5fa4055452861ca1700008e1761815e88b29fae7 net: do not `break` when `addr` is not from a distinct network group (brunoerg)
Pull request description:
When the address is from a network group we already caught,
do a `continue` and try to find another address until conditions
are met or we reach the limit (`nTries`).
ACKs for top commit:
amitiuttarwar:
utACK 5fa4055452861ca1700008e1761815e88b29fae7
achow101:
ACK 5fa4055452861ca1700008e1761815e88b29fae7
mzumsande:
utACK 5fa4055452861ca1700008e1761815e88b29fae7
Tree-SHA512: 225bb6df450b46960db934983c583e862d1a17bacfc46d3657a0eb25a0204e106e8cd18de36764e210e0a92489ab4b5773437e4a641c9b455bde74ff8a041787
7c853619ee9ea17a79f1234b6c7871a45ceadcb9 refactor: Drop unsafe AsBytePtr function (Ryan Ofsky)
Pull request description:
Replace calls to `AsBytePtr` with calls to `AsBytes` or `reinterpret_cast`. `AsBytePtr` is just a wrapper around `reinterpret_cast`. It accepts any type of pointer as an argument and uses `reinterpret_cast` to cast the argument to a `std::byte` pointer.
Despite taking any type of pointer as an argument, it is not useful to call `AsBytePtr` on most types of pointers, because byte representations of most types will be platform specific or undefined. Also, because it is named similarly to the `AsBytes` function, `AsBytePtr` looks safer than it actually is. Both `AsBytes` and `AsBytePtr` call reinterpret_cast internally and may be unsafe to use with certain types, but AsBytes at least has some type checking and can only be called on `Span` objects, while `AsBytePtr` can be called on any pointer argument.
The change was motivated by discussion on #27973 and #27927 and is compatible with those PRs
ACKs for top commit:
jonatack:
re-ACK 7c853619ee9ea17a79f1234b6c7871a45ceadcb9
sipa:
utACK 7c853619ee9ea17a79f1234b6c7871a45ceadcb9
achow101:
ACK 7c853619ee9ea17a79f1234b6c7871a45ceadcb9
Tree-SHA512: 200d858b1d4d579f081a7f9a14d488a99713b4918b4564ac3dd5c18578d927dbd6426e62e02f49f04a3fa73ca02ff7109c495cb0b92bec43c27d9b74e2f95757
fae7c50d201726f605938c3511dd9119efeea5ec test: Run fuzz tests on macOS (MarcoFalke)
Pull request description:
Any reason not to?
ACKs for top commit:
jamesob:
Github ACK fae7c50d20
dergoegge:
utACK fae7c50d201726f605938c3511dd9119efeea5ec
Tree-SHA512: e45122d73fafb17cea312258314b826cb0745e08daadd28465f687ec02d4c127d2f8cbe20179a9fff5712038850c02c968abb4838fa088b7555e28709317d3a3
As far as I can tell, the code calling for these includes was removed in:
6e68ccbefea6509c61fc4405a391a517c6057bb0 #24356
82d360b5a88d9057b6c09b61cd69e426c7a2412d #21387
Replace calls to AsBytePtr with direct calls to AsBytes or reinterpret_cast.
AsBytePtr is just a wrapper around reinterpret_cast. It accepts any type of
pointer as an argument and uses reinterpret_cast to cast the argument to a
std::byte pointer.
Despite taking any type of pointer as an argument, it is not useful to call
AsBytePtr on most types of pointers, because byte representations of most types
will be implmentation-specific. Also, because it is named similarly to the
AsBytes function, AsBytePtr looks safer than it actually is. Both AsBytes and
AsBytePtr call reinterpret_cast internally and may be unsafe to use with
certain types, but AsBytes at least has some type checking and can only be
called on Span objects, while AsBytePtr can be called on any pointer argument.
Co-authored-by: Pieter Wuille <pieter@wuille.net>
fa38d862358b87219b12bf31236c52f28d9fc5d6 Use only Span{} constructor for byte-like types where possible (MarcoFalke)
fa257bc8312b91c2d281f48ca2500d9cba353cc5 util: Allow std::byte and char Span serialization (MarcoFalke)
Pull request description:
Seems odd to require developers to cast all byte-like spans passed to serialization to `unsigned char`-spans. Fix that by passing and accepting byte-like spans as-is. Finally, add tests and update the code to use just `Span` where possible.
