This was a tricky merge (wallet refactor). Please double check my
changes to CreateTransactionInternal(...) in src/wallet/spend.cpp, and to
SendGenerationTransaction(...) in src/wallet/rpc/elements.cpp.
Lastly, I got all the tests passing, but I'm not certain that the changes
with fixed_change_pos in CreateTransactionInternal were correct.
Since #25273, the behavior of 'inserting change at a random
position' is instructed by passing std::nullopt instead of -1.
Also, added missing documentation about the meaning of
'change_pos=std::nullopt' inside 'CWallet::CreateTransaction()'
Instead of having a separate CCoinControl::SelectExternal function, we
can use the normal CCoinControl::Select function and explicitly use
PreselectedInput::SetTxOut in the caller. The semantics of what an
external input is remains.
43de4d3630 doc: fix typos (Sjors Provoost)
Pull request description:
This PR fixes typos found by lint-spelling.py using codespell 2.2.6.
Our CI linter job uses codespell 2.2.5 and found fewer typos that I did locally. In any case it's happy now.
ACKs for top commit:
pablomartin4btc:
re ACK 43de4d3630
Tree-SHA512: c032fe86cb49c924a468385653b31f309a9db68c478d70335bba3e65a1ff3826abe80284fe00a090ab5a509e1edbf17e476f6922fb15d055e50f1103dad2ccb0
The current argument name and description are dangerous as it don't
describe the case where the user selects the recipient output as the
change address. This one could end up been increased by the inputs
minus outputs remainder. Which, when bumpfee adds new inputs
to the transaction, leads the process to send more coins to the
recipient. Which is not what the user would expect from a
'reduce_output' param naming.
Co-authored-by: Murch <murch@murch.one>
ad0c469d98 wallet: Use CTxDestination in CRecipient rather than scriptPubKey (Andrew Chow)
07d3bdf4eb Add PubKeyDestination for P2PK scripts (Andrew Chow)
1a98a51c66 Allow CNoDestination to represent a raw script (Andrew Chow)
8dd067088d Make WitnessUnknown members private (Andrew Chow)
Pull request description:
For silent payments, we want to provide a `SilentPaymentsDestination` to be used as the recipient, which requires `CRecipient` to use something other than just the `scriptPubKey` as we cannot know the output script for a silent payment prior to transaction creation. `CTxDestination` seems like the obvious place to add a `SilentPaymentsDestination` as it is our internal representation of an address.
In order to still allow paying to arbitrary scriptPubKeys (e.g. for data carrier outputs, or the user hand crafted a raw transaction that they have given to `fundrawtransaction`), `CNoDestination` is changed to contain raw scripts.
Additionally, P2PK scripts are now interpreted as a new `PubKeyDestination` rather than `PKHash`. This results in some things that would have given an address for P2PK scripts to no longer do so. This is arguably more correct.
`ExtractDestination`'s behavior is slightly changed for the above. It now returns `true` for those destinations that have addresses, so P2PK scripts now result in `false`. Even though it returns false for `CNoDestination`, the script will now be included in that `CNoDestination`.
Builds on #28244
ACKs for top commit:
josibake:
ACK https://github.com/bitcoin/bitcoin/pull/28246/commits/ad0c469d98c51931b98b7fd937c6ac3eeaed024e
Tree-SHA512: ef3f8f3c7284779d9806c77c85b21caf910a79a1f7e7f1b51abcc0d7e074f14e00abf30f625a13075e41d94dad6202c10ddff462c0ee74c2ca4aab585b145a52
When a transaction uses an unconfirmed input, preceding this commit it
would not consider the feerate of the parent transaction. Given a parent
transaction with a lower ancestor feerate, this resulted in the new
transaction's ancestor feerate undershooting the target feerate.
This commit changes how we calculate the effective value of unconfirmed UTXOs.
The effective value of unconfirmed UTXOs is decreased by the fee
necessary to bump its ancestry to the target feerate. This also impacts
the calculation of the waste metric: since the estimate for the current
fee is increased by the bump fees, unconfirmed UTXOs current fees appear less
favorable compared to their unchanged long term fees.
This has one caveat: if multiple UTXOs have overlapping ancestries, each
of their individual estimates will account for bumping all ancestors.
