Merge bitcoin/bitcoin#28121: include verbose "reject-details" field in testmempoolaccept response

b6f0593 doc: add release note about testmempoolaccept debug-message (Matthew Zipkin)
f9cac63 test: cover testmempoolaccept debug-message in RBF test (Matthew Zipkin)
f9650e1 rbf: remove unecessary newline at end of error string (Matthew Zipkin)
221c789 rpc: include verbose reject-details field in testmempoolaccept response (Matthew Zipkin)

Pull request description:

  Adds a new field `reject-details` in `testmempoolaccept` responses to include `m_debug_message` from `ValidationState`. This string is the complete error message thrown by the mempool in response to `sendrawtransaction`.

  The extra verbosity is helpful to consumers of `testmempoolaccept`, which is sort of a debug tool anyway.

  example:
  >
  > {
  >   "txid": "07d7a59a7bdad4c3a5070659ea04147c9b755ad9e173c52b6a38e017abf0f5b8",
  >   "wtxid": "5dc243b1b92ee2f5a43134eb3e23449be03d1abb3d7f3c03c836ed0f13c50185",
  >   "allowed": false,
  >   "reject-reason": "insufficient fee",
  >   "reject-details": "insufficient fee, rejecting replacement 07d7a59a7bdad4c3a5070659ea04147c9b755ad9e173c52b6a38e017abf0f5b8; new feerate 0.00300000 BTC/kvB <= old feerate 0.00300000 BTC/kvB"
  > }

ACKs for top commit:
  rkrux:
    re-ACK b6f0593
  glozow:
    ACK b6f0593

Tree-SHA512: 340b8023d59cefa84598879c4efdb7c399a3f62da126e87c595523f302e53d33098fc69da9c5f8c92b7580dc75466c66cea372051f935b197265648fe15c43a3

Author: glozow

doc/release-notes-28121.md

@@ -0,0 +1,2 @@
+The RPC `testmempoolaccept` response now includes a "reject-details" field in some cases,
+similar to the complete error messages returned by `sendrawtransaction` (#28121)

src/policy/rbf.cpp

@@ -71,7 +71,7 @@ std::optional<std::string> GetEntriesForConflicts(const CTransaction& tx,
         // descendants (i.e. if multiple conflicts share a descendant, it will be counted multiple
         // times), but we just want to be conservative to avoid doing too much work.
         if (nConflictingCount > MAX_REPLACEMENT_CANDIDATES) {
-            return strprintf("rejecting replacement %s; too many potential replacements (%d > %d)\n",
+            return strprintf("rejecting replacement %s; too many potential replacements (%d > %d)",
                              txid.ToString(),
                              nConflictingCount,
                              MAX_REPLACEMENT_CANDIDATES);

src/rpc/mempool.cpp

@@ -146,7 +146,8 @@ static RPCHelpMan testmempoolaccept()
                             {RPCResult{RPCResult::Type::STR_HEX, "", "transaction wtxid in hex"},
                         }},
                     }},
-                    {RPCResult::Type::STR, "reject-reason", /*optional=*/true, "Rejection string (only present when 'allowed' is false)"},
+                    {RPCResult::Type::STR, "reject-reason", /*optional=*/true, "Rejection reason (only present when 'allowed' is false)"},
+                    {RPCResult::Type::STR, "reject-details", /*optional=*/true, "Rejection details (only present when 'allowed' is false and rejection details exist)"},
                 }},
             }
         },
@@ -245,6 +246,7 @@ static RPCHelpMan testmempoolaccept()
                         result_inner.pushKV("reject-reason", "missing-inputs");
                     } else {
                         result_inner.pushKV("reject-reason", state.GetRejectReason());
+                        result_inner.pushKV("reject-details", state.ToString());
                     }
                 }
                 rpc_result.push_back(std::move(result_inner));

test/functional/feature_cltv.py

@@ -148,6 +148,10 @@ def run_test(self):
         # create and test one invalid tx per CLTV failure reason (5 in total)
         for i in range(5):
             spendtx = wallet.create_self_transfer()['tx']
+            assert_equal(len(spendtx.vin), 1)
+            coin = spendtx.vin[0]
+            coin_txid = format(coin.prevout.hash, '064x')
+            coin_vout = coin.prevout.n
             cltv_invalidate(spendtx, i)
 
             expected_cltv_reject_reason = [
@@ -159,12 +163,15 @@ def run_test(self):
             ][i]
             # First we show that this tx is valid except for CLTV by getting it
             # rejected from the mempool for exactly that reason.
+            spendtx_txid = spendtx.hash
+            spendtx_wtxid = spendtx.getwtxid()
             assert_equal(
                 [{
-                    'txid': spendtx.hash,
-                    'wtxid': spendtx.getwtxid(),
+                    'txid': spendtx_txid,
+                    'wtxid': spendtx_wtxid,
                     'allowed': False,
                     'reject-reason': expected_cltv_reject_reason,
+                    'reject-details': expected_cltv_reject_reason + f", input 0 of {spendtx_txid} (wtxid {spendtx_wtxid}), spending {coin_txid}:{coin_vout}"
                 }],
                 self.nodes[0].testmempoolaccept(rawtxs=[spendtx.serialize().hex()], maxfeerate=0),
             )

test/functional/feature_dersig.py

@@ -109,18 +109,23 @@ def run_test(self):
         self.log.info("Test that transactions with non-DER signatures cannot appear in a block")
         block.nVersion = 4
 
