Merge #13317: [0.16.1] Remaining backports

08334b73be031485a41e2c0647c2df1aa13c6316 qa: Pad scriptPubKeys to get minimum sized txs (MarcoFalke)
0a000b9b73a7d7bb4086aeefc86841d0fc33e652 Policy to reject extremely small transactions (Johnson Lau)
1fffc2b346b2d2e129db5c9f5cad00e820c85c45 Add transaction tests for constant scriptCode (Johnson Lau)
d353dd121be0bf2a525e4bbea2b4ada2954d2b15 Add constant scriptCode policy in non-segwit scripts (Johnson Lau)
d6c3a08c482225b3742c9145a9cbfe60567f0c4f Add unit tests for signals generated by ProcessNewBlock() (Jesse Cohen)
bb79aaf93af93d5f9f5097cff4fbb2791af86875 Fix concurrency-related bugs in ActivateBestChain (Jesse Cohen)
0948153ea62ff4921daef326da0fddb8425cd866 Do not unlock cs_main in ABC unless we've actually made progress. (Matt Corallo)
c71e535aec5aaef04764238a94e456f2405adbb5 Bugfix: ensure consistency of m_failed_blocks after reconsiderblock (Suhas Daftuar)

Pull request description:

Tree-SHA512: 7466b8fcc2a1d598102028019d82c581fe985a11679d002c430287851142598c9172249aa9de511a26bd4c92dc4891b5ab597c24af4f591f2158cc2a58ff7beb

22 files changed, 384 insertions, 80 deletions

diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index d4d972b2bb..bd364a8338 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -83,9 +83,10 @@ BITCOIN_TESTS =\
   test/transaction_tests.cpp \
   test/txvalidation_tests.cpp \
   test/txvalidationcache_tests.cpp \
-  test/versionbits_tests.cpp \
   test/uint256_tests.cpp \
-  test/util_tests.cpp
+  test/util_tests.cpp \
+  test/validation_block_tests.cpp \
+  test/versionbits_tests.cpp
 
 if ENABLE_WALLET
 BITCOIN_TESTS += \
diff --git a/src/policy/policy.h b/src/policy/policy.h
index 3d96406bbc..be1c0e03ec 100644
--- a/src/policy/policy.h
+++ b/src/policy/policy.h
@@ -22,6 +22,8 @@ static const unsigned int DEFAULT_BLOCK_MAX_WEIGHT = MAX_BLOCK_WEIGHT - 4000;
 static const unsigned int DEFAULT_BLOCK_MIN_TX_FEE = 1000;
 /** The maximum weight for transactions we're willing to relay/mine */
 static const unsigned int MAX_STANDARD_TX_WEIGHT = 400000;
+/** The minimum non-witness size for transactions we're willing to relay/mine (1 segwit input + 1 P2WPKH output = 82 bytes) */
+static const unsigned int MIN_STANDARD_TX_NONWITNESS_SIZE = 82;
 /** Maximum number of signature check operations in an IsStandard() P2SH script */
 static const unsigned int MAX_P2SH_SIGOPS = 15;
 /** The maximum number of sigops we're willing to relay/mine in a single tx */
@@ -63,7 +65,8 @@ static constexpr unsigned int STANDARD_SCRIPT_VERIFY_FLAGS = MANDATORY_SCRIPT_VE
                                                              SCRIPT_VERIFY_LOW_S |
                                                              SCRIPT_VERIFY_WITNESS |
                                                              SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM |
-                                                             SCRIPT_VERIFY_WITNESS_PUBKEYTYPE;
+                                                             SCRIPT_VERIFY_WITNESS_PUBKEYTYPE |
+                                                             SCRIPT_VERIFY_CONST_SCRIPTCODE;
 
 /** For convenience, standard but not mandatory verify flags. */
 static constexpr unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS = STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS;
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 2cdff7ee57..8b26caef5d 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -306,6 +306,10 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
                 opcode == OP_RSHIFT)
                 return set_error(serror, SCRIPT_ERR_DISABLED_OPCODE); // Disabled opcodes.
 
+            // With SCRIPT_VERIFY_CONST_SCRIPTCODE, OP_CODESEPARATOR in non-segwit script is rejected even in an unexecuted branch
+            if (opcode == OP_CODESEPARATOR && sigversion == SIGVERSION_BASE && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE))
+                return set_error(serror, SCRIPT_ERR_OP_CODESEPARATOR);
+
             if (fExec && 0 <= opcode && opcode <= OP_PUSHDATA4) {
                 if (fRequireMinimal && !CheckMinimalPush(vchPushValue, opcode)) {
                     return set_error(serror, SCRIPT_ERR_MINIMALDATA);
@@ -869,6 +873,9 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
 
                 case OP_CODESEPARATOR:
                 {
+                    // If SCRIPT_VERIFY_CONST_SCRIPTCODE flag is set, use of OP_CODESEPARATOR is rejected in pre-segwit
+                    // script, even in an unexecuted branch (this is checked above the opcode case statement).
+
                     // Hash starts after the code separator
                     pbegincodehash = pc;
                 }
@@ -889,7 +896,9 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
 
                     // Drop the signature in pre-segwit scripts but not segwit scripts
                     if (sigversion == SIGVERSION_BASE) {
-                        scriptCode.FindAndDelete(CScript(vchSig));
+                        int found = scriptCode.FindAndDelete(CScript(vchSig));
+                        if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE))
+                            return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE);
                     }
 
                     if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) {
@@ -953,7 +962,9 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
                     {
                         valtype& vchSig = stacktop(-isig-k);
                         if (sigversion == SIGVERSION_BASE) {
-                            scriptCode.FindAndDelete(CScript(vchSig));
+                            int found = scriptCode.FindAndDelete(CScript(vchSig));
+                            if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE))
+                                return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE);
                         }
                     }
 
diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index e12329be76..edb55cc458 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -111,6 +111,10 @@ enum
     // Public keys in segregated witness scripts must be compressed
     //
     SCRIPT_VERIFY_WITNESS_PUBKEYTYPE = (1U << 15),
+
+    // Making OP_CODESEPARATOR and FindAndDelete fail any non-segwit scripts
+    //
+    SCRIPT_VERIFY_CONST_SCRIPTCODE = (1U << 16),
 };
 
 bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror);
diff --git a/src/script/script_error.cpp b/src/script/script_error.cpp
index dbceb1f740..ceda740580 100644
--- a/src/script/script_error.cpp
+++ b/src/script/script_error.cpp
@@ -89,6 +89,10 @@ const char* ScriptErrorString(const ScriptError serror)
             return "Witness provided for non-witness script";
         case SCRIPT_ERR_WITNESS_PUBKEYTYPE:
             return "Using non-compressed keys in segwit";
+        case SCRIPT_ERR_OP_CODESEPARATOR:
+            return "Using OP_CODESEPARATOR in non-witness script";
+        case SCRIPT_ERR_SIG_FINDANDDELETE:
+            return "Signature is found in scriptCode";
         case SCRIPT_ERR_UNKNOWN_ERROR:
         case SCRIPT_ERR_ERROR_COUNT:
         default: break;
diff --git a/src/script/script_error.h b/src/script/script_error.h
index 3200e94707..6982a087f4 100644
--- a/src/script/script_error.h
+++ b/src/script/script_error.h
@@ -64,6 +64,10 @@ typedef enum ScriptError_t
     SCRIPT_ERR_WITNESS_UNEXPECTED,
     SCRIPT_ERR_WITNESS_PUBKEYTYPE,
 
+    /* Constant scriptCode */
+    SCRIPT_ERR_OP_CODESEPARATOR,
+    SCRIPT_ERR_SIG_FINDANDDELETE,
+
     SCRIPT_ERR_ERROR_COUNT
 } ScriptError;
 
diff --git a/src/test/data/tx_invalid.json b/src/test/data/tx_invalid.json
index 09442b7f9f..0756c4e635 100644
--- a/src/test/data/tx_invalid.json
+++ b/src/test/data/tx_invalid.json
@@ -340,5 +340,53 @@
 [[["9628667ad48219a169b41b020800162287d2c0f713c04157e95c484a8dcb7592", 7500, "0x00 0x20 0x9b66c15b4e0b4eb49fa877982cafded24859fe5b0e2dbfbe4f0df1de7743fd52", 200000]],
 "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", "P2SH,WITNESS"],
 
