Check that the pc validation code works ok.

Add a testing only interface to set the pc and set it to a few invalid
settings to check that step and disasmPC all blow up correctly.

internal_test.go

@@ -42,3 +42,10 @@ func TstTypeOfScript(script []byte) TstScriptType {
 	}
 	return TstScriptType(typeOfScript(pops))
 }
+
+// TestSetPC allows the test modules to set the program counter to whatever they
+// want.
+func (s *Script) TstSetPC(script, off int) {
+	s.scriptidx = script
+	s.scriptoff = off
+}

script_test.go

@@ -1264,3 +1264,75 @@ func TestScriptTypes(t *testing.T) {
 		testScriptType(t, &scriptTypeTests[i])
 	}
 }
+
+// This test sets the pc to a deliberately bad result then confirms that Step()
+//  and Disasm fail correctly.
+func TestBadPC(t *testing.T) {
+	type pcTest struct {
+		script, off int
+	}
+	pcTests := []pcTest{
+		pcTest{
+			script:2,
+			off:0,
+		},
+		pcTest{
+			script: 0,
+			off: 2,
+		},
+	}
+	// tx with almost empty scripts.
+	tx := &btcwire.MsgTx{
+		Version: 1,
+		TxIn: []*btcwire.TxIn{
+			&btcwire.TxIn{
+				PreviousOutpoint: btcwire.OutPoint{
+					Hash: btcwire.ShaHash([32]byte{
+						0xc9, 0x97, 0xa5, 0xe5,
+						0x6e, 0x10, 0x41, 0x02,
+						0xfa, 0x20, 0x9c, 0x6a,
+						0x85, 0x2d, 0xd9, 0x06,
+						0x60, 0xa2, 0x0b, 0x2d,
+						0x9c, 0x35, 0x24, 0x23,
+						0xed, 0xce, 0x25, 0x85,
+						0x7f, 0xcd, 0x37, 0x04,
+					}),
+					Index: 0,
+				},
+				SignatureScript: []uint8{btcscript.OP_NOP},
+				Sequence: 4294967295,
+			},
+		},
+		TxOut: []*btcwire.TxOut{
+			&btcwire.TxOut{
+				Value: 1000000000,
+				PkScript: []byte{},
+			},
+		},
+		LockTime: 0,
+	}
+	pkScript := []byte{btcscript.OP_NOP}
+
+	for _, test := range pcTests {
+		engine, err :=  btcscript.NewScript(tx.TxIn[0].SignatureScript,
+			pkScript, 0, tx, 70001, false)
+		if err != nil {
+			t.Errorf("Failed to create script: %v", err)
+		}
+
+		// set to after all scripts
+		engine.TstSetPC(test.script, test.off)
+
+		_, err = engine.Step()
+		if err == nil {
+			t.Errorf("Step with invalid pc (%v) succeeds!", test)
+			continue
+		}
+
+		_, err = engine.DisasmPC()
+		if err == nil {
+			t.Errorf("DisasmPC with invalid pc (%v) succeeds!",
+				test)
+		}
+	}
+}

