Investigation

• plone.restapi/src/plone/restapi/deserializer/controlpanels/__init__.py

  Lines 55 to 57 in 259d969

  	deserializer = queryMultiAdapter(
  	(field, fake_context, self.request), IFieldDeserializer
  	)

  should trigger the Blocks field deserialization handler
• It does correctly trigger it, but iter_block_transform_handlers doesn't return the handlers correctly in the subscribers request in

  plone.restapi/src/plone/restapi/blocks.py

  Lines 42 to 57 in 259d969

  	def iter_block_transform_handlers(context, block_value, interface):
  	"""Find valid handlers for a particular block transformation.
  	Looks for adapters of the context and request to this interface.
  	Then skips any that are disabled or don't match the block type,
  	and returns the remaining handlers sorted by `order`.
  	"""
  	block_type = block_value.get("@type", "")
  	handlers = []
  	for handler in subscribers((context, getRequest()), interface):
  	if handler.block_type == block_type or handler.block_type is None:
  	handler.blockid = id
  	handlers.append(handler)
  	for handler in sorted(handlers, key=lambda h: h.order):
  	if not getattr(handler, "disabled", False):
  	yield handler

• Looks like the FakeDXContext doesn't get the subscriptions correctly. If I put a debugger in the subscription code above and swap the context passed in (i.e. the FakeDXContext) for a real object (e.g. with plone.api.portal.get() or an unrestrictedTraverse to a page) the subscribers are correctly found and triggered