+["SCRIPT_VERIFY_CONST_SCRIPTCODE tests"],
+["All transactions are copied from OP_CODESEPARATOR tests in tx_valid.json"],
+
+[[["bc7fd132fcf817918334822ee6d9bd95c889099c96e07ca2c1eb2cc70db63224", 0, "CODESEPARATOR 0x21 0x038479a0fa998cd35259a2ef0a7a5c68662c1474f88ccb6d08a7677bbec7f22041 CHECKSIG"]],
+  "01000000012432b60dc72cebc1a27ce0969c0989c895bdd9e62e8234839117f8fc32d17fbc000000004a493046022100a576b52051962c25e642c0fd3d77ee6c92487048e5d90818bcf5b51abaccd7900221008204f8fb121be4ec3b24483b1f92d89b1b0548513a134e345c5442e86e8617a501ffffffff010000000000000000016a00000000", "P2SH,CONST_SCRIPTCODE"],
+[[["83e194f90b6ef21fa2e3a365b63794fb5daa844bdc9b25de30899fcfe7b01047", 0, "CODESEPARATOR CODESEPARATOR 0x21 0x038479a0fa998cd35259a2ef0a7a5c68662c1474f88ccb6d08a7677bbec7f22041 CHECKSIG"]],
+  "01000000014710b0e7cf9f8930de259bdc4b84aa5dfb9437b665a3e3a21ff26e0bf994e183000000004a493046022100a166121a61b4eeb19d8f922b978ff6ab58ead8a5a5552bf9be73dc9c156873ea02210092ad9bc43ee647da4f6652c320800debcf08ec20a094a0aaf085f63ecb37a17201ffffffff010000000000000000016a00000000", "P2SH,CONST_SCRIPTCODE"],
+
+[[["326882a7f22b5191f1a0cc9962ca4b878cd969cf3b3a70887aece4d801a0ba5e", 0, "0x21 0x038479a0fa998cd35259a2ef0a7a5c68662c1474f88ccb6d08a7677bbec7f22041 CODESEPARATOR CHECKSIG"]],
+  "01000000015ebaa001d8e4ec7a88703a3bcf69d98c874bca6299cca0f191512bf2a7826832000000004948304502203bf754d1c6732fbf87c5dcd81258aefd30f2060d7bd8ac4a5696f7927091dad1022100f5bcb726c4cf5ed0ed34cc13dadeedf628ae1045b7cb34421bc60b89f4cecae701ffffffff010000000000000000016a00000000", "P2SH,CONST_SCRIPTCODE"],
+
+[[["a955032f4d6b0c9bfe8cad8f00a8933790b9c1dc28c82e0f48e75b35da0e4944", 0, "0x21 0x038479a0fa998cd35259a2ef0a7a5c68662c1474f88ccb6d08a7677bbec7f22041 CHECKSIGVERIFY CODESEPARATOR 0x21 0x038479a0fa998cd35259a2ef0a7a5c68662c1474f88ccb6d08a7677bbec7f22041 CHECKSIGVERIFY CODESEPARATOR 1"]],
+  "010000000144490eda355be7480f2ec828dcc1b9903793a8008fad8cfe9b0c6b4d2f0355a900000000924830450221009c0a27f886a1d8cb87f6f595fbc3163d28f7a81ec3c4b252ee7f3ac77fd13ffa02203caa8dfa09713c8c4d7ef575c75ed97812072405d932bd11e6a1593a98b679370148304502201e3861ef39a526406bad1e20ecad06be7375ad40ddb582c9be42d26c3a0d7b240221009d0a3985e96522e59635d19cc4448547477396ce0ef17a58e7d74c3ef464292301ffffffff010000000000000000016a00000000", "P2SH,CONST_SCRIPTCODE"],
+
+["CODESEPARATOR in an unexecuted IF block is still invalid"],
+[[["a955032f4d6b0c9bfe8cad8f00a8933790b9c1dc28c82e0f48e75b35da0e4944", 0, "IF CODESEPARATOR ENDIF 0x21 0x0378d430274f8c5ec1321338151e9f27f4c676a008bdf8638d07c0b6be9ab35c71 CHECKSIGVERIFY CODESEPARATOR 1"]],
+  "010000000144490eda355be7480f2ec828dcc1b9903793a8008fad8cfe9b0c6b4d2f0355a9000000004a48304502207a6974a77c591fa13dff60cabbb85a0de9e025c09c65a4b2285e47ce8e22f761022100f0efaac9ff8ac36b10721e0aae1fb975c90500b50c56e8a0cc52b0403f0425dd0100ffffffff010000000000000000016a00000000", "P2SH,CONST_SCRIPTCODE"],
+
+["CODESEPARATOR in an executed IF block is invalid"],
+[[["a955032f4d6b0c9bfe8cad8f00a8933790b9c1dc28c82e0f48e75b35da0e4944", 0, "IF CODESEPARATOR ENDIF 0x21 0x0378d430274f8c5ec1321338151e9f27f4c676a008bdf8638d07c0b6be9ab35c71 CHECKSIGVERIFY CODESEPARATOR 1"]],
+  "010000000144490eda355be7480f2ec828dcc1b9903793a8008fad8cfe9b0c6b4d2f0355a9000000004a483045022100fa4a74ba9fd59c59f46c3960cf90cbe0d2b743c471d24a3d5d6db6002af5eebb02204d70ec490fd0f7055a7c45f86514336e3a7f03503dacecabb247fc23f15c83510151ffffffff010000000000000000016a00000000", "P2SH,CONST_SCRIPTCODE"],
+
+
+["Using CHECKSIG with singatures in scriptSigs will trigger FindAndDelete, which is invalid"],
+[[["ccf7f4053a02e653c36ac75c891b7496d0dc5ce5214f6c913d9cf8f1329ebee0", 0, "DUP HASH160 0x14 0xee5a6aa40facefb2655ac23c0c28c57c65c41f9b EQUALVERIFY CHECKSIG"]],
+  "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", "P2SH,CONST_SCRIPTCODE"],
+
+["OP_CODESEPARATOR in scriptSig is invalid"],
+[[["10c9f0effe83e97f80f067de2b11c6a00c3088a4bce42c5ae761519af9306f3c", 1, "DUP HASH160 0x14 0xee5a6aa40facefb2655ac23c0c28c57c65c41f9b EQUALVERIFY CHECKSIG"]],
+  "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", "P2SH,CONST_SCRIPTCODE"],
+
+["Again, FindAndDelete() in scriptSig"],
+[[["6056ebd549003b10cbbd915cea0d82209fe40b8617104be917a26fa92cbe3d6f", 0, "DUP HASH160 0x14 0xee5a6aa40facefb2655ac23c0c28c57c65c41f9b EQUALVERIFY CHECKSIG"]],
+  "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", "P2SH,CONST_SCRIPTCODE"],
+
+[[["5a6b0021a6042a686b6b94abc36b387bef9109847774e8b1e51eb8cc55c53921", 1, "DUP HASH160 0x14 0xee5a6aa40facefb2655ac23c0c28c57c65c41f9b EQUALVERIFY CHECKSIG"]],
+  "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", "P2SH,CONST_SCRIPTCODE"],
+
+["FindAndDelete() in redeemScript"],
+[[["b5b598de91787439afd5938116654e0b16b7a0d0f82742ba37564219c5afcbf9", 0, "DUP HASH160 0x14 0xf6f365c40f0739b61de827a44751e5e99032ed8f EQUALVERIFY CHECKSIG"],
+  ["ab9805c6d57d7070d9a42c5176e47bb705023e6b67249fb6760880548298e742", 0, "HASH160 0x14 0xd8dacdadb7462ae15cd906f1878706d0da8660e6 EQUAL"]],
+  "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", "P2SH,CONST_SCRIPTCODE"],
+
+["FindAndDelete() in bare CHECKMULTISIG"],
+[[["ceafe58e0f6e7d67c0409fbbf673c84c166e3c5d3c24af58f7175b18df3bb3db", 0, "DUP HASH160 0x14 0xf6f365c40f0739b61de827a44751e5e99032ed8f EQUALVERIFY CHECKSIG"],
+  ["ceafe58e0f6e7d67c0409fbbf673c84c166e3c5d3c24af58f7175b18df3bb3db", 1, "2 0x48 0x3045022015bd0139bcccf990a6af6ec5c1c52ed8222e03a0d51c334df139968525d2fcd20221009f9efe325476eb64c3958e4713e9eefe49bf1d820ed58d2112721b134e2a1a5303 0x21 0x0378d430274f8c5ec1321338151e9f27f4c676a008bdf8638d07c0b6be9ab35c71 0x21 0x0378d430274f8c5ec1321338151e9f27f4c676a008bdf8638d07c0b6be9ab35c71 3 CHECKMULTISIG"]],
+  "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", "P2SH,CONST_SCRIPTCODE"],
+
 ["Make diffs cleaner by leaving a comment here without comma at the end"]
 ]
diff --git a/src/test/data/tx_valid.json b/src/test/data/tx_valid.json
index a845083636..8c3952215f 100644
--- a/src/test/data/tx_valid.json
+++ b/src/test/data/tx_valid.json
@@ -477,17 +477,17 @@
 ["BIP143 example: P2WSH with OP_CODESEPARATOR and out-of-range SIGHASH_SINGLE."],
 [[["6eb316926b1c5d567cd6f5e6a84fec606fc53d7b474526d1fff3948020c93dfe", 0, "0x21 0x036d5c20fa14fb2f635474c1dc4ef5909d4568e5569b79fc94d3448486e14685f8 CHECKSIG", 156250000],
 ["f825690aee1b3dc247da796cacb12687a5e802429fd291cfd63e010f02cf1508", 0, "0x00 0x20 0x5d1b56b63d714eebe542309525f484b7e9d6f686b3781b6f61ef925d66d6f6a0", 4900000000]],
-"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", "P2SH,WITNESS"],
+"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", "P2SH,WITNESS,CONST_SCRIPTCODE"],
 