test_coverage.txt

@@ -2,54 +2,55 @@
 github.com/conformal/btcscript/stack.go		 asInt				 100.00% (18/18)
 github.com/conformal/btcscript/stack.go		 fromInt			 100.00% (14/14)
 github.com/conformal/btcscript/opcode.go	 opcodeWithin			 100.00% (13/13)
-github.com/conformal/btcscript/opcode.go	 parsedOpcode.bytes		 100.00% (12/12)
-github.com/conformal/btcscript/opcode.go	 parsedOpcode.print		 100.00% (12/12)
 github.com/conformal/btcscript/stack.go		 Stack.nipN			 100.00% (12/12)
+github.com/conformal/btcscript/opcode.go	 parsedOpcode.print		 100.00% (12/12)
+github.com/conformal/btcscript/opcode.go	 parsedOpcode.bytes		 100.00% (12/12)
 github.com/conformal/btcscript/opcode.go	 opcodeNotIf			 100.00% (11/11)
 github.com/conformal/btcscript/opcode.go	 opcodeIf			 100.00% (11/11)
-github.com/conformal/btcscript/opcode.go	 opcodeLessThan			 100.00% (10/10)
-github.com/conformal/btcscript/opcode.go	 opcodeBoolAnd			 100.00% (10/10)
-github.com/conformal/btcscript/opcode.go	 opcodeNumEqual			 100.00% (10/10)
-github.com/conformal/btcscript/opcode.go	 opcodeMin			 100.00% (10/10)
-github.com/conformal/btcscript/opcode.go	 opcodeMax			 100.00% (10/10)
-github.com/conformal/btcscript/opcode.go	 opcodeBoolOr			 100.00% (10/10)
-github.com/conformal/btcscript/opcode.go	 opcodeNumNotEqual		 100.00% (10/10)
 github.com/conformal/btcscript/opcode.go	 opcodeGreaterThan		 100.00% (10/10)
+github.com/conformal/btcscript/opcode.go	 opcodeLessThan			 100.00% (10/10)
+github.com/conformal/btcscript/opcode.go	 opcodeNumNotEqual		 100.00% (10/10)
+github.com/conformal/btcscript/opcode.go	 opcodeBoolOr			 100.00% (10/10)
+github.com/conformal/btcscript/opcode.go	 opcodeBoolAnd			 100.00% (10/10)
+github.com/conformal/btcscript/opcode.go	 opcodeMin			 100.00% (10/10)
+github.com/conformal/btcscript/opcode.go	 opcodeNumEqual			 100.00% (10/10)
 github.com/conformal/btcscript/stack.go		 Stack.Tuck			 100.00% (10/10)
-github.com/conformal/btcscript/opcode.go	 opcodeLessThanOrEqual		 100.00% (10/10)
+github.com/conformal/btcscript/opcode.go	 opcodeMax			 100.00% (10/10)
 github.com/conformal/btcscript/opcode.go	 opcodeGreaterThanOrEqual	 100.00% (10/10)
-github.com/conformal/btcscript/stack.go		 Stack.RotN			 100.00% (9/9)
+github.com/conformal/btcscript/opcode.go	 opcodeLessThanOrEqual		 100.00% (10/10)
-github.com/conformal/btcscript/script.go	 DisasmString			 100.00% (9/9)
 github.com/conformal/btcscript/stack.go		 Stack.OverN			 100.00% (9/9)
+github.com/conformal/btcscript/script.go	 DisasmString			 100.00% (9/9)
+github.com/conformal/btcscript/stack.go		 Stack.RotN			 100.00% (9/9)
 github.com/conformal/btcscript/stack.go		 Stack.SwapN			 100.00% (9/9)
-github.com/conformal/btcscript/opcode.go	 opcodeAdd			 100.00% (8/8)
-github.com/conformal/btcscript/stack.go		 Stack.DupN			 100.00% (8/8)
-github.com/conformal/btcscript/opcode.go	 opcodeSub			 100.00% (8/8)
 github.com/conformal/btcscript/opcode.go	 opcodeEqual			 100.00% (8/8)
+github.com/conformal/btcscript/opcode.go	 opcodeSub			 100.00% (8/8)
+github.com/conformal/btcscript/stack.go		 Stack.DupN			 100.00% (8/8)
+github.com/conformal/btcscript/opcode.go	 opcodeAdd			 100.00% (8/8)
 github.com/conformal/btcscript/opcode.go	 opcodePick			 100.00% (7/7)
-github.com/conformal/btcscript/opcode.go	 opcodeNot			 100.00% (7/7)
-github.com/conformal/btcscript/opcode.go	 opcode0NotEqual		 100.00% (7/7)
 github.com/conformal/btcscript/opcode.go	 opcodeRoll			 100.00% (7/7)
 github.com/conformal/btcscript/stack.go		 Stack.DropN			 100.00% (7/7)
+github.com/conformal/btcscript/opcode.go	 opcodeNot			 100.00% (7/7)
+github.com/conformal/btcscript/opcode.go	 opcode0NotEqual		 100.00% (7/7)
+github.com/conformal/btcscript/opcode.go	 parsedOpcode.conditional	 100.00% (6/6)
 github.com/conformal/btcscript/opcode.go	 opcodeIfDup			 100.00% (6/6)
 github.com/conformal/btcscript/opcode.go	 opcodeVerify			 100.00% (6/6)
-github.com/conformal/btcscript/opcode.go	 parsedOpcode.conditional	 100.00% (6/6)
 github.com/conformal/btcscript/opcode.go	 opcodeElse			 100.00% (6/6)
-github.com/conformal/btcscript/script.go	 removeOpcodeByData		 100.00% (5/5)
+github.com/conformal/btcscript/opcode.go	 opcodeHash160			 100.00% (5/5)
