Merge bitcoin#14636: Avoid using numeric_limits for sequence numbers …

…and lock times (#4296)

Merges bitcoin#14636: Avoid using numeric_limits for sequence
numbers and lock times.

5352030 Avoid using numeric_limits for sequence numbers and lock
            times (Russell Yanofsky)
bafb921 Remove duplicated code (Hennadii Stepanov)
e4dc39b Replace platform dependent type with proper const
            (Hennadii Stepanov)

Pull request description:

  Switches to named constants, because numeric_limits calls can be
harder to read and less portable.

  Change was suggested by jamesob in
bitcoin#10973 (comment)

  There are no changes in behavior except on some platforms we don't
support (ILP64, IP16L32, I16LP32), where `SignalsOptInRBF` and
`MutateTxAddInput` functions would now work correctly.

src/dash-tx.cpp

@@ -237,7 +237,7 @@ static void MutateTxAddInput(CMutableTransaction& tx, const std::string& strInpu
         throw std::runtime_error("invalid TX input vout '" + strVout + "'");
 
     // extract the optional sequence number
-    uint32_t nSequenceIn=std::numeric_limits<unsigned int>::max();
+    uint32_t nSequenceIn = CTxIn::SEQUENCE_FINAL;
     if (vStrInputParts.size() > 2)
         nSequenceIn = std::stoul(vStrInputParts[2]);
 

src/rpc/rawtransaction.cpp

@@ -400,10 +400,9 @@ CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniVal
     UniValue outputs = outputs_is_obj ? outputs_in.get_obj() : outputs_in.get_array();
 
     CMutableTransaction rawTx;
-
     if (!locktime.isNull()) {
         int64_t nLockTime = locktime.get_int64();
-        if (nLockTime < 0 || nLockTime > std::numeric_limits<uint32_t>::max())
+        if (nLockTime < 0 || nLockTime > LOCKTIME_MAX)
             throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, locktime out of range");
         rawTx.nLockTime = nLockTime;
     }
@@ -421,13 +420,13 @@ CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniVal
         if (nOutput < 0)
             throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, vout must be positive");
 
-        uint32_t nSequence = (rawTx.nLockTime ? std::numeric_limits<uint32_t>::max() - 1 : std::numeric_limits<uint32_t>::max());
+        uint32_t nSequence = (rawTx.nLockTime ? CTxIn::SEQUENCE_FINAL - 1 : CTxIn::SEQUENCE_FINAL);
 
         // set the sequence number if passed in the parameters object
         const UniValue& sequenceObj = find_value(o, "sequence");
         if (sequenceObj.isNum()) {
             int64_t seqNr64 = sequenceObj.get_int64();
-            if (seqNr64 < 0 || seqNr64 > std::numeric_limits<uint32_t>::max())
+            if (seqNr64 < 0 || seqNr64 > CTxIn::SEQUENCE_FINAL)
                 throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, sequence number is out of range");
             else
                 nSequence = (uint32_t)seqNr64;

src/script/script.h

@@ -38,6 +38,12 @@ static const int MAX_STACK_SIZE = 1000;
 // otherwise as UNIX timestamp.
 static const unsigned int LOCKTIME_THRESHOLD = 500000000; // Tue Nov  5 00:53:20 1985 UTC
 
+// Maximum nLockTime. Since a lock time indicates the last invalid timestamp, a
+// transaction with this lock time will never be valid unless lock time
+// checking is disabled (by setting all input sequence numbers to
+// SEQUENCE_FINAL).
+static const uint32_t LOCKTIME_MAX = 0xFFFFFFFFU;
+
 template <typename T>
 std::vector<unsigned char> ToByteVector(const T& in)
 {

src/test/skiplist_tests.cpp

@@ -170,7 +170,6 @@ BOOST_AUTO_TEST_CASE(findearliestatleast_edge_test)
     BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(-1)->nHeight, 0);
 
     BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(std::numeric_limits<int64_t>::min())->nHeight, 0);
-    BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(std::numeric_limits<unsigned int>::min())->nHeight, 0);
     BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(-int64_t(std::numeric_limits<unsigned int>::max()) - 1)->nHeight, 0);
     BOOST_CHECK(!chain.FindEarliestAtLeast(std::numeric_limits<int64_t>::max()));
     BOOST_CHECK(!chain.FindEarliestAtLeast(std::numeric_limits<unsigned int>::max()));