ACKs for top commit:
sipa:
utACK fa38d862358b87219b12bf31236c52f28d9fc5d6
achow101:
ACK fa38d862358b87219b12bf31236c52f28d9fc5d6
ryanofsky:
Code review ACK fa38d862358b87219b12bf31236c52f28d9fc5d6. This looks great. The second commit really removes a lot of boilerplate and shows why the first commit is useful.
Tree-SHA512: 788592d9ff515c3ebe73d48f9ecbb8d239f5b985af86f09974e508cafb0ca6d73a959350295246b4dfb496149bc56330a0b5d659fc434ba6723dbaba0b7a49e5
79d343a642f985801da463b03a0627a59a095238 http: update libevent workaround to correct version (stickies-v)
Pull request description:
The libevent bug described in 5ff8eb2637 was already patched in [release-2.1.9-beta](https://github.com/libevent/libevent/releases/tag/release-2.1.9-beta), with cherry-picked commits [5b40744d1581447f5b4496ee8d4807383e468e7a](5b40744d15) and [b25813800f97179b2355a7b4b3557e6a7f568df2](b25813800f).
There should be no side-effects by re-applying the workaround on an already patched version of libevent (as is currently done in master for people running libevent between 2.1.9 and 2.1.12), but it is best to just set the correct version number to avoid confusion.
This will prevent situations like e.g. in https://github.com/bitcoin/bitcoin/pull/27909#discussion_r1238858604, where a reverse workaround was incorrectly applied to the wrong version range.
ACKs for top commit:
fanquake:
ACK 79d343a642f985801da463b03a0627a59a095238
Tree-SHA512: 56d2576411cf38e56d0976523fec951e032a48e35af293ed1ef3af820af940b26f779b9197baaed6d8b79bd1c7f7334646b9d73f80610d63cffbc955958ca8a0
3c83b1d884b419adece95b335b6e956e7459a7ef doc: Add release note for wallet loading changes (Andrew Chow)
2636844f5353797a0b8e40a879652a0d345172ad walletdb: Remove loading code where the database is iterated (Andrew Chow)
cd211b3b9965b5070d68adc1a03043d82d904d5b walletdb: refactor decryption key loading (Andrew Chow)
31c033e5ca3b65f4f5345d5aa17aafedd637ef4f walletdb: refactor defaultkey and wkey loading (Andrew Chow)
c978c6d39cdeb78fc4720767b943d03d6a9a36d8 walletdb: refactor active spkm loading (Andrew Chow)
6fabb7fc99e60584d5f3a2cb01d39f761769a25d walletdb: refactor tx loading (Andrew Chow)
abcc13dd24889bc1c6af7b10da1da96d86aeafed walletdb: refactor address book loading (Andrew Chow)
405b4d914712b5de3b230a0e2960e89f6a0a2b2a walletdb: Refactor descriptor wallet records loading (Andrew Chow)
30ab11c49793d5d55d66c4dedfa576ae8fd6129c walletdb: Refactor legacy wallet record loading into its own function (Andrew Chow)
9e077d9b422ac3c371fe0f63da40e5092171a25e salvage: Remove use of ReadKeyValue in salvage (Andrew Chow)
ad779e9ece9829677c1735d8865f14b23459da80 walletdb: Refactor hd chain loading to its own function (Andrew Chow)
72c2a54ebb99fa3d91d7d15bd8a38a8d16e0ea6c walletdb: Refactor encryption key loading to its own function (Andrew Chow)
3ccde4599b5150577400c4fa9029f4146617f751 walletdb: Refactor crypted key loading to its own function (Andrew Chow)
7be10adff36c0dc49ae56ac571bb033cba7a565b walletdb: Refactor key reading and loading to its own function (Andrew Chow)
52932c5adb29bb9ec5f0bcde9a31b74113a20651 walletdb: Refactor wallet flags loading (Andrew Chow)
01b35b55a119dc7ac915fc621ecebcd5c50ccb55 walletdb: Refactor minversion loading (Andrew Chow)
Pull request description:
Currently when we load a wallet, we just iterate through all of the records in the database and add them completely statelessly. However we have some records which do rely on other records being loaded before they are. To deal with this, we use `CWalletScanState` to hold things temporarily until all of the records have been read and then we load the stateful things.