If the user used a custom change address, it may not be detected as a
change output, resulting in an additional change output being added to
the bumped transaction. We can avoid this issue by allowing the user to
specify the position of the change output.
Since the kernel library no longer depends on the system file, move it
to the common library instead in accordance to the diagram in
doc/design/libraries.md.
Simple example:
1) User_1 sends 0.1 btc to user_2 on a low fee transaction.
2) After few hours, the tx is still in the mempool, user_2
is not interested anymore, so user_1 decides to cancel
it by sending coins back to himself.
3) User_1 has the bright idea of opening the explorer and
copy the change output address of the transaction. Then
call bumpfee providing such output (in the "outputs" arg).
Currently, this is not possible. The wallet fails with
"Unable to create transaction. Transaction must have at least
one recipient" error.
The error reason is that we discard the provided output from
the recipients list and set it inside the coin control
so the process adds it later (when the change is calculated).
But.. there is no later if the tx has no outputs.
When doing the feerate check for bumped transactions that replace the
outputs, we need to consider that the size of the new outputs may be
different from the old outputs and calculate the minimum feerate accordingly.
1dc03dda05 [doc] remove non-signaling mentions of BIP125 (glozow)
32024d40f0 scripted-diff: remove mention of BIP125 from non-signaling var names (glozow)
Pull request description:
We have pretty thorough documentation of our RBF policy in doc/policy/mempool-replacements.md. It enumerates each rule with several sentences of rationale. Also, each rule pretty much has its own function (3 and 4 share one), with extensive comments. The doc states explicitly that our rules are similar but differ from BIP125, and contains a record of historical changes to RBF policy.
We should not use "BIP125" as synonymous with our RBF policy because:
- Our RBF policy is different from what is specified in BIP125, for example:
- the BIP does not mention our rule about the replacement feerate being higher (our Rule 6)
- the BIP uses minimum relay feerate for Rule 4, while we have used incremental relay feerate since #9380
- the "inherited signaling" question (CVE-2021-31876). Call it discrepancy, ambiguous wording, doc misinterpretation, or implementation details, I would recommend users refer to doc/policy/mempool-replacements.md
- the signaling policy is configurable, see #25353
- Our RBF policy may change further
- We have already marked BIP125 as only "partially implemented" in docs/bips.md since 1fd49eb498
- See comments from people who are not me recently:
- https://github.com/bitcoin/bitcoin/pull/25038#discussion_r909507429
- https://github.com/bitcoin/bitcoin/pull/25575#issuecomment-1179519204
This PR removes all non-signaling mentions of BIP125 (if people feel strongly, we can remove all mentions of BIP125 period). It may be useful to refer to the concept of "tx opts in to RBF if it has at least one nSequence less than (0xffffffff - 1)" as "BIP125 signaling" because:
- It is succint.
- It has already been widely marketed as BIP125 opt-in signaling.
- Our API uses it when referring to signaling (e.g. getmempoolentry["bip125-replaceable"] and wallet error message "not BIP 125 replaceable"). Changing those is more invasive.
- If/when we have other ways to signal in the future, we can disambiguate them this way. See #25038 which proposes another way of signaling, and where I pulled these commits from.
Alternatives:
- Changing our policy to match BIP125. This doesn't make sense as, for example, we would have to remove the requirement that a replacement tx has a higher feerate (Rule 6).
- Changing BIP125 to match what we have. This doesn't make sense as it would be a significant change to a BIP years after it was finalized and already used as a spec to implement RBF in other places.
- Document our policy as a new BIP and give it a number. This might make sense if we don't expect things to change a lot, and can be done as a next step.
ACKs for top commit:
darosior:
ACK 1dc03dda05
ariard:
ACK 1dc03dda
t-bast:
ACK 1dc03dda05
Tree-SHA512: a3adc2039ec5785892d230ec442e50f47f7062717392728152bbbe27ce1c564141f85253143f53cb44e1331cf47476d74f5d2f4b3cd873fc3433d7a0aa783e02
When bumping the fee of a transaction containing external inputs,
determine the weights of those inputs. Because signatures can have a
variable size, the script is executed with a special SignatureChecker
which will compute the total weight of the signatures in the transaction
and the weight if they were all maximum size signatures. This allows us
to compute the maximum weight of the input for use during coin
selection.
