fixup! txscript/engine: add execution StepCallback

txscript/engine.go

@@ -304,12 +304,6 @@ type StepInfo struct {
 	// OpcodeIndex is the index of the next opcode that will be executed.
 	OpcodeIndex int
 
-	// Witness is the witness of the current input.
-	//
-	// NOTE: this will be only be set before the witness program has been
-	// verified.
-	Witness [][]byte
-
 	// Stack is the Engine's current content on the stack:
 	Stack [][]byte
 
@@ -1070,7 +1064,6 @@ func (vm *Engine) Execute() (err error) {
 		stepInfo = &StepInfo{
 			ScriptIndex: vm.scriptIdx,
 			OpcodeIndex: vm.opcodeIdx,
-			Witness:     vm.tx.TxIn[vm.txIdx].Witness,
 			Stack:       vm.dstack.stk,
 			AltStack:    vm.astack.stk,
 		}
@@ -1121,18 +1114,9 @@ func (vm *Engine) Execute() (err error) {
 				opcodeIdx = stepInfo.OpcodeIndex + 1
 			}
 
-			witness := vm.tx.TxIn[vm.txIdx].Witness
-
-			// When the witness script (index 2) is being executed,
-			// the input witness is no longer relevant.
-			if scriptIdx > 1 {
-				witness = nil
-			}
-
 			stepInfo = &StepInfo{
 				ScriptIndex: scriptIdx,
 				OpcodeIndex: opcodeIdx,
-				Witness:     witness,
 				Stack:       vm.dstack.stk,
 				AltStack:    vm.astack.stk,
 			}