However this can be slow, and with some future improvements, can cause some pretty drastic slowdowns to retain this pattern. So this PR changes the way we load records by choosing to load the records in a particular order. This lets us do things such as loading a descriptor record, then finding and loading that descriptor's cache and key records. In the future, this will also let us use `IsMine` when loading transactions as then `IsMine` will actually be working as we now always load keys and descriptors before transactions.
In order to get records of a specific type, this PR includes some refactors to how we do database cursors. Functionality is also added to retrieve a cursor that will give us records beginning with a specified prefix.
Lastly, one thing that iterating the entire database let us do was to find unknown records. However even if unknown records were found, we would not do anything with this information except output a number in a log line. With this PR, we would no longer be aware of any unknown records. This does not change functionality as we don't do anything with unknown records, and having unknown records is not an error. Now we would just not be aware that unknown records even exist.
ACKs for top commit:
MarcoFalke:
re-ACK 3c83b1d884b419adece95b335b6e956e7459a7ef 🍤
furszy:
reACK 3c83b1d8
ryanofsky:
Code review ACK 3c83b1d884b419adece95b335b6e956e7459a7ef. Just Marco's suggested error handling fixes since last review
Tree-SHA512: 15fa56332fb2ce4371db468a0c674ee7a3a8889c8cee9f428d06a7d1385d17a9bf54bcb0ba885c87736841fe6a5c934594bcf4476a473616510ee47862ef30b4
32e2ffc39374f61bb2435da507f285459985df9e Remove the syscall sandbox (fanquake)
Pull request description:
After initially being merged in #20487, it's no-longer clear that an internal syscall sandboxing mechanism is something that Bitcoin Core should have/maintain, especially when compared to better maintained/supported alterantives, i.e [firejail](https://github.com/netblue30/firejail).
There is more related discussion in #24771.
Note that given where it's used, the sandbox also gets dragged into the kernel.
If it's removed, this should not require any sort of deprecation, as this was only ever an opt-in, experimental feature.
Closes#24771.
ACKs for top commit:
davidgumberg:
crACK 32e2ffc393
achow101:
ACK 32e2ffc39374f61bb2435da507f285459985df9e
dergoegge:
ACK 32e2ffc39374f61bb2435da507f285459985df9e
Tree-SHA512: 8cf71c5623bb642cb515531d4a2545d806e503b9d57bfc15a996597632b06103d60d985fd7f843a3c1da6528bc38d0298d6b8bcf0be6f851795a8040d71faf16
Instead of iterating the database to load the wallet, we now load
particular kinds of records in an order that we want them to be loaded.
So it is no longer necessary to iterate the entire database to load the
wallet.
Instead of dealing with these records when iterating the entire
database, find and handle them explicitly.
Loading of OLD_KEY records is bumped up to a LOAD_FAIL error as we will
not be able to use these types of keys which can lead to users missing
funds.
Instead of loading active spkm records as we come across them when
iterating the database, load them explicitly.
Due to exception handling changes, deserialization errors are now
treated as critical.
Instead of loading address book records as we come across them when
iterating the database, load them explicitly
Due to exception handling changes, deserialization errors are now
treated as critical.
The error message for noncritical errors has also been updated to
reflect that there's more data that could be missing than just address
book entries and tx data.
Instead of loading descriptor wallet records as we come across them when
iterating the database, loading them explicitly.
Exception handling for these records changes to a per-record type basis,
rather than globally. This results in some records now failing with a
critical error rather than a non-critical one.
Instead of loading legacy wallet records as we come across them when
iterating the database, load them explicitly.
Exception handling for these records changes to a per-record type basis,
rather than globally. This results in some records now failing with a
critical error rather than a non-critical one.
5fc4939e17509534eb36727b27ac0afb941e44f7 Added static_assert to check that base_blob is using whole bytes. (Brotcrunsher)
Pull request description:
Prior to this commit it was possible to create base_blobs with any arbitrary amount of bits, like base_blob<9>. One could assume that this would be a valid way to create a bit field that guarantees to have at least 9 bits. However, in such a case, base_blob would not behave as expected because the WIDTH is rounded down to the closest whole byte (simple integer division by 8). This commit makes sure that this oddity is detected and blocked by the compiler.