-        spendtx = self.create_tx(self.coinbase_txids[1])
+        coin_txid = self.coinbase_txids[1]
+        spendtx = self.create_tx(coin_txid)
         unDERify(spendtx)
         spendtx.rehash()
 
         # First we show that this tx is valid except for DERSIG by getting it
         # rejected from the mempool for exactly that reason.
+        spendtx_txid = spendtx.hash
+        spendtx_wtxid = spendtx.getwtxid()
         assert_equal(
             [{
-                'txid': spendtx.hash,
-                'wtxid': spendtx.getwtxid(),
+                'txid': spendtx_txid,
+                'wtxid': spendtx_wtxid,
                 'allowed': False,
                 'reject-reason': 'mandatory-script-verify-flag-failed (Non-canonical DER signature)',
+                'reject-details': 'mandatory-script-verify-flag-failed (Non-canonical DER signature), ' +
+                                  f"input 0 of {spendtx_txid} (wtxid {spendtx_wtxid}), spending {coin_txid}:0"
             }],
             self.nodes[0].testmempoolaccept(rawtxs=[spendtx.serialize().hex()], maxfeerate=0),
         )

test/functional/feature_rbf.py

@@ -103,14 +103,22 @@ def test_simple_doublespend(self):
         """Simple doublespend"""
         # we use MiniWallet to create a transaction template with inputs correctly set,
         # and modify the output (amount, scriptPubKey) according to our needs
-        tx = self.wallet.create_self_transfer()["tx"]
+        tx = self.wallet.create_self_transfer(fee_rate=Decimal("0.003"))["tx"]
         tx1a_txid = self.nodes[0].sendrawtransaction(tx.serialize().hex())
 
         # Should fail because we haven't changed the fee
         tx.vout[0].scriptPubKey[-1] ^= 1
+        tx.rehash()
+        tx_hex = tx.serialize().hex()
 
         # This will raise an exception due to insufficient fee
-        assert_raises_rpc_error(-26, "insufficient fee", self.nodes[0].sendrawtransaction, tx.serialize().hex(), 0)
+        reject_reason = "insufficient fee"
+        reject_details = f"{reject_reason}, rejecting replacement {tx.hash}; new feerate 0.00300000 BTC/kvB <= old feerate 0.00300000 BTC/kvB"
+        res = self.nodes[0].testmempoolaccept(rawtxs=[tx_hex])[0]
+        assert_equal(res["reject-reason"], reject_reason)
+        assert_equal(res["reject-details"], reject_details)
+        assert_raises_rpc_error(-26, f"{reject_details}", self.nodes[0].sendrawtransaction, tx_hex, 0)
+
 
         # Extra 0.1 BTC fee
         tx.vout[0].nValue -= int(0.1 * COIN)
@@ -154,7 +162,14 @@ def test_doublespend_chain(self):
         dbl_tx_hex = dbl_tx.serialize().hex()
 
         # This will raise an exception due to insufficient fee
-        assert_raises_rpc_error(-26, "insufficient fee", self.nodes[0].sendrawtransaction, dbl_tx_hex, 0)
+        reject_reason = "insufficient fee"
+        reject_details = f"{reject_reason}, rejecting replacement {dbl_tx.hash}, less fees than conflicting txs; 3.00 < 4.00"
+        res = self.nodes[0].testmempoolaccept(rawtxs=[dbl_tx_hex])[0]
+        assert_equal(res["reject-reason"], reject_reason)
+        assert_equal(res["reject-details"], reject_details)
+        assert_raises_rpc_error(-26, f"{reject_details}", self.nodes[0].sendrawtransaction, dbl_tx_hex, 0)
+
+
 
         # Accepted with sufficient fee
         dbl_tx.vout[0].nValue = int(0.1 * COIN)
@@ -273,22 +288,30 @@ def test_spends_of_conflicting_outputs(self):
         utxo1 = self.make_utxo(self.nodes[0], int(1.2 * COIN))
         utxo2 = self.make_utxo(self.nodes[0], 3 * COIN)
 