 ["BIP143 example: P2WSH with unexecuted OP_CODESEPARATOR and SINGLE|ANYONECANPAY"],
 [[["01c0cf7fba650638e55eb91261b183251fbb466f90dff17f10086817c542b5e9", 0, "0x00 0x20 0xba468eea561b26301e4cf69fa34bde4ad60c81e70f059f045ca9a79931004a4d", 16777215],
 ["1b2a9a426ba603ba357ce7773cb5805cb9c7c2b386d100d1fc9263513188e680", 0, "0x00 0x20 0xd9bbfbe56af7c4b7f960a70d7ea107156913d9e5a26b0a71429df5e097ca6537", 16777215]],
-"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", "P2SH,WITNESS"],
+"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", "P2SH,WITNESS,CONST_SCRIPTCODE"],
 
 ["BIP143 example: Same as the previous example with input-output pairs swapped"],
 [[["1b2a9a426ba603ba357ce7773cb5805cb9c7c2b386d100d1fc9263513188e680", 0, "0x00 0x20 0xd9bbfbe56af7c4b7f960a70d7ea107156913d9e5a26b0a71429df5e097ca6537", 16777215],
 ["01c0cf7fba650638e55eb91261b183251fbb466f90dff17f10086817c542b5e9", 0, "0x00 0x20 0xba468eea561b26301e4cf69fa34bde4ad60c81e70f059f045ca9a79931004a4d", 16777215]],
-"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", "P2SH,WITNESS"],
+"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", "P2SH,WITNESS,CONST_SCRIPTCODE"],
 
 ["BIP143 example: P2SH-P2WSH 6-of-6 multisig signed with 6 different SIGHASH types"],
 [[["6eb98797a21c6c10aa74edf29d618be109f48a8e94c694f3701e08ca69186436", 1, "HASH160 0x14 0x9993a429037b5d912407a71c252019287b8d27a5 EQUAL", 987654321]],
@@ -504,7 +504,7 @@
 "010000000169c12106097dc2e0526493ef67f21269fe888ef05c7a3a5dacab38e1ac8387f1581b0000b64830450220487fb382c4974de3f7d834c1b617fe15860828c7f96454490edd6d891556dcc9022100baf95feb48f845d5bfc9882eb6aeefa1bc3790e39f59eaa46ff7f15ae626c53e0121037a3fb04bcdb09eba90f69961ba1692a3528e45e67c85b200df820212d7594d334aad4830450220487fb382c4974de3f7d834c1b617fe15860828c7f96454490edd6d891556dcc9022100baf95feb48f845d5bfc9882eb6aeefa1bc3790e39f59eaa46ff7f15ae626c53e01ffffffff0101000000000000000000000000", "P2SH,WITNESS"],
 ["BIP143: correct sighash (without FindAndDelete) = 71c9cd9b2869b9c70b01b1f0360c148f42dee72297db312638df136f43311f23"],
 [[["f18783ace138abac5d3a7a5cf08e88fe6912f267ef936452e0c27d090621c169", 7500, "0x00 0x20 0x9e1be07558ea5cc8e02ed1d80c0911048afad949affa36d5c3951e3159dbea19", 200000]],
-"0100000000010169c12106097dc2e0526493ef67f21269fe888ef05c7a3a5dacab38e1ac8387f14c1d000000ffffffff01010000000000000000034830450220487fb382c4974de3f7d834c1b617fe15860828c7f96454490edd6d891556dcc9022100baf95feb48f845d5bfc9882eb6aeefa1bc3790e39f59eaa46ff7f15ae626c53e012102a9781d66b61fb5a7ef00ac5ad5bc6ffc78be7b44a566e3c87870e1079368df4c4aad4830450220487fb382c4974de3f7d834c1b617fe15860828c7f96454490edd6d891556dcc9022100baf95feb48f845d5bfc9882eb6aeefa1bc3790e39f59eaa46ff7f15ae626c53e0100000000", "P2SH,WITNESS"],
+"0100000000010169c12106097dc2e0526493ef67f21269fe888ef05c7a3a5dacab38e1ac8387f14c1d000000ffffffff01010000000000000000034830450220487fb382c4974de3f7d834c1b617fe15860828c7f96454490edd6d891556dcc9022100baf95feb48f845d5bfc9882eb6aeefa1bc3790e39f59eaa46ff7f15ae626c53e012102a9781d66b61fb5a7ef00ac5ad5bc6ffc78be7b44a566e3c87870e1079368df4c4aad4830450220487fb382c4974de3f7d834c1b617fe15860828c7f96454490edd6d891556dcc9022100baf95feb48f845d5bfc9882eb6aeefa1bc3790e39f59eaa46ff7f15ae626c53e0100000000", "P2SH,WITNESS,CONST_SCRIPTCODE"],
 ["This is multisig version of the FindAndDelete tests"],
 ["Script is 2 CHECKMULTISIGVERIFY <sig1> <sig2> DROP"],
 ["52af4830450220487fb382c4974de3f7d834c1b617fe15860828c7f96454490edd6d891556dcc9022100baf95feb48f845d5bfc9882eb6aeefa1bc3790e39f59eaa46ff7f15ae626c53e0148304502205286f726690b2e9b0207f0345711e63fa7012045b9eb0f19c2458ce1db90cf43022100e89f17f86abc5b149eba4115d4f128bcf45d77fb3ecdd34f594091340c0395960175"],
@@ -514,7 +514,7 @@
 "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", "P2SH,WITNESS"],
 ["BIP143: correct sighash (without FindAndDelete) = c1628a1e7c67f14ca0c27c06e4fdeec2e6d1a73c7a91d7c046ff83e835aebb72"],
 [[["9628667ad48219a169b41b020800162287d2c0f713c04157e95c484a8dcb7592", 7500, "0x00 0x20 0x9b66c15b4e0b4eb49fa877982cafded24859fe5b0e2dbfbe4f0df1de7743fd52", 200000]],
-"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", "P2SH,WITNESS"],
+"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", "P2SH,WITNESS,CONST_SCRIPTCODE"],
 
