A0-3032: Handle own blocks in sync

[timorleph]

Description

Blocks created by us should go through sync and get broadcast as soon as we create them.

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

(I might need to add tests, but I wanted to have this mostly done before my days off.)

• I have made corresponding changes to the existing documentation
• I have created new documentation

[woocash2]

I approve not to block, but I would need more context to understand better how Aura interacts with this code. I'd be grateful for a short explanation or some reference.

I understand that we have a wrapper for block_import which is adjusted for Aura. I get that check_block is aligned with inner.check_block, but import_block doesn't check_block which I perceive as some simplification which Aura won't break.

Tho I don't get why it doesn't break with Aura, and why we need this wrapper in the first place. Was there an issue that Aura sometimes didn't work with the original block_import?

[timorleph]

The issue this is dealing with is passing the blocks Aura produces through sync, so that they can be broadcast. The wrapper intercepts created blocks and first passes them through our sync, which only afterwards forwards them to the proper import queue.

Aura only makes very limited use of the results returned by the import queue we give it (as I outlined in one of the responses above), so intercepting the newly created blocks this way cannot impact its logic. I haven't checked whether check_block is used anywhere, but it does not modify the wrapped object and the current implementation returns the exact same thing as it did previously, so it should still work. The implementations of import_block do not usually call check_block in the first place, so that shouldn't be too weird – anyway, we let Aura perform all the necessary checks later, when it passes through the other import queue after going through our sync.