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Merge bitcoin/bitcoin#36261: test: cover PSBT unknown field merging
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91/100 · Strong
What the developer wrote
Authored by merge-script
Merge bitcoin/bitcoin#36261: test: cover PSBT unknown field merging
21e4ea8134d8ca95416e065490d99f82be66bd67 test: cover PSBT unknown field merging (w0xlt)
Pull request description:
Continuing the work from #35310 gere in agreement with w0xlt
This PR adds functional coverage for combinepsbt preserving unknown PSBT fields across global, input, and output maps, as suggested [here](https://github.com/bitcoin/bitcoin/pull/34893#issuecomment-4390043746).
The test covers both PSBTv0 and PSBTv2 by creating valid base PSBTs with `createpsbt`, injecting unknown key-value pairs into two copies, combining them, and asserting that all unknown fields are retained in the decoded result.
ACKs for top commit:
polespinasa:
ACK 21e4ea8134d8ca95416e065490d99f82be66bd67
nebula-21:
ACK 21e4ea8134d8ca95416e065490d99f82be66bd67
winterrdog:
tACK 21e4ea8134d8ca95416e065490d99f82be66bd67
w0xlt:
ACK 21e4ea8134d8ca95416e065490d99f82be66bd67
Tree-SHA512: 0f83ff2b9a519b613c6efaca3707bd8c6fdd00887370e16e927b19f059b751813737adc85ad81366f5c57b91226f56b3b0bdc996451f4d6bc9ec83aa4a189923
✓ Specific, descriptive subject✓ Names a concrete action or component✓ Provides detailed explanatory context✓ Mentions testing or verification✓ Links an issue, advisory, or supporting reference
What changed, and why it matters
This commit only adds a new automated test to Bitcoin Core. It checks that when two partially-signed Bitcoin transactions (PSBTs) are combined, any custom 'unknown' data fields attached to them are preserved correctly. There is no change to the actual Bitcoin Core software behavior—only test code was added.
Recommended action
No security action needed. This is a test-only change. Reviewers may optionally run the new functional test to confirm coverage.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The commit merges PR #36261, which adds functional test coverage in test/functional/rpc_psbt.py for combinepsbt’s handling of unknown PSBT key-value pairs. The test constructs PSBTv0 and PSBTv2 instances via createpsbt, injects unknown fields into global, input, and output maps, calls combinepsbt, and asserts that unknown fields are retained, merged, and deduplicated according to first-wins semantics. No production code is modified.
Changed components
test/functional/rpc_psbt.pyInspect captured patch +130 / −0
### test/functional/rpc_psbt.py
@@ -470,6 +470,134 @@ def tap_script(leaf_script, control_blocks):
tap_script(leaf_script_b, [control_block_with_longer_path]),
])
+ def test_combinepsbt_preserves_unknown_fields(self):
+ self.log.info("Test that combining PSBTs preserves unknown fields with the same and with distinct values per map.")
+
+ def unknown_key(key_type, key_data):
+ return bytes([key_type]) + key_data
+
+ def unknown_fields(*entries):
+ return {key.hex(): value.hex() for key, value in entries}
+
+ def build_psbt(key, global_value, input_value, output_value):
+ # A value of None leaves the corresponding map without the unknown field
+ psbt = PSBT.from_base64(base_psbt)
+ if global_value is not None:
+ psbt.g.map[key] = global_value
+ if input_value is not None:
+ psbt.i[0].map[key] = input_value
+ if output_value is not None:
+ psbt.o[0].map[key] = output_value
+ return psbt
+
+ unknown_key_a = unknown_key(0xf0, bytes.fromhex("010203040506070809"))
+ unknown_key_b = unknown_key(0xf0, bytes.fromhex("010203040506070810"))
+
+ # Distinct values per (psbt, map)
+ global_value_a = bytes.fromhex("0102030405060708090a0b0c0d0e0f")
+ global_value_b = bytes.fromhex("1112131415161718191a1b1c1d1e1f")
+ input_value_a = bytes.fromhex("2122232425262728292a2b2c2d2e2f")
+ input_value_b = bytes.fromhex("3132333435363738393a3b3c3d3e3f")
+ output_value_a = bytes.fromhex("4142434445464748494a4b4c4d4e4f")
+ output_value_b = bytes.fromhex("5152535455565758595a5b5c5d5e5f")
+
+ inputs = [{"txid": "ff" * 32, "vout": 0, "sequence": 0xffffffff}]
+ outputs = [{"data": "00"}]
+ for psbt_version in [0, 2]:
+ base_psbt = self.nodes[0].createpsbt(inputs=inputs, outputs=outputs, psbt_version=psbt_version)
+
+ # Combining the PSBTs with unknown keys and fields with the same values
+ combined_duplicated_psbt = self.nodes[0].combinepsbt([
+ build_psbt(unknown_key_a, global_value_a, global_value_a, global_value_a).to_base64(),
+ build_psbt(unknown_key_a, global_value_a, global_value_a, global_value_a).to_base64(),
+ ])
+ decoded = self.nodes[0].decodepsbt(combined_duplicated_psbt)
+ assert_equal(decoded["psbt_version"], psbt_version)
+ assert_equal(decoded["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a)
+ ))
+ assert_equal(decoded["inputs"][0]["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a)
+ ))
+ assert_equal(decoded["outputs"][0]["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a)
+ ))
+
+ # Combining PSBTs with the same unknown keys but distinct values (first PSBT wins).