 ["Make diffs cleaner by leaving a comment here without comma at the end"]
 ]
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index c7a497f3a7..a6663e11d7 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -97,6 +97,8 @@ static ScriptErrorDesc script_errors[]={
     {SCRIPT_ERR_WITNESS_MALLEATED_P2SH, "WITNESS_MALLEATED_P2SH"},
     {SCRIPT_ERR_WITNESS_UNEXPECTED, "WITNESS_UNEXPECTED"},
     {SCRIPT_ERR_WITNESS_PUBKEYTYPE, "WITNESS_PUBKEYTYPE"},
+    {SCRIPT_ERR_OP_CODESEPARATOR, "OP_CODESEPARATOR"},
+    {SCRIPT_ERR_SIG_FINDANDDELETE, "SIG_FINDANDDELETE"},
 };
 
 const char *FormatScriptError(ScriptError_t err)
diff --git a/src/test/test_bitcoin.cpp b/src/test/test_bitcoin.cpp
index bdd44489f4..82944ffed5 100644
--- a/src/test/test_bitcoin.cpp
+++ b/src/test/test_bitcoin.cpp
@@ -37,6 +37,12 @@ FastRandomContext insecure_rand_ctx(insecure_rand_seed);
 extern bool fPrintToConsole;
 extern void noui_connect();
 
+std::ostream& operator<<(std::ostream& os, const uint256& num)
+{
+    os << num.ToString();
+    return os;
+}
+
 BasicTestingSetup::BasicTestingSetup(const std::string& chainName)
 {
         SHA256AutoDetect();
diff --git a/src/test/test_bitcoin.h b/src/test/test_bitcoin.h
index 944835cccf..234315dbca 100644
--- a/src/test/test_bitcoin.h
+++ b/src/test/test_bitcoin.h
@@ -118,4 +118,7 @@ struct TestMemPoolEntryHelper
 
 CBlock getBlock13b8a();
 
+// define an implicit conversion here so that uint256 may be used directly in BOOST_CHECK_*
+std::ostream& operator<<(std::ostream& os, const uint256& num);
+
 #endif
diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index edfb35d155..0c6f100ce3 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -53,6 +53,7 @@ static std::map<std::string, unsigned int> mapFlagNames = {
     {std::string("WITNESS"), (unsigned int)SCRIPT_VERIFY_WITNESS},
     {std::string("DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM"), (unsigned int)SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM},
     {std::string("WITNESS_PUBKEYTYPE"), (unsigned int)SCRIPT_VERIFY_WITNESS_PUBKEYTYPE},
+    {std::string("CONST_SCRIPTCODE"), (unsigned int)SCRIPT_VERIFY_CONST_SCRIPTCODE},
 };
 
 unsigned int ParseScriptFlags(std::string strFlags)
diff --git a/src/test/validation_block_tests.cpp b/src/test/validation_block_tests.cpp
new file mode 100644
index 0000000000..f835570168
--- /dev/null
+++ b/src/test/validation_block_tests.cpp
@@ -0,0 +1,184 @@
+// Copyright (c) 2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <boost/test/unit_test.hpp>
+
+#include <chainparams.h>
+#include <consensus/merkle.h>
+#include <consensus/validation.h>
+#include <miner.h>
+#include <pow.h>
+#include <random.h>
+#include <test/test_bitcoin.h>
+#include <validation.h>
+#include <validationinterface.h>
+
+struct RegtestingSetup : public TestingSetup {
+    RegtestingSetup() : TestingSetup(CBaseChainParams::REGTEST) {}
+};
+
+BOOST_FIXTURE_TEST_SUITE(validation_block_tests, RegtestingSetup)
+
+struct TestSubscriber : public CValidationInterface {
+    uint256 m_expected_tip;
+
+    TestSubscriber(uint256 tip) : m_expected_tip(tip) {}
+
+    void UpdatedBlockTip(const CBlockIndex* pindexNew, const CBlockIndex* pindexFork, bool fInitialDownload)
+    {
+        BOOST_CHECK_EQUAL(m_expected_tip, pindexNew->GetBlockHash());
+    }
+
+    void BlockConnected(const std::shared_ptr<const CBlock>& block, const CBlockIndex* pindex, const std::vector<CTransactionRef>& txnConflicted)
+    {
+        BOOST_CHECK_EQUAL(m_expected_tip, block->hashPrevBlock);
+        BOOST_CHECK_EQUAL(m_expected_tip, pindex->pprev->GetBlockHash());
+
+        m_expected_tip = block->GetHash();
+    }
+
+    void BlockDisconnected(const std::shared_ptr<const CBlock>& block)
+    {
+        BOOST_CHECK_EQUAL(m_expected_tip, block->GetHash());
+
+        m_expected_tip = block->hashPrevBlock;
+    }
+};
+
+std::shared_ptr<CBlock> Block(const uint256& prev_hash)
+{
+    static int i = 0;
+    static uint64_t time = Params().GenesisBlock().nTime;
+
+    CScript pubKey;
+    pubKey << i++ << OP_TRUE;
+
+    auto ptemplate = BlockAssembler(Params()).CreateNewBlock(pubKey, false);
+    auto pblock = std::make_shared<CBlock>(ptemplate->block);
+    pblock->hashPrevBlock = prev_hash;
+    pblock->nTime = ++time;
+
+    CMutableTransaction txCoinbase(*pblock->vtx[0]);
+    txCoinbase.vout.resize(1);
+    txCoinbase.vin[0].scriptWitness.SetNull();
+    pblock->vtx[0] = MakeTransactionRef(std::move(txCoinbase));
+
+    return pblock;
+}
+
+std::shared_ptr<CBlock> FinalizeBlock(std::shared_ptr<CBlock> pblock)
+{
+    pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
+
+    while (!CheckProofOfWork(pblock->GetHash(), pblock->nBits, Params().GetConsensus())) {
+        ++(pblock->nNonce);
+    }
+
+    return pblock;
+}
+
+// construct a valid block
+const std::shared_ptr<const CBlock> GoodBlock(const uint256& prev_hash)
+{
+    return FinalizeBlock(Block(prev_hash));
+}
+
+// construct an invalid block (but with a valid header)
+const std::shared_ptr<const CBlock> BadBlock(const uint256& prev_hash)
+{
+    auto pblock = Block(prev_hash);
+
+    CMutableTransaction coinbase_spend;
+    coinbase_spend.vin.push_back(CTxIn(COutPoint(pblock->vtx[0]->GetHash(), 0), CScript(), 0));
+    coinbase_spend.vout.push_back(pblock->vtx[0]->vout[0]);
+
+    CTransactionRef tx = MakeTransactionRef(coinbase_spend);
+    pblock->vtx.push_back(tx);
+
+    auto ret = FinalizeBlock(pblock);
+    return ret;
+}
+
+void BuildChain(const uint256& root, int height, const unsigned int invalid_rate, const unsigned int branch_rate, const unsigned int max_size, std::vector<std::shared_ptr<const CBlock>>& blocks)
+{
+    if (height <= 0 || blocks.size() >= max_size) return;
+
+    bool gen_invalid = GetRand(100) < invalid_rate;
+    bool gen_fork = GetRand(100) < branch_rate;
+
+    const std::shared_ptr<const CBlock> pblock = gen_invalid ? BadBlock(root) : GoodBlock(root);
+    blocks.push_back(pblock);
+    if (!gen_invalid) {
+        BuildChain(pblock->GetHash(), height - 1, invalid_rate, branch_rate, max_size, blocks);
+    }
+
+    if (gen_fork) {
+        blocks.push_back(GoodBlock(root));
+        BuildChain(blocks.back()->GetHash(), height - 1, invalid_rate, branch_rate, max_size, blocks);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(processnewblock_signals_ordering)
+{
+    // build a large-ish chain that's likely to have some forks
+    std::vector<std::shared_ptr<const CBlock>> blocks;
+    while (blocks.size() < 50) {
+        blocks.clear();
+        BuildChain(Params().GenesisBlock().GetHash(), 100, 15, 10, 500, blocks);
+    }
+
+    bool ignored;
+    CValidationState state;
+    std::vector<CBlockHeader> headers;
+    std::transform(blocks.begin(), blocks.end(), std::back_inserter(headers), [](std::shared_ptr<const CBlock> b) { return b->GetBlockHeader(); });
+
+    // Process all the headers so we understand the toplogy of the chain
+    BOOST_CHECK(ProcessNewBlockHeaders(headers, state, Params()));
+
+    // Connect the genesis block and drain any outstanding events
+    ProcessNewBlock(Params(), std::make_shared<CBlock>(Params().GenesisBlock()), true, &ignored);
+    SyncWithValidationInterfaceQueue();
+
+    // subscribe to events (this subscriber will validate event ordering)
+    const CBlockIndex* initial_tip = nullptr;
+    {
+        LOCK(cs_main);
+        initial_tip = chainActive.Tip();
+    }
+    TestSubscriber sub(initial_tip->GetBlockHash());
+    RegisterValidationInterface(&sub);
+
+    // create a bunch of threads that repeatedly process a block generated above at random
+    // this will create parallelism and randomness inside validation - the ValidationInterface
+    // will subscribe to events generated during block validation and assert on ordering invariance
+    boost::thread_group threads;
+    for (int i = 0; i < 10; i++) {
+        threads.create_thread([&blocks]() {
+            bool ignored;
+            for (int i = 0; i < 1000; i++) {
+                auto block = blocks[GetRand(blocks.size() - 1)];
+                ProcessNewBlock(Params(), block, true, &ignored);
+            }
+
+            // to make sure that eventually we process the full chain - do it here
+            for (auto block : blocks) {
+                if (block->vtx.size() == 1) {
+                    bool processed = ProcessNewBlock(Params(), block, true, &ignored);
+                    assert(processed);
+                }
+            }
+        });
+    }
+
+    threads.join_all();
+    while (GetMainSignals().CallbacksPending() > 0) {
+        MilliSleep(100);
+    }
+
+    UnregisterValidationInterface(&sub);
+
+    BOOST_CHECK_EQUAL(sub.m_expected_tip, chainActive.Tip()->GetBlockHash());
+}
+
+BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/validation.cpp b/src/validation.cpp
index f981d2659a..2c5b5a1a31 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -144,6 +144,12 @@ private:
       */
     std::set<CBlockIndex*> g_failed_blocks;
 