ACKs for top commit:
MarcoFalke:
lgtm ACK 5fc4939e17509534eb36727b27ac0afb941e44f7
theStack:
ACK 5fc4939e17509534eb36727b27ac0afb941e44f7
stickies-v:
ACK 5fc4939e17509534eb36727b27ac0afb941e44f7
Tree-SHA512: 6a06760f09d4a9e6f0b9338d4dddd4091f2ac59a843a443d9302959936d72c55f7cccd55a51ec3a5a799921f68be1b87968ef3c9c11d3389cbd369b5045bb50a
3168b08043546cd248a81563e21ff096019f1521 Bench test for EllSwift ECDH (Pieter Wuille)
42d759f239d1842ec0c662f8fa9ac0a9ff18a2cb Bench tests for CKey->EllSwift (dhruv)
2e5a8a437cf9ac78548891e61797b394571e27ae Fuzz test for Ellswift ECDH (dhruv)
c3ac9f5cf413e263803aac668a90a4ddd7316924 Fuzz test for CKey->EllSwift->CPubKey creation/decoding (dhruv)
aae432a764e4ceb7eac305458e585726225c7189 Unit test for ellswift creation/decoding roundtrip (dhruv)
eff72a0dff8fa83af873ad9b15dbac50b8d4eca3 Add ElligatorSwift key creation and ECDH logic (Pieter Wuille)
42239f839081bba9a426ebb9f1b7a56e35a2d428 Enable ellswift module in libsecp256k1 (dhruv)
901336eee751de088465e313dd8b500dfaf462b2 Squashed 'src/secp256k1/' changes from 4258c54f4e..705ce7ed8c (Pieter Wuille)
Pull request description:
This replaces #23432 and part of #23561.
This PR introduces all of the ElligatorSwift-related changes (libsecp256k1 updates, generation, decoding, ECDH, tests, fuzzing, benchmarks) needed for BIP324.
ElligatorSwift is a special 64-byte encoding format for public keys introduced in libsecp256k1 in https://github.com/bitcoin-core/secp256k1/pull/1129. It has the property that *every* 64-byte array is a valid encoding for some public key, and every key has approximately $2^{256}$ encodings. Furthermore, it is possible to efficiently generate a uniformly random encoding for a given public key or private key. This is used for the key exchange phase in BIP324, to achieve a byte stream that is entirely pseudorandom, even before the shared encryption key is established.
ACKs for top commit:
instagibbs:
reACK 3168b08043
achow101:
ACK 3168b08043546cd248a81563e21ff096019f1521
theStack:
re-ACK 3168b08043546cd248a81563e21ff096019f1521
Tree-SHA512: 308ac3d33e9a2deecb65826cbf0390480a38de201918429c35c796f3421cdf94c5501d027a043ae8f012cfaa0584656da1de6393bfba3532ab4c20f9533f06a6
11d650060aed25273d860baa4e03168a778832bb feerate: For GetFeePerK() return nSatoshisPerK instead of round trip through GetFee (Andrew Chow)
Pull request description:
Returning the sats/kvb does not need to round trip through GetFee(1000) since the feerate is already stored as sats/kvb.
Fixes#27913, although this does bring up a larger question of how we should handle such large feerates in fuzzing.
ACKs for top commit:
furszy:
Code ACK 11d65006
Tree-SHA512: bec1a0d4b572a0c810cf7eb4e97d729d67e96835c2d576a909f755b053a9707c2f1b3df9adb8f08a9c4d310cdbb8b1e1b42b9c004bd1ade02a07d8ce9e902138
77d6d89d43cc5969c98d9b4b56a1e877b473e731 net: net_processing, add `ProcessCompactBlockTxns` (brunoerg)
Pull request description:
When processing `CMPCTBLOCK` message, at some moments we can need to process compact block txns / `BLOCKTXN`, since all messages are handled by `ProcessMessage`, so we call `ProcessMessage` all over again.
ab98673f05/src/net_processing.cpp (L4331-L4348)
This PR creates a function called `ProcessCompactBlockTxns` to process it to avoid calling `ProcessMessage` for it - this function is also called when processing `BLOCKTXN` msg.
ACKs for top commit:
instagibbs:
reACK 77d6d89d43cc5969c98d9b4b56a1e877b473e731
ajtowns:
utACK 77d6d89d43cc5969c98d9b4b56a1e877b473e731
achow101:
ACK 77d6d89d43cc5969c98d9b4b56a1e877b473e731
Tree-SHA512: 4b73c189487b999a04a8f15608a2ac1966d0f5c6db3ae0782641e68b9e95cb0807bd065d124c1f316b25b04d522a765addcd7d82c541702695113d4e54db4fda
30778124b82791abdc6e930373460ef1dd587cb2 net: Give seednodes time before falling back to fixed seeds (Martin Zumsande)
Pull request description:
`-seednode` is an alternative bootstrap mechanism - when choosing it, we make a `AddrFetch` connection to the specified peer, gather addresses from them, and then disconnect. Presumably, if users specify a seednode they prefer addresses from that node over fixed seeds.