-        tx1a_utxo = self.wallet.send_self_transfer(
+        tx1a = self.wallet.send_self_transfer(
             from_node=self.nodes[0],
             utxo_to_spend=utxo1,
             sequence=0,
             fee=Decimal("0.1"),
-        )["new_utxo"]
+        )
+        tx1a_utxo = tx1a["new_utxo"]
 
         # Direct spend an output of the transaction we're replacing.
-        tx2_hex = self.wallet.create_self_transfer_multi(
+        tx2 = self.wallet.create_self_transfer_multi(
             utxos_to_spend=[utxo1, utxo2, tx1a_utxo],
             sequence=0,
             amount_per_output=int(COIN * tx1a_utxo["value"]),
-        )["hex"]
+        )["tx"]
+        tx2_hex = tx2.serialize().hex()
 
         # This will raise an exception
-        assert_raises_rpc_error(-26, "bad-txns-spends-conflicting-tx", self.nodes[0].sendrawtransaction, tx2_hex, 0)
+        reject_reason = "bad-txns-spends-conflicting-tx"
+        reject_details = f"{reject_reason}, {tx2.hash} spends conflicting transaction {tx1a['tx'].hash}"
+        res = self.nodes[0].testmempoolaccept(rawtxs=[tx2_hex])[0]
+        assert_equal(res["reject-reason"], reject_reason)
+        assert_equal(res["reject-details"], reject_details)
+        assert_raises_rpc_error(-26, f"{reject_details}", self.nodes[0].sendrawtransaction, tx2_hex, 0)
+
 
         # Spend tx1a's output to test the indirect case.
         tx1b_utxo = self.wallet.send_self_transfer(
@@ -319,14 +342,21 @@ def test_new_unconfirmed_inputs(self):
             fee=Decimal("0.1"),
         )
 
-        tx2_hex = self.wallet.create_self_transfer_multi(
+        tx2 = self.wallet.create_self_transfer_multi(
             utxos_to_spend=[confirmed_utxo, unconfirmed_utxo],
             sequence=0,
             amount_per_output=1 * COIN,
-        )["hex"]
+        )["tx"]
+        tx2_hex = tx2.serialize().hex()
 
         # This will raise an exception
-        assert_raises_rpc_error(-26, "replacement-adds-unconfirmed", self.nodes[0].sendrawtransaction, tx2_hex, 0)
+        reject_reason = "replacement-adds-unconfirmed"
+        reject_details = f"{reject_reason}, replacement {tx2.hash} adds unconfirmed input, idx 1"
+        res = self.nodes[0].testmempoolaccept(rawtxs=[tx2_hex])[0]
+        assert_equal(res["reject-reason"], reject_reason)
+        assert_equal(res["reject-details"], reject_details)
+        assert_raises_rpc_error(-26, f"{reject_details}", self.nodes[0].sendrawtransaction, tx2_hex, 0)
+
 
     def test_too_many_replacements(self):
         """Replacements that evict too many transactions are rejected"""
@@ -368,7 +398,13 @@ def test_too_many_replacements(self):
         double_tx_hex = double_tx.serialize().hex()
 
         # This will raise an exception
-        assert_raises_rpc_error(-26, "too many potential replacements", self.nodes[0].sendrawtransaction, double_tx_hex, 0)
+        reject_reason = "too many potential replacements"
+        reject_details = f"{reject_reason}, rejecting replacement {double_tx.hash}; too many potential replacements ({MAX_REPLACEMENT_LIMIT + 1} > {MAX_REPLACEMENT_LIMIT})"
+        res = self.nodes[0].testmempoolaccept(rawtxs=[double_tx_hex])[0]
+        assert_equal(res["reject-reason"], reject_reason)
+        assert_equal(res["reject-details"], reject_details)
+        assert_raises_rpc_error(-26, f"{reject_details}", self.nodes[0].sendrawtransaction, double_tx_hex, 0)
+
 
         # If we remove an input, it should pass
         double_tx.vin.pop()

test/functional/mempool_accept.py

@@ -67,6 +67,8 @@ def check_mempool_result(self, result_expected, *args, **kwargs):
             if "fees" in r:
                 r["fees"].pop("effective-feerate")
                 r["fees"].pop("effective-includes")
+            if "reject-details" in r:
+                r.pop("reject-details")
         assert_equal(result_expected, result_test)
         assert_equal(self.nodes[0].getmempoolinfo()['size'], self.mempool_size)  # Must not change mempool state
 

test/functional/mempool_accept_wtxid.py

@@ -100,13 +100,15 @@ def run_test(self):
             "txid": child_one_txid,
             "wtxid": child_one_wtxid,
             "allowed": False,
-            "reject-reason": "txn-already-in-mempool"
+            "reject-reason": "txn-already-in-mempool",
+            "reject-details": "txn-already-in-mempool"
         }])
         assert_equal(node.testmempoolaccept([child_two.serialize().hex()])[0], {
             "txid": child_two_txid,
             "wtxid": child_two_wtxid,
             "allowed": False,
-            "reject-reason": "txn-same-nonwitness-data-in-mempool"
+            "reject-reason": "txn-same-nonwitness-data-in-mempool",
+            "reject-details": "txn-same-nonwitness-data-in-mempool"
         })
 
