Implement Templatehash #4
Open
instagibbs wants to merge 6 commits into
Open
Conversation
darosior
reviewed
Jun 17, 2026
darosior
left a comment
darosior
left a comment
There was a problem hiding this comment.
Nice, thanks for going over all the annoying small conflicts (it's not .rehash() anymore, it's .txid_int, hah!). Just a few comments. Also CI linter is whining.
Comment on lines
+115
to
+118
| static CScript ScriptFromHex(const std::string& str) | ||
| { | ||
| return ToScript(*Assert(TryParseHex(str))); | ||
| } |
There was a problem hiding this comment.
Maybe use the modern way instead of reintroducing the helper dropped in 8756ccd?
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index d1c7419a73b..45b6cfa879b 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -112,11 +112,6 @@ static CScript ToScript(const T& byte_container)
return {span.begin(), span.end()};
}
-static CScript ScriptFromHex(const std::string& str)
-{
- return ToScript(*Assert(TryParseHex(str)));
-}
-
static std::string FormatScriptError(ScriptError_t err)
{
for (const auto& se : script_errors)
@@ -1827,7 +1822,7 @@ BOOST_AUTO_TEST_CASE(templatehash)
CTxIn{*Txid::FromHex("0437cd7f8525ceed2324359c2d0ba26006d92d856a9c20fa0241106ee5a597c9"), 21},
CTxIn{*Txid::FromHex("f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16"), 12}
};
- tx.vout.emplace_back(424242, ScriptFromHex("001482074bdf6ce32b071dd120a17cf99cbc01ad3080"));
+ tx.vout.emplace_back(424242, ToScript("001482074bdf6ce32b071dd120a17cf99cbc01ad3080"_hex));
// Construct the script to be spent, checking the (valid) hash of this transaction.
const uint256 vanilla_hash{GetTemplateHash(tx, 0)};
@@ -1838,7 +1833,7 @@ BOOST_AUTO_TEST_CASE(templatehash)
const CScript spent_spk{GetScriptForDestination(builder.GetOutput())};
// Outputs spent by the transaction whose template hash is to be checked.
- CTxOut dummy_txo{1'085'986, ScriptFromHex("76a914079ded3e3befdab0757fe0e8842aeffc0ff2160288ac")};
+ CTxOut dummy_txo{1'085'986, ToScript("76a914079ded3e3befdab0757fe0e8842aeffc0ff2160288ac"_hex)};
std::vector<CTxOut> spent_outputs{{CTxOut{424243, spent_spk}, dummy_txo}};
// Construct the witness data for the transaction.
@@ -1886,7 +1881,7 @@ BOOST_AUTO_TEST_CASE(templatehash)
// Output script:
{
CMutableTransaction tx2{tx};
- tx2.vout[0].scriptPubKey = ScriptFromHex("001482074bdf6ce32b071dd120a17cf99cbc01ad3081");
+ tx2.vout[0].scriptPubKey = ToScript("001482074bdf6ce32b071dd120a17cf99cbc01ad3081"_hex);
CheckTemplateMatch(tx2, Clone(spent_outputs), 0, /*is_valid=*/false, test_cases, std::string{"Template hash mismatches: incorrect output script."});
}
// This input's sequence:
@@ -1949,7 +1944,7 @@ BOOST_AUTO_TEST_CASE(templatehash)
// Other spent output's scriptpubkey:
{
std::vector<CTxOut> spent_outputs2(spent_outputs);
- spent_outputs2[1].scriptPubKey = ScriptFromHex("0014266a4832c001885db26e853ef1d1dde840f7dbaf");
+ spent_outputs2[1].scriptPubKey = ToScript("0014266a4832c001885db26e853ef1d1dde840f7dbaf"_hex);
CheckTemplateMatch(tx, std::move(spent_outputs2), 0, /*is_valid=*/true, test_cases, std::string{"Template hash matches with malleated scriptpubkey for other spent output."});
}| { | ||
| auto span{MakeUCharSpan(byte_container)}; | ||
| return {span.begin(), span.end()}; | ||
| } |
There was a problem hiding this comment.
