Inspired by https://github.com/bitcoin/bitcoin/pull/27446, this commit
implements the proposal detailed in the comment
https://github.com/bitcoin/bitcoin/pull/27446#issuecomment-1516600820.
Rationale.
Introduce the ability to configure a custom target time between blocks in a
custom Bitcoin signet network. This enhancement enables users to create a signet
that is more conducive to testing. The change enhances the flexibility of signet,
rendering it more versatile for various testing scenarios. For instance, I am
currently working on setting up a signet with a 30-second block time. However,
this caused numerous difficulty adjustments, resulting in an inconsistent
network state. Regtest isn't a viable alternative for me in this context since
we prefer defaults to utilize our custom signet when configured, without
impeding local regtest development.
Implementation.
If the challenge format is "OP_RETURN PUSHDATA<params> PUSHDATA<actual
challenge>", the actual challenge from the second data push is used as the
signet challenge, and the parameters from the first push are used to configure
the network. Otherwise the challenge is used as is.
Under the previous rules, such a signet challenge would always evaluate to
false, suggesting that it is likely not in use by anyone. Updating bitcoind to a
version that includes this change will not cause any disruptions - existing
signet challenges will retain their original meaning without alteration.
The only parameter currently available is "target_spacing" (default 600
seconds). To set it, place "0x01<target_spacing as uint64_t, little endian>" in
the params. Empty params are also valid. If other network parameters are added
in the future, they should use "0x02<option 2 value>", "0x03<option 3 value>",
etc., following the protobuf style.
Two public functions were added to chainparams.h:
- ParseWrappedSignetChallenge: Extracts signet params and signet challenge
from a wrapped signet challenge.
- ParseSignetParams: Parses <params> bytes of the first data push.
Function ReadSigNetArgs calls ParseWrappedSignetChallenge and ParseSignetParams
to implement the new meaning of signetchallenge.
The description of the flag -signetchallenge was updated to reflect the changes.
A new unit tests file, chainparams_tests.cpp, was added, containing tests for
ParseWrappedSignetChallenge and ParseSignetParams.
The test signet_parse_tests from the file validation_tests.cpp was modified to
ensure proper understanding of the new logic.
In the functional test feature_signet.py, a test case was added with the value
of -signetchallenge set to the wrapped challenge, setting spacing to 30 seconds
and having the actual challenge OP_TRUE.
The Signet miner was updated, introducing a new option --target-spacing with a
default of 600 seconds. It must be set to the value used by the network.
Example.
I tested this commit against Mutinynet, a signet running on a custom fork of
Bitcoin Core, implementing 30s target spacing. I successfully synchronized the
blockchain using the following config:
signet=1
[signet]
signetchallenge=6a4c09011e000000000000004c25512102f7561d208dd9ae99bf497273e16f389bdbd6c4742ddb8e6b216e64fa2928ad8f51ae
addnode=45.79.52.207:38333
dnsseed=0
The content of this wrapped challenge:
6a OP_RETURN
4c OP_PUSHDATA1
09 (length of signet params = 9)
011e00000000000000 (signet params: 0x01, pow_target_spacing=30)
4c OP_PUSHDATA1
25 (length of challenge = 37)
512102f7561d208dd9ae99bf497273e16f389bdbd6c4742ddb8e6b216e64fa2928ad8f51ae
(original Mutinynet challenge, can be found here:
https://blog.mutinywallet.com/mutinynet/ )
fb6d51eb25 signet/miner: Use argparse exclusive groups (Anthony Towns)
338a266a9a signet/miner: add support for a poolnum/poolid tag in mined blocks (Anthony Towns)
409ab7d35b signet/miner: add Generate.mine function (Anthony Towns)
7b31332370 signet/miner: add Generate.gbt function (Anthony Towns)
85c5c0bea9 signet/miner: add Generate.next_block_time function (Anthony Towns)
5540e6ca49 signet/miner: move next_block_* functions into new Generator class (Anthony Towns)
35f4631196 signet/miner: rename do_decode_psbt to decode_psbt (Anthony Towns)
aac040b439 signet/miner: drop create_coinbase function (Anthony Towns)
16951f549e signet/miner: drop do_createpsbt function (Anthony Towns)
3aed0a4284 signet/miner: drop get_reward_address function (Anthony Towns)
Pull request description:
Refactors the code a bunch, and adds `--poolnum` / `--poolid` options so that signers can tag their coinbases in a way that explorers can recognise (see also https://github.com/bitcoin-data/mining-pools/pull/82 and https://github.com/mempool/mempool/issues/2903).
The refactoring in particular helps enable the "try using inquisition's getblocktemplate, and if that doesn't work fall back to core's getblocktemplate" logic, as described/implemented in https://github.com/bitcoin-inquisition/bitcoin/pull/7
ACKs for top commit:
achow101:
ACK fb6d51eb25
danielabrozzoni:
Code review ACK fb6d51eb25
Tree-SHA512: d84095c4045ab196685b847e04ce2cdaedf387bc2527430ede918318dc5b70bf3d87b754264016f895f506fac70d4fdea5ef3cd8c3c375fd586afeae01e045e5
In order to ensure that the change of nVersion to a uint32_t in the
previous commit has no effect, rename nVersion to version in this commit
so that reviewers can easily spot if a spot was missed or if there is a
check somewhere whose semantics have changed.
Running the miner under python >= 3.12 causes a SyntaxWarning. The problem was
already present in previous versions, but it only triggered a
DeprecationWarning, which was not shown by default.
The change is useful for future-proofing the code base, since future python
versions will start to exit with a runtime exception (see the reference given
later).
Command to see the warning at runtime under python3.11 (DeprecationWarning,
needs "-Walways"):
$ python3.11 -Walways ./contrib/signet/miner
<BASE>/contrib/signet/miner:33: DeprecationWarning: invalid escape sequence '\d'
RE_MULTIMINER = re.compile("^(\d+)(-(\d+))?/(\d+)$")
2023-11-15 16:02:49 ERROR Must specify command
Command to see the warning at runtime under python3.12 (SyntaxWarning, no
modifiers needed):
$ python3.12 ./contrib/signet/miner
<BASE>/contrib/signet/miner:33: SyntaxWarning: invalid escape sequence '\d'
RE_MULTIMINER = re.compile("^(\d+)(-(\d+))?/(\d+)$")
2023-11-15 16:03:00 ERROR Must specify command
Reference ( https://docs.python.org/3.8/library/re.html ):
Regular expressions use the backslash character ('\') [...]. This collides
with Python’s usage of the same character for the same purpose in string
literals; [...]
Also, please note that any invalid escape sequences in Python’s usage of the
backslash in string literals now generate a DeprecationWarning and in the
future this will become a SyntaxError.
The solution is to use Python’s raw string notation for regular expression
patterns;
PSBT signing was changed to use SIGHASH_DEFAULT by default in #22514.
The signet miner script sets the sighash type of the created PSBT to
SIGHASH_ALL, hence this leads to a sighash mismatch when the
`walletprocesspsbt` RPC is called. Fix this by explicitly passing the
correct sighash type.
Note that the same change was needed in one of our functional tests,
see commit d3992669df.
Reported by gruve-p.
When mining the first block of a new signet chain, pick a timestamp for
the first block so that after mining 100 blocks the timestamp will be
back to the current time -- this prevents an unnecessary delay before
any miner rewards have matured enough to be spent. This takes into
account that the delta between blocks may be shorter than 10 minutes due
to attempting to increase the difficulty to match --nbits, but does not
take into account the time spent actually generating the 100 blocks.