+    /**
+     * the ChainState CriticalSection
+     * A lock that must be held when modifying this ChainState - held in ActivateBestChain()
+     */
+    CCriticalSection m_cs_chainstate;
+
 public:
     CChain chainActive;
     BlockMap mapBlockIndex;
@@ -570,6 +576,12 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
     if (fRequireStandard && !IsStandardTx(tx, reason, witnessEnabled))
         return state.DoS(0, false, REJECT_NONSTANDARD, reason);
 
+    // Do not work on transactions that are too small.
+    // A transaction with 1 segwit input and 1 P2WPHK output has non-witness size of 82 bytes.
+    // Transactions smaller than this are not relayed to reduce unnecessary malloc overhead.
+    if (::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) < MIN_STANDARD_TX_NONWITNESS_SIZE)
+        return state.DoS(0, false, REJECT_NONSTANDARD, "tx-size-small");
+
     // Only accept nLockTime-using transactions that can be mined in the next
     // block; we don't want our mempool filled up with transactions that can't
     // be mined yet.
@@ -2451,6 +2463,7 @@ void CChainState::PruneBlockIndexCandidates() {
 bool CChainState::ActivateBestChainStep(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexMostWork, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, ConnectTrace& connectTrace)
 {
     AssertLockHeld(cs_main);
+
     const CBlockIndex *pindexOldTip = chainActive.Tip();
     const CBlockIndex *pindexFork = chainActive.FindFork(pindexMostWork);
 
@@ -2562,6 +2575,12 @@ bool CChainState::ActivateBestChain(CValidationState &state, const CChainParams&
     // sanely for performance or correctness!
     AssertLockNotHeld(cs_main);
 
+    // ABC maintains a fair degree of expensive-to-calculate internal state
+    // because this function periodically releases cs_main so that it does not lock up other threads for too long
+    // during large connects - and to allow for e.g. the callback queue to drain
+    // we use m_cs_chainstate to enforce mutual exclusion so that only one caller may execute this function at a time
+    LOCK(m_cs_chainstate);
+
     CBlockIndex *pindexMostWork = nullptr;
     CBlockIndex *pindexNewTip = nullptr;
     int nStopAtHeight = gArgs.GetArg("-stopatheight", DEFAULT_STOPATHEIGHT);
@@ -2575,45 +2594,53 @@ bool CChainState::ActivateBestChain(CValidationState &state, const CChainParams&
             SyncWithValidationInterfaceQueue();
         }
 
-        const CBlockIndex *pindexFork;
-        bool fInitialDownload;
         {
             LOCK(cs_main);
-            ConnectTrace connectTrace(mempool); // Destructed before cs_main is unlocked
+            CBlockIndex* starting_tip = chainActive.Tip();
+            bool blocks_connected = false;
+            do {
+                // We absolutely may not unlock cs_main until we've made forward progress
+                // (with the exception of shutdown due to hardware issues, low disk space, etc).
+                ConnectTrace connectTrace(mempool); // Destructed before cs_main is unlocked
+
+                if (pindexMostWork == nullptr) {
+                    pindexMostWork = FindMostWorkChain();
+                }
 
-            CBlockIndex *pindexOldTip = chainActive.Tip();
-            if (pindexMostWork == nullptr) {
-                pindexMostWork = FindMostWorkChain();
-            }
+                // Whether we have anything to do at all.
+                if (pindexMostWork == nullptr || pindexMostWork == chainActive.Tip()) {
+                    break;
+                }
 
-            // Whether we have anything to do at all.
-            if (pindexMostWork == nullptr || pindexMostWork == chainActive.Tip())
-                return true;
+                bool fInvalidFound = false;
+                std::shared_ptr<const CBlock> nullBlockPtr;
+                if (!ActivateBestChainStep(state, chainparams, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : nullBlockPtr, fInvalidFound, connectTrace))
+                    return false;
+                blocks_connected = true;
 
-            bool fInvalidFound = false;
-            std::shared_ptr<const CBlock> nullBlockPtr;
-            if (!ActivateBestChainStep(state, chainparams, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : nullBlockPtr, fInvalidFound, connectTrace))
-                return false;
+                if (fInvalidFound) {
+                    // Wipe cache, we may need another branch now.
+                    pindexMostWork = nullptr;
+                }
+                pindexNewTip = chainActive.Tip();
 
-            if (fInvalidFound) {
-                // Wipe cache, we may need another branch now.
-                pindexMostWork = nullptr;
-            }
-            pindexNewTip = chainActive.Tip();
-            pindexFork = chainActive.FindFork(pindexOldTip);
-            fInitialDownload = IsInitialBlockDownload();
+                for (const PerBlockConnectTrace& trace : connectTrace.GetBlocksConnected()) {
+                    assert(trace.pblock && trace.pindex);
+                    GetMainSignals().BlockConnected(trace.pblock, trace.pindex, trace.conflictedTxs);
+                }
+            } while (!chainActive.Tip() || (starting_tip && CBlockIndexWorkComparator()(chainActive.Tip(), starting_tip)));
+            if (!blocks_connected) return true;
 
-            for (const PerBlockConnectTrace& trace : connectTrace.GetBlocksConnected()) {
-                assert(trace.pblock && trace.pindex);
-                GetMainSignals().BlockConnected(trace.pblock, trace.pindex, trace.conflictedTxs);
-            }
+            const CBlockIndex* pindexFork = chainActive.FindFork(starting_tip);
+            bool fInitialDownload = IsInitialBlockDownload();
 