+ combined_psbt_same_keys = self.nodes[0].combinepsbt([
+ build_psbt(unknown_key_a, global_value_a, global_value_a, global_value_a).to_base64(),
+ build_psbt(unknown_key_a, global_value_b, global_value_b, global_value_b).to_base64(),
+ ])
+ decoded = self.nodes[0].decodepsbt(combined_psbt_same_keys)
+ assert_equal(decoded["psbt_version"], psbt_version)
+ assert_equal(decoded["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a)
+ ))
+ assert_equal(decoded["inputs"][0]["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a)
+ ))
+ assert_equal(decoded["outputs"][0]["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a)
+ ))
+
+ # Combining PSBTs with unknown fields with the same values
+ combined_psbt_same_fields = self.nodes[0].combinepsbt([
+ build_psbt(unknown_key_a, global_value_a, global_value_a, global_value_a).to_base64(),
+ build_psbt(unknown_key_b, global_value_a, global_value_a, global_value_a).to_base64(),
+ ])
+ decoded = self.nodes[0].decodepsbt(combined_psbt_same_fields)
+ assert_equal(decoded["psbt_version"], psbt_version)
+ assert_equal(decoded["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a),
+ (unknown_key_b, global_value_a),
+ ))
+ assert_equal(decoded["inputs"][0]["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a),
+ (unknown_key_b, global_value_a),
+ ))
+ assert_equal(decoded["outputs"][0]["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a),
+ (unknown_key_b, global_value_a),
+ ))
+
+ # Combining PSBTs preserves unknown fields with distinct values
+ combined_psbt = self.nodes[0].combinepsbt([
+ build_psbt(unknown_key_a, global_value_a, input_value_a, output_value_a).to_base64(),
+ build_psbt(unknown_key_b, global_value_b, input_value_b, output_value_b).to_base64(),
+ ])
+ decoded = self.nodes[0].decodepsbt(combined_psbt)
+ assert_equal(decoded["psbt_version"], psbt_version)
+ assert_equal(decoded["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a),
+ (unknown_key_b, global_value_b),
+ ))
+ assert_equal(decoded["inputs"][0]["unknown"], unknown_fields(
+ (unknown_key_a, input_value_a),
+ (unknown_key_b, input_value_b),
+ ))
+ assert_equal(decoded["outputs"][0]["unknown"], unknown_fields(
+ (unknown_key_a, output_value_a),
+ (unknown_key_b, output_value_b),
+ ))
+
+ # Combining PSBTs with unknown fields missing from the maps of the other PSBT
+ # The fields of each map are preserved regardless of which PSBT they come from
+ combined_psbt = self.nodes[0].combinepsbt([
+ build_psbt(unknown_key_a, global_value_a, None, None).to_base64(),
+ build_psbt(unknown_key_a, None, input_value_b, output_value_b).to_base64(),
+ ])
+ decoded = self.nodes[0].decodepsbt(combined_psbt)
+ assert_equal(decoded["psbt_version"], psbt_version)
+ assert_equal(decoded["unknown"], unknown_fields(
+ (unknown_key_a, global_value_a)
+ ))
+ assert_equal(decoded["inputs"][0]["unknown"], unknown_fields(
+ (unknown_key_a, input_value_b)
+ ))
+ assert_equal(decoded["outputs"][0]["unknown"], unknown_fields(
+ (unknown_key_a, output_value_b)
+ ))
+
def test_sighash_mismatch(self):
self.log.info("Test sighash type mismatches")
self.nodes[0].createwallet("sighash_mismatch")
@@ -1569,6 +1697,8 @@ def global_xpub_key(extended_pubkey):
self.test_combinepsbt_global_xpub_origin_conflict()
self.test_combinepsbt_tap_leaf_script_conflict()
+ self.test_combinepsbt_preserves_unknown_fields()
+
self.log.info("Test that combining PSBTs with different transactions fails")
tx = CTransaction()
tx.vin = [CTxIn(outpoint=COutPoint(hash=int('aa' * 32, 16), n=0), scriptSig=b"")]Risk score
Our methodology →Why this scored 15/100
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