However, when disabling dns seeds and specifiying `-seednode`, `CConnman::ProcessAddrFetch()` immediately removes the entry from `m_addr_fetches` (before the seednode could give us addresses) - and once `m_addr_fetches` is empty, `ThreadOpenConnections` will add fixed seeds, resulting in a "race" between the fixed seeds and seednodes filling up AddrMan.
This PR suggests to check for any provided `-seednode` arg instead of using the size of `m_addr_fetches`, thus delaying the querying of fixed seeds for 1 minute when specifying any seednode (as we already do for `addnode` peers).
That way, we actually give the seednodes a chance for to provide us with addresses before falling back to fixed seeds.
This can be tested with `bitcoind -debug=net -dnsseed=0 -seednode=(...)` on a node without `peers.dat` and observing the debug log.
ACKs for top commit:
ajtowns:
utACK 30778124b82791abdc6e930373460ef1dd587cb2
achow101:
ACK 30778124b82791abdc6e930373460ef1dd587cb2
dergoegge:
Code review ACK 30778124b82791abdc6e930373460ef1dd587cb2
sr-gi:
ACK [3077812](30778124b8) with a tiny nit, feel free to ignore it
Tree-SHA512: 96446eb34c0805f10ee158a00a3001a07029e795ac40ad5638228d426e30e9bb836c64ac05d145f2f9ab23ec5a528f3a416e3d52ecfdfb0b813bd4b1ebab3c01
1771daa815ec014276cfcb30c934b0eaff4d72bf [fuzz] Show that SRD budgets for non-dust change (Murch)
941b8c6539d72890fd4e36fc900be9c300e1d737 [bug] Increase SRD target by change_fee (Murch)
Pull request description:
I discovered via fuzzing of another coin selection approach that at extremely high feerates SRD may find input sets that lead to transactions without change outputs. This is an unintended outcome since SRD is meant to always produce a transaction with a change output—we use other algorithms to specifically search for changeless solutions.
The issue occurs when the flat allowance of 50,000 ṩ for change is insufficient to pay for the creation of a change output with a non-dust amount, at and above 1,613 ṩ/vB. Increasing the change budget by `change_fee` makes SRD behave as expected at any feerates.
Note: The intermittent failures of `test/functional/interface_usdt_mempool.py` are a known issue: https://github.com/bitcoin/bitcoin/issues/27380
ACKs for top commit:
achow101:
ACK 1771daa815ec014276cfcb30c934b0eaff4d72bf
S3RK:
ACK 1771daa815ec014276cfcb30c934b0eaff4d72bf
Tree-SHA512: 3f36a3e317ef0a711d0e409069c05032bff1d45403023f3728bf73dfd55ddd9e0dc2a9969d4d69fe0a426807ebb0bed1f54abfc05581409bfe42c327acf766d4
0e21b56a44d53cec9080edb04410a692717f1ddc assumeutxo: catch and log fs::remove error instead of two exist checks (Andrew Toth)
Pull request description:
Fixes a block of code which seems to be incorrectly performing two existence checks instead of catching and logging errors. `fs::remove` returns `false` only if the file being removed does not exist, so it is redundant with the `fs::exists` check. If an error does occur when trying to remove an existing file, `fs::remove` will throw. See https://en.cppreference.com/w/cpp/filesystem/remove.
Also see https://github.com/bitcoin/bitcoin/blob/master/src/init.cpp#L326-L332 for a similar pattern.
ACKs for top commit:
MarcoFalke:
lgtm ACK 0e21b56a44d53cec9080edb04410a692717f1ddc
jamesob:
ACK 0e21b56a44
achow101:
ACK 0e21b56a44d53cec9080edb04410a692717f1ddc
Tree-SHA512: 137d0be5266cfd947e5e50ec93b895ac659adadf9413bef3468744bfdacee8dbe7d9bdfaf91784c45708610325d2241a114f4be4e622a108a639b3672b618fd2
The libevent bug described in 5ff8eb2637
was already patched in release-2.1.9-beta, with cherry-picked
commits 5b40744d1581447f5b4496ee8d4807383e468e7a and
b25813800f97179b2355a7b4b3557e6a7f568df2.