This is re-defining the ToScript helper defined down below, maybe move the existing one up instead?
| // Making unknown public key versions (in BIP 342 scripts) non-standard | ||
| SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE, | ||
|
|
||
| // OP_TEMPLATEHASH validation (BIP xx) |
| flags |= SCRIPT_VERIFY_NULLDUMMY; | ||
| } | ||
|
|
||
| // Enforce OP_TEMPLATEHASH (BIPxx) |
Comment on lines
+110
to
+111
| SCRIPT_VERIFY_TAPROOT | | ||
| SCRIPT_VERIFY_TEMPLATEHASH}; |
There was a problem hiding this comment.
Nice. Much cleaner to be able to add it to mandatory flags from the get go.
Prior to activation, we always run into the discouragement and therefore never incorrectly return a consensus error for it. Post activation, we correctly return a consensus error. (And the stakes for getting this wrong are much lower now anyways.)
| bool is_valid, std::vector<TemplateHashTestCase>& cases, std::string comment) | ||
| { | ||
| Assert(tx.vin.size() == spent_outputs.size() && in_index < tx.vin.size()); | ||
| constexpr script_verify_flags FLAGS{MANDATORY_SCRIPT_VERIFY_FLAGS | SCRIPT_VERIFY_TEMPLATEHASH}; |
There was a problem hiding this comment.
SCRIPT_VERIFY_TEMPLATEHASH is now part of MANDATORY_SCRIPT_VERIFY_FLAGS. I guess you can just get rid of the FLAGS constant entirely now.
Owner
Author
There was a problem hiding this comment.
done, asserted it's in the set for locality of reasoning
instagibbs
force-pushed
the
2026-05-op_templatehash
branch
from
b7bef84 to
3c22f0b
Compare
Owner
Author
|
fixed CI complaints, addressed all points, fixed some of the git commit messages One note: |
instagibbs
force-pushed
the
2026-05-op_templatehash
branch
from
3c22f0b to
0aeb7df
Compare
Owner
Author
|
dropping |
The deployment is never active on mainnet or testnet. Activation parameters are intentionally left to be defined eventually and out of scope for this patchset. The deployment is always active on regtest, allowing us to extensively test expected behaviour of the proposed operation using the functional test suite. Co-Authored-By: Greg Sanders <gsanders87@gmail.com>
Script validation of OP_TEMPLATEHASH is enabled past its activation height, which means it is currently never enabled on mainnet/testnet and always is on regtest. Tapscript spends making use of OP_TEMPLATEHASH do not get relayed nor included in blocks until the soft fork is active. We no longer disconnect or ban for loose mempool transaction failures, so we can add the new flag directly to mandatory flag set, which makes disconnect and bans possible in blocks only post-activation. Co-Authored-by: Greg Sanders <gsanders87@gmail.com>
instagibbs
force-pushed
the
2026-05-op_templatehash
branch
from
0aeb7df to
53ff7dc
Compare
This introduces a new Script operation exclusively available in Tapscript context: OP_TEMPLATEHASH. This operation pushes the hash of the spending transaction on the stack. See BIP446 for details. This operation is introduced as replacing OP_SUCCESS206 (0xce). Co-Authored-By: Greg Sanders <gsanders87@gmail.com>
instagibbs
force-pushed
the
2026-05-op_templatehash
branch
from
53ff7dc to
762eb05
Compare
Sanity check the template hash by using it to commit to the transaction that must spend an output. Malleating committed fields must lead to a consensus failure, and changing non-committed fields is fine. We also add the option to generate test vectors from this unit test.
We introduce one specialized target focused on exercising the new `GetTemplateHash()` logic introduced for OP_TEMPLATEHASH, and one broader fuzz target which exercises using OP_TEMPLATEHASH on a variety of transactions while asserting invariants.
This leverages the extensive feature_taproot.py test framework to generate coverage for the numerous scenarii and mutations exercised there. Additionally, a separate feature_templatehash.py functional test is introduced for end-to-end testing of the commit-to-next-transaction use case, which does not fit nicely into the feature_taproot.py framework (assumes input independence).
instagibbs
force-pushed
the
2026-05-op_templatehash
branch
from
762eb05 to
8bea35b
Compare
Owner
Author
|
Fixed an error in the taproot test, removed a fuzz TODO, and added a couple unit test gaps. |
|
CI failure seems unrelated (" |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
No description provided.