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author | Antoine Poinsot <darosior@protonmail.com> | 2022-08-19 18:33:54 +0200 |
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committer | Antoine Poinsot <darosior@protonmail.com> | 2023-08-25 12:40:11 +0200 |
commit | fa7c46b503f0b69630f55dc43021d2099e3515ba (patch) | |
tree | ac592c760fe8d2d4f0391f29a6d419d3d8c6f453 /src/test/fuzz | |
parent | bdba7667d2d65f31484760a8e8420c488fc5f801 (diff) | |
download | bitcoin-fa7c46b503f0b69630f55dc43021d2099e3515ba.tar.xz |
descriptor: introduce a method to get the satisfaction size
In the wallet code, we are currently estimating the size of a signed
input by doing a dry run of the signing logic. This is unnecessary as
all outputs we are able to sign for can be represented by a descriptor,
and we can derive the size of a satisfaction ("signature") from the
descriptor itself directly.
In addition, this approach does not scale: getting the size of a
satisfaction through a dry run of the signing logic is only possible for
the most basic scripts.
This commit introduces the computation of the size of satisfaction per
descriptor. It's a bit intricate for 2 main reasons:
- We want to conserve the behaviour of the current dry-run logic used by
the wallet that sometimes assumes ECDSA signatures will be low-r,
sometimes not (when we don't create them).
- We need to account for the witness discount. A single descriptor may
sometimes benefit of it, sometimes not (for instance `pk()` if used as
top-level versus if used inside `wsh()`).
Diffstat (limited to 'src/test/fuzz')
-rw-r--r-- | src/test/fuzz/descriptor_parse.cpp | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/src/test/fuzz/descriptor_parse.cpp b/src/test/fuzz/descriptor_parse.cpp index 8ed659323c..a866cdca9a 100644 --- a/src/test/fuzz/descriptor_parse.cpp +++ b/src/test/fuzz/descriptor_parse.cpp @@ -112,7 +112,7 @@ static void TestDescriptor(const Descriptor& desc, FlatSigningProvider& sig_prov { // Trivial helpers. (void)desc.IsRange(); - (void)desc.IsSolvable(); + const bool is_solvable{desc.IsSolvable()}; (void)desc.IsSingleType(); (void)desc.GetOutputType(); @@ -131,7 +131,18 @@ static void TestDescriptor(const Descriptor& desc, FlatSigningProvider& sig_prov // If we could serialize to script we must be able to infer using the same provider. if (!out_scripts.empty()) { assert(InferDescriptor(out_scripts.back(), sig_provider)); + + // The ScriptSize() must match the size of the serialized Script. (ScriptSize() is set for all descs but 'combo()'.) + const bool is_combo{!desc.IsSingleType()}; + assert(is_combo || desc.ScriptSize() == out_scripts.back().size()); } + + const auto max_sat_maxsig{desc.MaxSatisfactionWeight(true)}; + const auto max_sat_nonmaxsig{desc.MaxSatisfactionWeight(true)}; + // We must be able to estimate the max satisfaction size for any solvable descriptor (but combo). + const bool is_nontop_or_nonsolvable{!is_solvable || !desc.GetOutputType()}; + const bool is_input_size_info_set{max_sat_maxsig && max_sat_nonmaxsig}; + assert(is_input_size_info_set || is_nontop_or_nonsolvable); } void initialize_descriptor_parse() |