Merge #18612: script: Remove undocumented and unused operator+

ccccd51 script: Remove undocumented and unused operator+ (MarcoFalke)

Pull request description:

  This operator has no documented use case and is also unused outside of test code. The test code and all other (imaginary) code that might use this operator is written more clear and concise by the existing CScript push operators for opcodes and data.

  Removing the operator is also going to protect against accidentally reintroducing bugs like this bitcoin/bitcoin@6ff5f71#diff-8458adcedc17d046942185cb709ff5c3L1135 (last time it was used).

ACKs for top commit:
  laanwj:
    ACK ccccd51

Tree-SHA512: 43898ac77e4d9643d9f8ac6f8f65497a4f0bbb1fb5dcaecc839c3719aa36181ba77befb213e59a9f33a20a29e0173a0e9c4763b1930940b32c3d1598b3e39af9

Author: laanwj

src/script/script.h

@@ -419,28 +419,15 @@ class CScript : public CScriptBase
         READWRITEAS(CScriptBase, *this);
     }
 
-    CScript& operator+=(const CScript& b)
-    {
-        reserve(size() + b.size());
-        insert(end(), b.begin(), b.end());
-        return *this;
-    }
-
-    friend CScript operator+(const CScript& a, const CScript& b)
-    {
-        CScript ret = a;
-        ret += b;
-        return ret;
-    }
-
     explicit CScript(int64_t b) { operator<<(b); }
-
     explicit CScript(opcodetype b)     { operator<<(b); }
     explicit CScript(const CScriptNum& b) { operator<<(b); }
     // delete non-existent constructor to defend against future introduction
     // e.g. via prevector
     explicit CScript(const std::vector<unsigned char>& b) = delete;
 
+    /** Delete non-existent operator to defend against future introduction */
+    CScript& operator<<(const CScript& b) = delete;
 
     CScript& operator<<(int64_t b) { return push_int64(b); }
 
@@ -487,15 +474,6 @@ class CScript : public CScriptBase
         return *this;
     }
 
-    CScript& operator<<(const CScript& b)
-    {
-        // I'm not sure if this should push the script or concatenate scripts.
-        // If there's ever a use for pushing a script onto a script, delete this member fn
-        assert(!"Warning: Pushing a CScript onto a CScript with << is probably not intended, use + to concatenate!");
-        return *this;
-    }
-
-
     bool GetOp(const_iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>& vchRet) const
     {
         return GetScriptOp(pc, end(), opcodeRet, &vchRet);
@@ -506,7 +484,6 @@ class CScript : public CScriptBase
         return GetScriptOp(pc, end(), opcodeRet, nullptr);
     }
 
-
     /** Encode/decode small integers: */
     static int DecodeOP_N(opcodetype opcode)
     {

src/test/fuzz/script_ops.cpp

@@ -17,12 +17,16 @@ void test_one_input(const std::vector<uint8_t>& buffer)
     CScript script = ConsumeScript(fuzzed_data_provider);
     while (fuzzed_data_provider.remaining_bytes() > 0) {
         switch (fuzzed_data_provider.ConsumeIntegralInRange(0, 7)) {
-        case 0:
-            script += ConsumeScript(fuzzed_data_provider);
+        case 0: {
+            CScript s = ConsumeScript(fuzzed_data_provider);
+            script = std::move(s);
             break;
-        case 1:
-            script = script + ConsumeScript(fuzzed_data_provider);
+        }
+        case 1: {
+            const CScript& s = ConsumeScript(fuzzed_data_provider);
+            script = s;
             break;
+        }
         case 2:
             script << fuzzed_data_provider.ConsumeIntegral<int64_t>();
             break;

src/test/script_tests.cpp

@@ -217,7 +217,6 @@ struct KeyData
 
     KeyData()
     {
-
         key0.Set(vchKey0, vchKey0 + 32, false);
         key0C.Set(vchKey0, vchKey0 + 32, true);
         pubkey0 = key0.GetPubKey();
@@ -272,9 +271,9 @@ class TestBuilder
 
     void DoPush(const std::vector<unsigned char>& data)
     {
-         DoPush();
-         push = data;
-         havePush = true;
+        DoPush();
+        push = data;
+        havePush = true;
     }
 
 public:
@@ -306,10 +305,10 @@ class TestBuilder
         return *this;
     }
 
-    TestBuilder& Add(const CScript& _script)
+    TestBuilder& Opcode(const opcodetype& _op)
     {
         DoPush();
-        spendTx.vin[0].scriptSig += _script;
+        spendTx.vin[0].scriptSig << _op;
         return *this;
     }
 
