Merge #14636: Avoid using numeric_limits for sequence numbers and lock times

535203075e Avoid using numeric_limits for sequence numbers and lock times (Russell Yanofsky)
bafb921507 Remove duplicated code (Hennadii Stepanov)
e4dc39b3bc 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 https://github.com/bitcoin/bitcoin/pull/10973#discussion_r213473620

  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.

Tree-SHA512: 3f5c6393c260551f65a0edfba55ef7eb3625232eec8d85b1457f26e144aa0b90c7ef5f44b2fd2f7d9be3c3bcb301030a9f5473c21b3bac566cc59b8c8780737c

1 files changed, 6 insertions, 0 deletions

diff --git a/src/script/script.h b/src/script/script.h
index 00065a24be..1d8ddba2f2 100644
--- a/src/script/script.h
+++ b/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)
 {