def chain(base_chain):
chain = api.build(
base_chain,
api.mine_blocks(3),
)
assert chain.get_canonical_head().block_number == 3
return chain
def test_import_block_with_reorg(chain, funded_address_private_key):
# mine ahead 3 blocks on the fork chain
fork_chain = api.build(
chain,
api.copy(),
api.mine_block(extra_data=b'fork-it'),
api.mine_blocks(2),
)
# mine ahead 2 blocks on the main chain
main_chain = api.build(
chain,
api.mine_blocks(2)
)
block_4 = main_chain.get_canonical_block_by_number(4)
f_block_4 = fork_chain.get_canonical_block_by_number(4)
assert f_block_4.number == block_4.number == 4
assert f_block_4 != block_4
assert f_block_4.header.difficulty <= block_4.header.difficulty
block_5 = main_chain.get_canonical_block_by_number(5)
f_block_5 = fork_chain.get_canonical_block_by_number(5)
assert f_block_5.number == block_5.number == 5
assert f_block_5 != block_5
assert f_block_5.header.difficulty <= block_5.header.difficulty
f_block_6 = fork_chain.get_canonical_block_by_number(6)
pre_reorg_chain_head = main_chain.header
# now we proceed to import the blocks from the fork chain into the main
# chain. Blocks 4 and 5 should import resulting in no re-organization.
for block in (f_block_4, f_block_5):
block_import_result = main_chain.import_block(block)
assert not block_import_result.new_canonical_blocks
assert not block_import_result.old_canonical_blocks
# ensure that the main chain head has not changed.
assert main_chain.header == pre_reorg_chain_head
# now we import block 6 from the fork chain. This should cause a re-org.
block_import_result = main_chain.import_block(f_block_6)
assert block_import_result.new_canonical_blocks == (f_block_4, f_block_5, f_block_6)
assert block_import_result.old_canonical_blocks == (block_4, block_5)
assert main_chain.get_canonical_head() == f_block_6.header
def test_block_gap_tracking(chain, funded_address, funded_address_private_key,
has_uncle, has_transaction, can_fetch_block):
# Mine three common blocks
common_chain = api.build(
chain,
api.mine_blocks(3),
)
assert common_chain.get_canonical_head().block_number == 3
assert common_chain.chaindb.get_chain_gaps() == ((), 4)
tx = new_transaction(
common_chain.get_vm(),
from_=funded_address,
to=ZERO_ADDRESS,
private_key=funded_address_private_key,
)
uncle = api.build(common_chain,
api.mine_block()).get_canonical_block_header_by_number(4)
uncles = [uncle] if has_uncle else []
transactions = [tx] if has_transaction else []
# Split and have the main chain mine four blocks, the uncle chain two blocks
main_chain, uncle_chain = api.build(
common_chain,
api.chain_split(
(
# We have four different scenarios for our replaced blocks:
# 1. Replaced by a trivial block without uncles or transactions
# 2. Replaced by a block with transactions
# 3. Replaced by a block with uncles
# 4. 2 and 3 combined
api.mine_block(uncles=uncles, transactions=transactions),
api.mine_block(),
api.mine_block(),
api.mine_block(),
),
# This will be the uncle chain
(
api.mine_block(extra_data=b'fork-it'),
api.mine_block(),
),
),
)
main_head = main_chain.get_canonical_head()
assert main_head.block_number == 7
assert uncle_chain.get_canonical_head().block_number == 5
assert main_chain.chaindb.get_chain_gaps() == ((), 8)
assert uncle_chain.chaindb.get_chain_gaps() == ((), 6)
main_header_6 = main_chain.chaindb.get_canonical_block_header_by_number(6)
main_header_6_score = main_chain.chaindb.get_score(main_header_6.hash)
gap_chain = api.copy(common_chain)
assert gap_chain.get_canonical_head() == common_chain.get_canonical_head()
gap_chain.chaindb.persist_checkpoint_header(main_header_6,
main_header_6_score)
# We created a gap in the chain of headers
assert gap_chain.chaindb.get_header_chain_gaps() == (((4, 5), ), 7)
# ...but not in the chain of blocks (yet!)
assert gap_chain.chaindb.get_chain_gaps() == ((), 4)
block_7 = main_chain.get_canonical_block_by_number(7)
block_7_receipts = block_7.get_receipts(main_chain.chaindb)
# Persist block 7 on top of the checkpoint
gap_chain.chaindb.persist_unexecuted_block(block_7, block_7_receipts)
assert gap_chain.chaindb.get_header_chain_gaps() == (((4, 5), ), 8)
# Now we have a gap in the chain of blocks, too
assert gap_chain.chaindb.get_chain_gaps() == (((4, 6), ), 8)
# Overwriting header 3 doesn't cause us to re-open a block gap
gap_chain.chaindb.persist_header_chain(
[main_chain.chaindb.get_canonical_block_header_by_number(3)])
assert gap_chain.chaindb.get_chain_gaps() == (((4, 6), ), 8)
# Now get the uncle block
uncle_block = uncle_chain.get_canonical_block_by_number(4)
uncle_block_receipts = uncle_block.get_receipts(uncle_chain.chaindb)
# Put the uncle block in the gap
gap_chain.chaindb.persist_unexecuted_block(uncle_block,
uncle_block_receipts)
assert gap_chain.chaindb.get_header_chain_gaps() == (((5, 5), ), 8)
assert gap_chain.chaindb.get_chain_gaps() == (((5, 6), ), 8)
# Trying to save another uncle errors as its header isn't the parent of the checkpoint
second_uncle = uncle_chain.get_canonical_block_by_number(5)
second_uncle_receipts = second_uncle.get_receipts(uncle_chain.chaindb)
with pytest.raises(CheckpointsMustBeCanonical):
gap_chain.chaindb.persist_unexecuted_block(second_uncle,
second_uncle_receipts)
# Now close the gap in the header chain with the actual correct headers
actual_headers = [
main_chain.chaindb.get_canonical_block_header_by_number(block_number)
for block_number in range(4, 7)
]
gap_chain.chaindb.persist_header_chain(actual_headers)
# No more gaps in the header chain
assert gap_chain.chaindb.get_header_chain_gaps() == ((), 8)
# We detected the de-canonicalized uncle and re-opened the block gap
assert gap_chain.chaindb.get_chain_gaps() == (((4, 6), ), 8)
if can_fetch_block:
# We can fetch the block even if the gap tracking reports it as missing if the block is
# a "trivial" block, meaning one that doesn't have transactions nor uncles and hence
# can be loaded by just the header alone.
block_4 = gap_chain.get_canonical_block_by_number(4)
assert block_4 == main_chain.get_canonical_block_by_number(4)
else:
# The uncle block was implicitly de-canonicalized with its header,
# hence we can not fetch it any longer.
with pytest.raises(BlockNotFound):
gap_chain.get_canonical_block_by_number(4)
# Add the missing block and assert the gap shrinks
assert gap_chain.chaindb.get_chain_gaps() == (((4, 6), ), 8)
block_4 = main_chain.get_canonical_block_by_number(4)
block_4_receipts = block_4.get_receipts(main_chain.chaindb)
gap_chain.chaindb.persist_unexecuted_block(block_4, block_4_receipts)
assert gap_chain.chaindb.get_chain_gaps() == (((5, 6), ), 8)