[CHIA-3793] after the hard fork, disallow block references #20218
Conversation
arvidn
added
the
Changed
arvidn
force-pushed
the
hard-fork-generator-refs
branch
from
82dab9f to
e90d3c4
Compare
arvidn
force-pushed
the
hard-fork-generator-refs
branch
from
e90d3c4 to
f4a0b5e
Compare
|
| # 8c. The generator ref list must not point to a height >= this block's height | ||
| if block.transactions_generator_ref_list in (None, []): | ||
| if block.transactions_generator_ref_list == []: | ||
| if block.transactions_info.generator_refs_root != bytes([1] * 32): |
There was a problem hiding this comment.
This is such a bizarre magic number. I'm very puzzled why we wouldn't just use the serialization for the empty list. But I don't suppose it much matters now.
There was a problem hiding this comment.
this isn't a list, it's a bytes32. it must always be 32 bytes in the serialization. Still, It could be a named constant.
| # 8b. The generator ref list length must be less than or equal to MAX_GENERATOR_REF_LIST_SIZE entries | ||
| # 8c. The generator ref list must not point to a height >= this block's height | ||
| if block.transactions_generator_ref_list in (None, []): | ||
| if block.transactions_generator_ref_list == []: |
There was a problem hiding this comment.
Is this just a tidy-up, or is it required?
There was a problem hiding this comment.
correct, this is unrelated. I was a bit surprised mypy didn't flag this. transaction_generator_ref_list is not Optional[]. It can't be None.
|
|
||
| # With hard fork 2 we ban transactions_generator_ref_list. | ||
| if prev_tx_height >= self.constants.HARD_FORK2_HEIGHT and block.transactions_generator_ref_list != []: | ||
| return None, Err.TOO_MANY_GENERATOR_REFS |
There was a problem hiding this comment.
I'm a bit puzzled as to why this is checked in multiple places. Maybe one is for all blocks and another is just for "transaction blocks"?
There was a problem hiding this comment.
We check it in BlockTools, to make sure no test is trying to create an invalid block.
We check it in block body validation, which is the main block validation function.
We also check it when validating unfinished blocks, which is a bit trickier because the height of the block isn't as well known.
Purpose:
With hard fork 2, we want to disallow block references. We have not seen any benefit or use of them so far. We currently compress block generators using (internal) back references. Deduplicating structures.
Disallowing block generators has the following upsides:
There are two additional commits in this PR.