             // Notify external listeners about the new tip.
             // Enqueue while holding cs_main to ensure that UpdatedBlockTip is called in the order in which blocks are connected
-            GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, fInitialDownload);
-
-            // Always notify the UI if a new block tip was connected
             if (pindexFork != pindexNewTip) {
+                // Notify ValidationInterface subscribers
+                GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, fInitialDownload);
+
+                // Always notify the UI if a new block tip was connected
                 uiInterface.NotifyBlockTip(fInitialDownload, pindexNewTip);
             }
         }
@@ -2637,6 +2664,7 @@ bool CChainState::ActivateBestChain(CValidationState &state, const CChainParams&
 
     return true;
 }
+
 bool ActivateBestChain(CValidationState &state, const CChainParams& chainparams, std::shared_ptr<const CBlock> pblock) {
     return g_chainstate.ActivateBestChain(state, chainparams, std::move(pblock));
 }
@@ -2764,6 +2792,7 @@ bool CChainState::ResetBlockFailureFlags(CBlockIndex *pindex) {
         if (pindex->nStatus & BLOCK_FAILED_MASK) {
             pindex->nStatus &= ~BLOCK_FAILED_MASK;
             setDirtyBlockIndex.insert(pindex);
+            g_failed_blocks.erase(pindex);
         }
         pindex = pindex->pprev;
     }
diff --git a/src/validationinterface.h b/src/validationinterface.h
index 56ea698a2e..8f71be14c2 100644
--- a/src/validationinterface.h
+++ b/src/validationinterface.h
@@ -56,7 +56,11 @@ void SyncWithValidationInterfaceQueue();
 class CValidationInterface {
 protected:
     /**
-     * Notifies listeners of updated block chain tip
+     * Notifies listeners when the block chain tip advances.
+     *
+     * When multiple blocks are connected at once, UpdatedBlockTip will be called on the final tip
+     * but may not be called on every intermediate tip. If the latter behavior is desired,
+     * subscribe to BlockConnected() instead.
      *
      * Called on a background thread.
      */
diff --git a/test/functional/feature_bip68_sequence.py b/test/functional/feature_bip68_sequence.py
index 94b13653b9..2196bf5bc0 100755
--- a/test/functional/feature_bip68_sequence.py
+++ b/test/functional/feature_bip68_sequence.py
@@ -80,7 +80,7 @@ class BIP68Test(BitcoinTestFramework):
         tx2.nVersion = 2
         sequence_value = sequence_value & 0x7fffffff
         tx2.vin = [CTxIn(COutPoint(tx1_id, 0), nSequence=sequence_value)]
-        tx2.vout = [CTxOut(int(value-self.relayfee*COIN), CScript([b'a']))]
+        tx2.vout = [CTxOut(int(value - self.relayfee * COIN), CScript([b'a' * 35]))]
         tx2.rehash()
 
         assert_raises_rpc_error(-26, NOT_FINAL_ERROR, self.nodes[0].sendrawtransaction, ToHex(tx2))
@@ -222,7 +222,7 @@ class BIP68Test(BitcoinTestFramework):
             tx = CTransaction()
             tx.nVersion = 2
             tx.vin = [CTxIn(COutPoint(orig_tx.sha256, 0), nSequence=sequence_value)]
-            tx.vout = [CTxOut(int(orig_tx.vout[0].nValue - relayfee*COIN), CScript([b'a']))]
+            tx.vout = [CTxOut(int(orig_tx.vout[0].nValue - relayfee * COIN), CScript([b'a' * 35]))]
             tx.rehash()
 
             if (orig_tx.hash in node.getrawmempool()):
@@ -350,7 +350,7 @@ class BIP68Test(BitcoinTestFramework):
         tx3 = CTransaction()
         tx3.nVersion = 2
         tx3.vin = [CTxIn(COutPoint(tx2.sha256, 0), nSequence=sequence_value)]
-        tx3.vout = [CTxOut(int(tx2.vout[0].nValue - self.relayfee*COIN), CScript([b'a']))]
+        tx3.vout = [CTxOut(int(tx2.vout[0].nValue - self.relayfee * COIN), CScript([b'a' * 35]))]
         tx3.rehash()
 
         assert_raises_rpc_error(-26, NOT_FINAL_ERROR, self.nodes[0].sendrawtransaction, ToHex(tx3))
diff --git a/test/functional/feature_block.py b/test/functional/feature_block.py
index fe9bbda14b..fc1255de86 100755
--- a/test/functional/feature_block.py
+++ b/test/functional/feature_block.py
@@ -80,7 +80,7 @@ class FullBlockTest(ComparisonTestFramework):
         block.vtx.extend(tx_list)
 
     # this is a little handier to use than the version in blocktools.py
-    def create_tx(self, spend_tx, n, value, script=CScript([OP_TRUE])):
+    def create_tx(self, spend_tx, n, value, script=CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE])):
         tx = create_transaction(spend_tx, n, b"", value, script)
         return tx
 
@@ -1288,6 +1288,5 @@ class FullBlockTest(ComparisonTestFramework):
             chain1_tip += 2
 
 
-
 if __name__ == '__main__':
     FullBlockTest().main()
diff --git a/test/functional/feature_rbf.py b/test/functional/feature_rbf.py
index 6b7ab0f43e..f0aa6de878 100755
--- a/test/functional/feature_rbf.py
+++ b/test/functional/feature_rbf.py
@@ -123,7 +123,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
         tx1a = CTransaction()
         tx1a.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1a.vout = [CTxOut(1*COIN, CScript([b'a']))]
+        tx1a.vout = [CTxOut(1 * COIN, CScript([b'a' * 35]))]
         tx1a_hex = txToHex(tx1a)
         tx1a_txid = self.nodes[0].sendrawtransaction(tx1a_hex, True)
 
@@ -132,7 +132,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Should fail because we haven't changed the fee
         tx1b = CTransaction()
         tx1b.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1b.vout = [CTxOut(1*COIN, CScript([b'b']))]
+        tx1b.vout = [CTxOut(1 * COIN, CScript([b'b' * 35]))]
         tx1b_hex = txToHex(tx1b)
 
         # This will raise an exception due to insufficient fee
@@ -143,7 +143,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Extra 0.1 BTC fee
         tx1b = CTransaction()
         tx1b.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1b.vout = [CTxOut(int(0.9*COIN), CScript([b'b']))]
+        tx1b.vout = [CTxOut(int(0.9 * COIN), CScript([b'b' * 35]))]
         tx1b_hex = txToHex(tx1b)
         # Replacement still disabled even with "enough fee"
         assert_raises_rpc_error(-26, "txn-mempool-conflict", self.nodes[1].sendrawtransaction, tx1b_hex, True)
@@ -175,7 +175,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
             remaining_value -= 1*COIN
             tx = CTransaction()
             tx.vin = [CTxIn(prevout, nSequence=0)]
-            tx.vout = [CTxOut(remaining_value, CScript([1]))]
+            tx.vout = [CTxOut(remaining_value, CScript([1, OP_DROP] * 15 + [1]))]
             tx_hex = txToHex(tx)
             txid = self.nodes[0].sendrawtransaction(tx_hex, True)
             chain_txids.append(txid)
@@ -185,7 +185,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # child fees - 40 BTC - so this attempt is rejected.
         dbl_tx = CTransaction()
         dbl_tx.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        dbl_tx.vout = [CTxOut(initial_nValue - 30*COIN, CScript([1]))]
+        dbl_tx.vout = [CTxOut(initial_nValue - 30 * COIN, CScript([1] * 35))]
         dbl_tx_hex = txToHex(dbl_tx)
 
         # This will raise an exception due to insufficient fee
@@ -194,7 +194,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Accepted with sufficient fee
         dbl_tx = CTransaction()
         dbl_tx.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        dbl_tx.vout = [CTxOut(1*COIN, CScript([1]))]
+        dbl_tx.vout = [CTxOut(1 * COIN, CScript([1] * 35))]
         dbl_tx_hex = txToHex(dbl_tx)
         self.nodes[0].sendrawtransaction(dbl_tx_hex, True)
 
@@ -247,7 +247,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Attempt double-spend, will fail because too little fee paid
         dbl_tx = CTransaction()
         dbl_tx.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        dbl_tx.vout = [CTxOut(initial_nValue - fee*n, CScript([1]))]
+        dbl_tx.vout = [CTxOut(initial_nValue - fee * n, CScript([1] * 35))]
         dbl_tx_hex = txToHex(dbl_tx)
         # This will raise an exception due to insufficient fee
         assert_raises_rpc_error(-26, "insufficient fee", self.nodes[0].sendrawtransaction, dbl_tx_hex, True)
@@ -255,7 +255,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # 1 BTC fee is enough
         dbl_tx = CTransaction()
         dbl_tx.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        dbl_tx.vout = [CTxOut(initial_nValue - fee*n - 1*COIN, CScript([1]))]
+        dbl_tx.vout = [CTxOut(initial_nValue - fee * n - 1 * COIN, CScript([1] * 35))]
         dbl_tx_hex = txToHex(dbl_tx)
         self.nodes[0].sendrawtransaction(dbl_tx_hex, True)
 
