When lockinontimeout is true, we don't transition directly from STARTED
to LOCKED_IN, so don't imply that we do.
If startheight or timeoutheight are not on a retarget boundary, they
behave as if they had been rounded up to the next retarget boundary,
so to keep things simple, require them to be at a boundary.
If timeoutheight is less than two retarget periods later than startheight,
behaviour when lockinontimeout is true (one retarget period of STARTED,
one of MUST_SIGNAL, one of LOCKED_IN, then ACTIVE) will not match
behaviour when lockinontimeout is false (one retarget period of STARTED,
then either LOCKED_IN or FAILED), so disallow that as well.
This removes the FAILING state and adds compulsory signalling during a
new MUST_SIGNAL phase during the last retarget period prior to the
timeout height.
This ensures that if a deployment occurs using bip8 with
lockinontimeout=false and timeoutheight=N, that a later deployment using
bip8 with lockinontimeout=true and timeoutheight=K, where K<N that any
chain where LOCKED_IN is reached prior to height K, will be accepted as
valid by nodes using either set of deployment parameters.
It also ensures that the soft-fork's changed rules are only enforced
on chain a retarget period after signalling indicates enforcement is
expected (which was not previously the case if the FAILING to ACTIVE
transition took place).
6ef71b344c BIP155: Small text improvements (Hennadii Stepanov)
562f1d7188 BIP155: Mention SHA3-256 explicitly (Hennadii Stepanov)
Pull request description:
It seems better to clarify that `CHECKSUM` in Tor onion v3 address uses SHA3-256 hash function.
ACKs for top commit:
vasild:
ACK 6ef71b344
laanwj:
ACK 6ef71b344c
Tree-SHA512: b88c7dfeeda2a99cfe1042c9f4e7cbeb6047882bf97ce9c1dd5e1f4a30203a9a03702638cc4b6c3b573f6c0a05b73a5ca43a77352a5ca24a32d19be129f8b317
The Bitcoin Core source code has `VARINT` type which is different than
the "variable integer" format used all over the P2P protocol and also
for the "services" field in this BIP. The latter is called `CompactSize`
in some BIPs and also in the Bitcoin Core source code, thus use the word
`CompactSize` to refer to it and link to its documentation.
The current version of the spec requires creator role to initialize empty input fields, but says nothing about output field initialization. At the same time, the following role, updater, "should also add redeemScripts, witnessScripts, and BIP 32 derivation paths to the input and output data if it knows them.", which does not make any sense if the fields were uninitialized. The [current Bitcoin Core implementation does this](a24806c25d/src/psbt.cpp (L12)), and [other PSBT implementations, like rust-bitcoin, follow this practice](https://github.com/rust-bitcoin/rust-bitcoin/blob/master/src/util/psbt/mod.rs#L59)