         # sendrawtransaction will not throw but quits early when the exact same transaction is already in mempool

test/functional/mempool_package_rbf.py

@@ -219,7 +219,7 @@ def test_package_rbf_max_conflicts(self):
         package_child = self.wallet.create_self_transfer(fee_rate=child_feerate, utxo_to_spend=package_parent["new_utxos"][0])
 
         pkg_results = node.submitpackage([package_parent["hex"], package_child["hex"]], maxfeerate=0)
-        assert_equal(f"package RBF failed: too many potential replacements, rejecting replacement {package_child['tx'].rehash()}; too many potential replacements (102 > 100)\n", pkg_results["package_msg"])
+        assert_equal(f"package RBF failed: too many potential replacements, rejecting replacement {package_child['tx'].rehash()}; too many potential replacements (102 > 100)", pkg_results["package_msg"])
         self.assert_mempool_contents(expected=expected_txns)
 
         # Make singleton tx to conflict with in next batch
@@ -234,7 +234,7 @@ def test_package_rbf_max_conflicts(self):
         package_parent = self.wallet.create_self_transfer_multi(utxos_to_spend=double_spending_coins, fee_per_output=parent_fee_per_conflict)
         package_child = self.wallet.create_self_transfer(fee_rate=child_feerate, utxo_to_spend=package_parent["new_utxos"][0])
         pkg_results = node.submitpackage([package_parent["hex"], package_child["hex"]], maxfeerate=0)
-        assert_equal(f"package RBF failed: too many potential replacements, rejecting replacement {package_child['tx'].rehash()}; too many potential replacements (101 > 100)\n", pkg_results["package_msg"])
+        assert_equal(f"package RBF failed: too many potential replacements, rejecting replacement {package_child['tx'].rehash()}; too many potential replacements (101 > 100)", pkg_results["package_msg"])
         self.assert_mempool_contents(expected=expected_txns)
 
         # Finally, evict MAX_REPLACEMENT_CANDIDATES

test/functional/rpc_packages.py

@@ -110,17 +110,21 @@ def test_independent(self, coin):
         self.assert_testres_equal(package_bad, testres_bad)
 
         self.log.info("Check testmempoolaccept tells us when some transactions completed validation successfully")
-        tx_bad_sig_hex = node.createrawtransaction([{"txid": coin["txid"], "vout": 0}],
+        tx_bad_sig_hex = node.createrawtransaction([{"txid": coin["txid"], "vout": coin["vout"]}],
                                            {address : coin["amount"] - Decimal("0.0001")})
         tx_bad_sig = tx_from_hex(tx_bad_sig_hex)
         testres_bad_sig = node.testmempoolaccept(self.independent_txns_hex + [tx_bad_sig_hex])
         # By the time the signature for the last transaction is checked, all the other transactions
         # have been fully validated, which is why the node returns full validation results for all
         # transactions here but empty results in other cases.
+        tx_bad_sig_txid = tx_bad_sig.rehash()
+        tx_bad_sig_wtxid = tx_bad_sig.getwtxid()
         assert_equal(testres_bad_sig, self.independent_txns_testres + [{
-            "txid": tx_bad_sig.rehash(),
-            "wtxid": tx_bad_sig.getwtxid(), "allowed": False,
-            "reject-reason": "mandatory-script-verify-flag-failed (Operation not valid with the current stack size)"
+            "txid": tx_bad_sig_txid,
+            "wtxid": tx_bad_sig_wtxid, "allowed": False,
+            "reject-reason": "mandatory-script-verify-flag-failed (Operation not valid with the current stack size)",
+            "reject-details": "mandatory-script-verify-flag-failed (Operation not valid with the current stack size), " +
+                              f"input 0 of {tx_bad_sig_txid} (wtxid {tx_bad_sig_wtxid}), spending {coin['txid']}:{coin['vout']}"
         }])
 
         self.log.info("Check testmempoolaccept reports txns in packages that exceed max feerate")
@@ -304,7 +308,8 @@ def test_rbf(self):
         assert testres_rbf_single[0]["allowed"]
         testres_rbf_package = self.independent_txns_testres_blank + [{
             "txid": replacement_tx["txid"], "wtxid": replacement_tx["wtxid"], "allowed": False,
-            "reject-reason": "bip125-replacement-disallowed"
+            "reject-reason": "bip125-replacement-disallowed",
+            "reject-details": "bip125-replacement-disallowed"
         }]
         self.assert_testres_equal(self.independent_txns_hex + [replacement_tx["hex"]], testres_rbf_package)