@@ -275,7 +275,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
             dbl_tx = CTransaction()
             dbl_tx.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-            dbl_tx.vout = [CTxOut(initial_nValue - 2*fee*n, CScript([1]))]
+            dbl_tx.vout = [CTxOut(initial_nValue - 2 * fee * n, CScript([1] * 35))]
             dbl_tx_hex = txToHex(dbl_tx)
             # This will raise an exception
             assert_raises_rpc_error(-26, "too many potential replacements", self.nodes[0].sendrawtransaction, dbl_tx_hex, True)
@@ -290,7 +290,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
         tx1a = CTransaction()
         tx1a.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1a.vout = [CTxOut(1*COIN, CScript([b'a']))]
+        tx1a.vout = [CTxOut(1 * COIN, CScript([b'a' * 35]))]
         tx1a_hex = txToHex(tx1a)
         self.nodes[0].sendrawtransaction(tx1a_hex, True)
 
@@ -311,7 +311,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
         tx1a = CTransaction()
         tx1a.vin = [CTxIn(utxo1, nSequence=0)]
-        tx1a.vout = [CTxOut(int(1.1*COIN), CScript([b'a']))]
+        tx1a.vout = [CTxOut(int(1.1 * COIN), CScript([b'a' * 35]))]
         tx1a_hex = txToHex(tx1a)
         tx1a_txid = self.nodes[0].sendrawtransaction(tx1a_hex, True)
 
@@ -330,7 +330,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Spend tx1a's output to test the indirect case.
         tx1b = CTransaction()
         tx1b.vin = [CTxIn(COutPoint(tx1a_txid, 0), nSequence=0)]
-        tx1b.vout = [CTxOut(1*COIN, CScript([b'a']))]
+        tx1b.vout = [CTxOut(1 * COIN, CScript([b'a' * 35]))]
         tx1b_hex = txToHex(tx1b)
         tx1b_txid = self.nodes[0].sendrawtransaction(tx1b_hex, True)
         tx1b_txid = int(tx1b_txid, 16)
@@ -351,7 +351,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
         tx1 = CTransaction()
         tx1.vin = [CTxIn(confirmed_utxo)]
-        tx1.vout = [CTxOut(1*COIN, CScript([b'a']))]
+        tx1.vout = [CTxOut(1 * COIN, CScript([b'a' * 35]))]
         tx1_hex = txToHex(tx1)
         self.nodes[0].sendrawtransaction(tx1_hex, True)
 
@@ -390,7 +390,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         for i in range(MAX_REPLACEMENT_LIMIT+1):
             tx_i = CTransaction()
             tx_i.vin = [CTxIn(COutPoint(txid, i), nSequence=0)]
-            tx_i.vout = [CTxOut(split_value-fee, CScript([b'a']))]
+            tx_i.vout = [CTxOut(split_value - fee, CScript([b'a' * 35]))]
             tx_i_hex = txToHex(tx_i)
             self.nodes[0].sendrawtransaction(tx_i_hex, True)
 
@@ -423,14 +423,14 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Create a non-opting in transaction
         tx1a = CTransaction()
         tx1a.vin = [CTxIn(tx0_outpoint, nSequence=0xffffffff)]
-        tx1a.vout = [CTxOut(1*COIN, CScript([b'a']))]
+        tx1a.vout = [CTxOut(1 * COIN, CScript([b'a' * 35]))]
         tx1a_hex = txToHex(tx1a)
         tx1a_txid = self.nodes[0].sendrawtransaction(tx1a_hex, True)
 
         # Shouldn't be able to double-spend
         tx1b = CTransaction()
         tx1b.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1b.vout = [CTxOut(int(0.9*COIN), CScript([b'b']))]
+        tx1b.vout = [CTxOut(int(0.9 * COIN), CScript([b'b' * 35]))]
         tx1b_hex = txToHex(tx1b)
 
         # This will raise an exception
@@ -441,14 +441,14 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Create a different non-opting in transaction
         tx2a = CTransaction()
         tx2a.vin = [CTxIn(tx1_outpoint, nSequence=0xfffffffe)]
-        tx2a.vout = [CTxOut(1*COIN, CScript([b'a']))]
+        tx2a.vout = [CTxOut(1 * COIN, CScript([b'a' * 35]))]
         tx2a_hex = txToHex(tx2a)
         tx2a_txid = self.nodes[0].sendrawtransaction(tx2a_hex, True)
 
         # Still shouldn't be able to double-spend
         tx2b = CTransaction()
         tx2b.vin = [CTxIn(tx1_outpoint, nSequence=0)]
-        tx2b.vout = [CTxOut(int(0.9*COIN), CScript([b'b']))]
+        tx2b.vout = [CTxOut(int(0.9 * COIN), CScript([b'b' * 35]))]
         tx2b_hex = txToHex(tx2b)
 
         # This will raise an exception
@@ -471,12 +471,12 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
         tx3b = CTransaction()
         tx3b.vin = [CTxIn(COutPoint(tx1a_txid, 0), nSequence=0)]
-        tx3b.vout = [CTxOut(int(0.5*COIN), CScript([b'e']))]
+        tx3b.vout = [CTxOut(int(0.5 * COIN), CScript([b'e' * 35]))]
         tx3b_hex = txToHex(tx3b)
 
         tx3c = CTransaction()
         tx3c.vin = [CTxIn(COutPoint(tx2a_txid, 0), nSequence=0)]
-        tx3c.vout = [CTxOut(int(0.5*COIN), CScript([b'f']))]
+        tx3c.vout = [CTxOut(int(0.5 * COIN), CScript([b'f' * 35]))]
         tx3c_hex = txToHex(tx3c)
 
         self.nodes[0].sendrawtransaction(tx3b_hex, True)
@@ -493,7 +493,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
         tx1a = CTransaction()
         tx1a.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1a.vout = [CTxOut(1*COIN, CScript([b'a']))]
+        tx1a.vout = [CTxOut(1 * COIN, CScript([b'a' * 35]))]
         tx1a_hex = txToHex(tx1a)
         tx1a_txid = self.nodes[0].sendrawtransaction(tx1a_hex, True)
 
@@ -519,14 +519,14 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
         tx2a = CTransaction()
         tx2a.vin = [CTxIn(tx1_outpoint, nSequence=0)]
-        tx2a.vout = [CTxOut(1*COIN, CScript([b'a']))]
+        tx2a.vout = [CTxOut(1 * COIN, CScript([b'a' * 35]))]
         tx2a_hex = txToHex(tx2a)
         self.nodes[0].sendrawtransaction(tx2a_hex, True)
 
         # Lower fee, but we'll prioritise it
         tx2b = CTransaction()
         tx2b.vin = [CTxIn(tx1_outpoint, nSequence=0)]
-        tx2b.vout = [CTxOut(int(1.01*COIN), CScript([b'a']))]
+        tx2b.vout = [CTxOut(int(1.01 * COIN), CScript([b'a' * 35]))]
         tx2b.rehash()
         tx2b_hex = txToHex(tx2b)
 
diff --git a/test/functional/feature_segwit.py b/test/functional/feature_segwit.py
index ba6373fa33..05d71305de 100755
--- a/test/functional/feature_segwit.py
+++ b/test/functional/feature_segwit.py
@@ -16,7 +16,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 from test_framework.mininode import sha256, CTransaction, CTxIn, COutPoint, CTxOut, COIN, ToHex, FromHex
 from test_framework.address import script_to_p2sh, key_to_p2pkh
-from test_framework.script import CScript, OP_HASH160, OP_CHECKSIG, OP_0, hash160, OP_EQUAL, OP_DUP, OP_EQUALVERIFY, OP_1, OP_2, OP_CHECKMULTISIG, OP_TRUE
+from test_framework.script import CScript, OP_HASH160, OP_CHECKSIG, OP_0, hash160, OP_EQUAL, OP_DUP, OP_EQUALVERIFY, OP_1, OP_2, OP_CHECKMULTISIG, OP_TRUE, OP_DROP
 from io import BytesIO
 
