We should not proceed syncing headers from peers when the local system clock is incorrectly set.
A node with a system clock set too far back will typically fail early during startup when the chainstate detects the tip to be too far in the future. This means that in practice we don't expect the failure to ever happen in net_processing.cpp.
An exception is thrown from HeadersSyncState() in order to only compute the error condition once. An alternative would be to compute it a second time in TryLowWorkHeadersSync() to guard against calling HeadersSyncState(), and have an assert inside HeadersSyncState(). We shut down the process so possible resource leaks due to the exception should not be an issue, although none have been spotted. Throwing an exception also keeps the unit test straightforward.
Co-authored-by: Lőrinc <pap.lorinc@gmail.com>
The node currently continues low-work headers presync and requests more headers when its clock is more than `MAX_FUTURE_BLOCK_TIME` behind the chain-start MTP.
Record this behavior before the follow-up rejects the invalid elapsed-time calculation.
The unit test covers HeadersSyncState() behavior while the functional test covers net_processing.cpp behavior.
Co-authored-by: Lőrinc <pap.lorinc@gmail.com>
Some Python functional tests still use plain `assert x == y`.
The earlier commits convert the ambiguous assert patterns by hand, so this commit can rewrite the remaining safe cases mechanically.
The verify script excludes `wallet_bumpfee.py`, `test_framework/netutil.py`, and `test_framework/authproxy.py`, which still contain assert forms that the plain line-based substitution would misidentify.
-BEGIN VERIFY SCRIPT-
perl -pi -e 's/^(\s*)assert (.+?) == ([^,#]+?)$/\1assert_equal(\2, \3)/' $(git ls-files -- 'test/functional' \
':(exclude)test/functional/wallet_bumpfee.py' ':(exclude)test/functional/test_framework/netutil.py' ':(exclude)test/functional/test_framework/authproxy.py')
-END VERIFY SCRIPT-
Note that we unfortunately can't use a scripted diff here, as the
`sha256` symbol is also used for other instances (e.g. as function
in hashlib, or in the `UTXO` class in p2p_segwit.py).