There should be no side-effects by re-applying the workaround on
an already patched version of libevent, but it is best to set the
correct version number to avoid confusion.
1c7d08b9acd33aff343228ada7e058e606cb1062 validation: Stricter assumeutxo error handling in InvalidateCoinsDBOnDisk (Ryan Ofsky)
9047337d369d800e6eca4d3b686139073a8e8905 validation: Stricter assumeutxo error handling in LoadChainstate (Ryan Ofsky)
Pull request description:
There are two places in assumeutxo code where it is calling `AbortNode` to trigger asynchronous shutdowns without returning errors to calling functions.
One case, in `LoadChainstate`, happens when snapshot validation succeeds, and there is an error trying to replace the background chainstate with the snapshot chainstate.
The other case, in `InvalidateCoinsDBOnDisk`, happens when snapshot validatiion fails, and there is an error trying to remove the snapshot chainstate.
In both cases the node is being forced to shut down, so it makes sense for these functions to raise errors so callers can know that an error happened without having to infer it from the shutdown state.
Noticed these cases while reviewing #27861, which replaces the `AbortNode` function with a `FatalError` function.
ACKs for top commit:
achow101:
ACK 1c7d08b9acd33aff343228ada7e058e606cb1062
TheCharlatan:
ACK 1c7d08b9acd33aff343228ada7e058e606cb1062
jamesob:
ACK 1c7d08b9acd33aff343228ada7e058e606cb1062 ([`jamesob/ackr/27862.1.ryanofsky.validation_stricter_assu`](https://github.com/jamesob/bitcoin/tree/ackr/27862.1.ryanofsky.validation_stricter_assu))
Tree-SHA512: fb1dcde3fa0e77b4ba0c48507d289552b939c2866781579c8e994edc209abc3cd29cf81c89380057199323a8eec484956abb1fd3a43c957ecd0e7f7bbfd63fd8
Also, fix a few bugs:
* Error: RPC command "enumeratesigners" not found in RPC_COMMANDS_SAFE_FOR_FUZZING or RPC_COMMANDS_NOT_SAFE_FOR_FUZZING. Please update test/fuzz/rpc.cpp.
* in run_once: ...format(" ".join(result.args), ... TypeError: sequence item 2: expected str instance, PosixPath found
28fff06afe98177c14a932abf95b380bb51c6653 test: Make linter to look for `BOOST_ASSERT` macros (Hennadii Stepanov)
47fe551e52d8b3f607d55ad20073c0436590e081 test: Kill `BOOST_ASSERT` (Hennadii Stepanov)
Pull request description:
One of the goals of https://github.com/bitcoin/bitcoin/pull/27783 was to get rid of the `BOOST_ASSERT` macros instead of including the `boost/assert.hpp` headers. See https://github.com/bitcoin/bitcoin/pull/27783#discussion_r1210612717.
It turns out that a couple of those macros sneaked into the codebase in https://github.com/bitcoin/bitcoin/pull/27790.
This PR makes the linter guard against new instances of the `BOOST_ASSERT` macros and replaces the current ones.
ACKs for top commit:
kevkevinpal:
ACK [28fff06](28fff06afe)
stickies-v:
ACK 28fff06af
TheCharlatan:
ACK 28fff06afe98177c14a932abf95b380bb51c6653
Tree-SHA512: 371f613592cf677afe0196d18c83943c6c8f1e998f57b4ff3ee58bfeff8636e4dac1357840d8611b4f7b197def94df10fe1a8ca3282b00b7b4eff4624552dda8
Prior to this commit it was possible to create base_blobs with any arbitrary amount of bits, like base_blob<9>. One could assume that this would be a valid way to create a bit field that guarantees to have at least 9 bits. However, in such a case, base_blob would not behave as expected because the WIDTH is rounded down to the closest whole byte (simple integer division by 8). This commit makes sure that this oddity is detected and blocked by the compiler.
I discovered via fuzzing of another coin selection approach that at
extremely high feerates SRD may find input sets that lead to
transactions without change outputs. This is an unintended outcome since
SRD is meant to always produce a transaction with a change output—we use
other algorithms to specifically search for changeless solutions.
The issue occures when the flat allowance of 50,000 ṩ for change is
insufficient to pay for the creation of a change output with a non-dust
amount, at and above 1,613 ṩ/vB. Increasing the change budget by
change_fees makes SRD behave as expected at any feerates.