@@ -326,8 +325,9 @@ class TestBuilder
         return *this;
     }
 
-    TestBuilder& Push(const CScript& _script) {
-         DoPush(std::vector<unsigned char>(_script.begin(), _script.end()));
+    TestBuilder& Push(const CScript& _script)
+    {
+        DoPush(std::vector<unsigned char>(_script.begin(), _script.end()));
         return *this;
     }
 
@@ -681,22 +681,22 @@ BOOST_AUTO_TEST_CASE(script_build)
 
     tests.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey1C) << OP_2 << OP_CHECKMULTISIG,
                                 "2-of-2 with two identical keys and sigs pushed using OP_DUP but no SIGPUSHONLY", 0
-                               ).Num(0).PushSig(keys.key1).Add(CScript() << OP_DUP));
+                               ).Num(0).PushSig(keys.key1).Opcode(OP_DUP));
     tests.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey1C) << OP_2 << OP_CHECKMULTISIG,
                                 "2-of-2 with two identical keys and sigs pushed using OP_DUP", SCRIPT_VERIFY_SIGPUSHONLY
-                               ).Num(0).PushSig(keys.key1).Add(CScript() << OP_DUP).ScriptError(SCRIPT_ERR_SIG_PUSHONLY));
+                               ).Num(0).PushSig(keys.key1).Opcode(OP_DUP).ScriptError(SCRIPT_ERR_SIG_PUSHONLY));
     tests.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey2C) << OP_CHECKSIG,
                                 "P2SH(P2PK) with non-push scriptSig but no P2SH or SIGPUSHONLY", 0, true
-                               ).PushSig(keys.key2).Add(CScript() << OP_NOP8).PushRedeem());
+                               ).PushSig(keys.key2).Opcode(OP_NOP8).PushRedeem());
     tests.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey2C) << OP_CHECKSIG,
                                 "P2PK with non-push scriptSig but with P2SH validation", 0
-                               ).PushSig(keys.key2).Add(CScript() << OP_NOP8));
+                               ).PushSig(keys.key2).Opcode(OP_NOP8));
     tests.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey2C) << OP_CHECKSIG,
                                 "P2SH(P2PK) with non-push scriptSig but no SIGPUSHONLY", SCRIPT_VERIFY_P2SH, true
-                               ).PushSig(keys.key2).Add(CScript() << OP_NOP8).PushRedeem().ScriptError(SCRIPT_ERR_SIG_PUSHONLY));
+                               ).PushSig(keys.key2).Opcode(OP_NOP8).PushRedeem().ScriptError(SCRIPT_ERR_SIG_PUSHONLY));
     tests.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey2C) << OP_CHECKSIG,
                                 "P2SH(P2PK) with non-push scriptSig but not P2SH", SCRIPT_VERIFY_SIGPUSHONLY, true
-                               ).PushSig(keys.key2).Add(CScript() << OP_NOP8).PushRedeem().ScriptError(SCRIPT_ERR_SIG_PUSHONLY));
+                               ).PushSig(keys.key2).Opcode(OP_NOP8).PushRedeem().ScriptError(SCRIPT_ERR_SIG_PUSHONLY));
     tests.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey1C) << OP_2 << OP_CHECKMULTISIG,
                                 "2-of-2 with two identical keys and sigs pushed", SCRIPT_VERIFY_SIGPUSHONLY
                                ).Num(0).PushSig(keys.key1).PushSig(keys.key1));
@@ -1470,24 +1470,6 @@ BOOST_AUTO_TEST_CASE(script_HasValidOps)
     BOOST_CHECK(!script.HasValidOps());
 }
 
-BOOST_AUTO_TEST_CASE(script_can_append_self)
-{
-    CScript s, d;
-
-    s = ScriptFromHex("00");
-    s += s;
-    d = ScriptFromHex("0000");
-    BOOST_CHECK(s == d);
-
-    // check doubling a script that's large enough to require reallocation
-    static const char hex[] = "04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5f";
-    s = CScript() << ParseHex(hex) << OP_CHECKSIG;
-    d = CScript() << ParseHex(hex) << OP_CHECKSIG << ParseHex(hex) << OP_CHECKSIG;
-    s += s;
-    BOOST_CHECK(s == d);
-}
-
-
 #if defined(HAVE_CONSENSUS_LIB)
 
 /* Test simple (successful) usage of bitcoinconsensus_verify_script */