 NODE_0 = 0
@@ -218,7 +218,7 @@ class SegWitTest(BitcoinTestFramework):
         # Now create tx2, which will spend from txid1.
         tx = CTransaction()
         tx.vin.append(CTxIn(COutPoint(int(txid1, 16), 0), b''))
-        tx.vout.append(CTxOut(int(49.99*COIN), CScript([OP_TRUE])))
+        tx.vout.append(CTxOut(int(49.99 * COIN), CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE])))
         tx2_hex = self.nodes[0].signrawtransaction(ToHex(tx))['hex']
         txid2 = self.nodes[0].sendrawtransaction(tx2_hex)
         tx = FromHex(CTransaction(), tx2_hex)
@@ -227,7 +227,7 @@ class SegWitTest(BitcoinTestFramework):
         # Now create tx3, which will spend from txid2
         tx = CTransaction()
         tx.vin.append(CTxIn(COutPoint(int(txid2, 16), 0), b""))
-        tx.vout.append(CTxOut(int(49.95*COIN), CScript([OP_TRUE]))) # Huge fee
+        tx.vout.append(CTxOut(int(49.95 * COIN), CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE])))  # Huge fee
         tx.calc_sha256()
         txid3 = self.nodes[0].sendrawtransaction(ToHex(tx))
         assert(tx.wit.is_null())
diff --git a/test/functional/p2p_compactblocks.py b/test/functional/p2p_compactblocks.py
index d9f461a049..1a280587bd 100755
--- a/test/functional/p2p_compactblocks.py
+++ b/test/functional/p2p_compactblocks.py
@@ -12,7 +12,8 @@ from test_framework.mininode import *
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 from test_framework.blocktools import create_block, create_coinbase, add_witness_commitment
-from test_framework.script import CScript, OP_TRUE
+from test_framework.script import CScript, OP_TRUE, OP_DROP
+
 
 # TestNode: A peer we use to send messages to bitcoind, and store responses.
 class TestNode(P2PInterface):
@@ -423,7 +424,7 @@ class CompactBlocksTest(BitcoinTestFramework):
         for i in range(num_transactions):
             tx = CTransaction()
             tx.vin.append(CTxIn(COutPoint(utxo[0], utxo[1]), b''))
-            tx.vout.append(CTxOut(utxo[2] - 1000, CScript([OP_TRUE])))
+            tx.vout.append(CTxOut(utxo[2] - 1000, CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE])))
             tx.rehash()
             utxo = [tx.sha256, 0, tx.vout[0].nValue]
             block.vtx.append(tx)
diff --git a/test/functional/p2p_invalid_tx.py b/test/functional/p2p_invalid_tx.py
index 9c1100e070..0391fcdd18 100755
--- a/test/functional/p2p_invalid_tx.py
+++ b/test/functional/p2p_invalid_tx.py
@@ -64,7 +64,7 @@ class InvalidTxRequestTest(ComparisonTestFramework):
 
         # b'\x64' is OP_NOTIF
         # Transaction will be rejected with code 16 (REJECT_INVALID)
-        tx1 = create_transaction(self.block1.vtx[0], 0, b'\x64', 50 * COIN - 12000)
+        tx1 = create_transaction(self.block1.vtx[0], 0, b'\x64' * 35, 50 * COIN - 12000)
         yield TestInstance([[tx1, RejectResult(16, b'mandatory-script-verify-flag-failed')]])
 
         # TODO: test further transactions...
diff --git a/test/functional/p2p_segwit.py b/test/functional/p2p_segwit.py
index 20e4805df0..386e808310 100755
--- a/test/functional/p2p_segwit.py
+++ b/test/functional/p2p_segwit.py
@@ -168,7 +168,7 @@ class SegWitTest(BitcoinTestFramework):
         # Create a transaction that spends the coinbase
         tx = CTransaction()
         tx.vin.append(CTxIn(COutPoint(txid, 0), b""))
-        tx.vout.append(CTxOut(49*100000000, CScript([OP_TRUE])))
+        tx.vout.append(CTxOut(49 * 100000000, CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE])))
         tx.calc_sha256()
 
         # Check that serializing it with or without witness is the same
@@ -259,7 +259,7 @@ class SegWitTest(BitcoinTestFramework):
         # Now create a new anyone-can-spend utxo for the next test.
         tx4 = CTransaction()
         tx4.vin.append(CTxIn(COutPoint(tx3.sha256, 0), CScript([p2sh_program])))
-        tx4.vout.append(CTxOut(tx3.vout[0].nValue-1000, CScript([OP_TRUE])))
+        tx4.vout.append(CTxOut(tx3.vout[0].nValue - 1000, CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE])))
         tx4.rehash()
         test_transaction_acceptance(self.nodes[0].rpc, self.test_node, tx3, False, True)
         test_transaction_acceptance(self.nodes[0].rpc, self.test_node, tx4, False, True)
@@ -814,7 +814,7 @@ class SegWitTest(BitcoinTestFramework):
         assert(len(self.utxo))
         tx = CTransaction()
         tx.vin.append(CTxIn(COutPoint(self.utxo[0].sha256, self.utxo[0].n), b""))
-        tx.vout.append(CTxOut(self.utxo[0].nValue-1000, CScript([OP_TRUE])))
+        tx.vout.append(CTxOut(self.utxo[0].nValue - 1000, CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE])))
         tx.wit.vtxinwit.append(CTxInWitness())
         tx.wit.vtxinwit[0].scriptWitness.stack = [ b'a' ]
         tx.rehash()
@@ -866,7 +866,7 @@ class SegWitTest(BitcoinTestFramework):
         assert(len(self.utxo))
         tx = CTransaction()
         tx.vin.append(CTxIn(COutPoint(self.utxo[0].sha256, self.utxo[0].n), b""))
-        tx.vout.append(CTxOut(self.utxo[0].nValue-1000, CScript([OP_TRUE])))
+        tx.vout.append(CTxOut(self.utxo[0].nValue - 1000, CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE])))
         tx.wit.vtxinwit.append(CTxInWitness())
         tx.wit.vtxinwit[0].scriptWitness.stack = [ b'a' ]
         tx.rehash()
@@ -910,7 +910,7 @@ class SegWitTest(BitcoinTestFramework):
         test_transaction_acceptance(self.nodes[1].rpc, self.std_node, tx3, True, False, b'tx-size')
 
         # Remove witness stuffing, instead add extra witness push on stack
-        tx3.vout[0] = CTxOut(tx2.vout[0].nValue-1000, CScript([OP_TRUE]))
+        tx3.vout[0] = CTxOut(tx2.vout[0].nValue - 1000, CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE]))
         tx3.wit.vtxinwit[0].scriptWitness.stack = [CScript([CScriptNum(1)]), witness_program ]
         tx3.rehash()
 
@@ -1096,7 +1096,7 @@ class SegWitTest(BitcoinTestFramework):
             # P2PKH output; just send tx's first output back to an anyone-can-spend.
             sync_mempools([self.nodes[0], self.nodes[1]])
             tx3.vin = [CTxIn(COutPoint(tx.sha256, 0), b"")]
-            tx3.vout = [CTxOut(tx.vout[0].nValue-1000, CScript([OP_TRUE]))]
+            tx3.vout = [CTxOut(tx.vout[0].nValue - 1000, CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE]))]
             tx3.wit.vtxinwit.append(CTxInWitness())
             tx3.wit.vtxinwit[0].scriptWitness.stack = [witness_program]
             tx3.rehash()
@@ -1104,7 +1104,7 @@ class SegWitTest(BitcoinTestFramework):
         else:
             # tx and tx2 didn't go anywhere; just clean up the p2sh_tx output.
             tx3.vin = [CTxIn(COutPoint(p2sh_tx.sha256, 0), CScript([witness_program]))]
-            tx3.vout = [CTxOut(p2sh_tx.vout[0].nValue-1000, witness_program)]
+            tx3.vout = [CTxOut(p2sh_tx.vout[0].nValue - 1000, CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE]))]
             tx3.rehash()
             test_transaction_acceptance(self.nodes[0].rpc, self.test_node, tx3, with_witness=True, accepted=True)