 github.com/conformal/btcscript/script.go	 removeOpcode			 100.00% (5/5)
-github.com/conformal/btcscript/opcode.go	 opcode1Add			 100.00% (5/5)
+github.com/conformal/btcscript/script.go	 removeOpcodeByData		 100.00% (5/5)
-github.com/conformal/btcscript/opcode.go	 opcodeSize			 100.00% (5/5)
+github.com/conformal/btcscript/stack.go		 Stack.PickN			 100.00% (5/5)
 github.com/conformal/btcscript/opcode.go	 opcodeAbs			 100.00% (5/5)
-github.com/conformal/btcscript/opcode.go	 opcodeRipemd160		 100.00% (5/5)
+github.com/conformal/btcscript/opcode.go	 opcodeHash256			 100.00% (5/5)
 github.com/conformal/btcscript/opcode.go	 opcodeToAltStack		 100.00% (5/5)
 github.com/conformal/btcscript/opcode.go	 opcodeFromAltStack		 100.00% (5/5)
+github.com/conformal/btcscript/opcode.go	 opcodeRipemd160		 100.00% (5/5)
 github.com/conformal/btcscript/opcode.go	 opcodeNegate			 100.00% (5/5)
 github.com/conformal/btcscript/opcode.go	 opcodeSha256			 100.00% (5/5)
-github.com/conformal/btcscript/opcode.go	 opcodeHash160			 100.00% (5/5)
+github.com/conformal/btcscript/opcode.go	 opcodeSize			 100.00% (5/5)
-github.com/conformal/btcscript/opcode.go	 opcodeHash256			 100.00% (5/5)
+github.com/conformal/btcscript/script.go	 Script.validPC			 100.00% (5/5)
-github.com/conformal/btcscript/stack.go		 Stack.PickN			 100.00% (5/5)
+github.com/conformal/btcscript/opcode.go	 opcode1Add			 100.00% (5/5)
-github.com/conformal/btcscript/stack.go		 Stack.RollN			 100.00% (5/5)
 github.com/conformal/btcscript/opcode.go	 opcode1Sub			 100.00% (5/5)
+github.com/conformal/btcscript/stack.go		 Stack.RollN			 100.00% (5/5)
 github.com/conformal/btcscript/stack.go		 Stack.PeekBool			 100.00% (4/4)
 github.com/conformal/btcscript/opcode.go	 opcodeEndif			 100.00% (4/4)
 github.com/conformal/btcscript/opcode.go	 opcodeEqualVerify		 100.00% (4/4)
@@ -61,50 +62,48 @@ github.com/conformal/btcscript/stack.go		 Stack.PeekByteArray		 100.00% (4/4)
 github.com/conformal/btcscript/stack.go		 Stack.PeekInt			 100.00% (4/4)
 github.com/conformal/btcscript/stack.go		 Stack.PopInt			 100.00% (4/4)
 github.com/conformal/btcscript/script.go	 unparseScript			 100.00% (4/4)
+github.com/conformal/btcscript/script.go	 Script.curPC			 100.00% (4/4)
+github.com/conformal/btcscript/script.go	 Script.DisasmPC		 100.00% (4/4)
 github.com/conformal/btcscript/script.go	 getStack			 100.00% (4/4)
-github.com/conformal/btcscript/script.go	 scriptUInt8			 100.00% (3/3)
 github.com/conformal/btcscript/address.go	 ScriptType.String		 100.00% (3/3)
 github.com/conformal/btcscript/stack.go		 fromBool			 100.00% (3/3)
 github.com/conformal/btcscript/script.go	 scriptUInt32			 100.00% (3/3)
+github.com/conformal/btcscript/script.go	 scriptUInt8			 100.00% (3/3)
 github.com/conformal/btcscript/script.go	 setStack			 100.00% (3/3)
 github.com/conformal/btcscript/script.go	 scriptUInt16			 100.00% (3/3)
 github.com/conformal/btcscript/stack.go		 Stack.NipN			 100.00% (2/2)
-github.com/conformal/btcscript/opcode.go	 opcodeDepth			 100.00% (2/2)
 github.com/conformal/btcscript/stack.go		 Stack.Depth			 100.00% (2/2)
 github.com/conformal/btcscript/opcode.go	 calcHash			 100.00% (2/2)
-github.com/conformal/btcscript/opcode.go	 opcodePushData			 100.00% (2/2)
-github.com/conformal/btcscript/opcode.go	 opcodeN			 100.00% (2/2)
 github.com/conformal/btcscript/opcode.go	 opcodeFalse			 100.00% (2/2)
+github.com/conformal/btcscript/opcode.go	 opcodeDepth			 100.00% (2/2)
 github.com/conformal/btcscript/opcode.go	 opcode1Negate			 100.00% (2/2)
+github.com/conformal/btcscript/opcode.go	 opcodeN			 100.00% (2/2)
 github.com/conformal/btcscript/opcode.go	 opcodeCodeSeparator		 100.00% (2/2)
-github.com/conformal/btcscript/opcode.go	 opcodeDisabled			 100.00% (1/1)
+github.com/conformal/btcscript/opcode.go	 opcodePushData			 100.00% (2/2)
-github.com/conformal/btcscript/opcode.go	 init				 100.00% (1/1)
-github.com/conformal/btcscript/script.go	 Script.SetStack		 100.00% (1/1)
-github.com/conformal/btcscript/log.go		 newLogClosure			 100.00% (1/1)
-github.com/conformal/btcscript/script.go	 Script.SetAltStack		 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcode2Rot			 100.00% (1/1)
-github.com/conformal/btcscript/opcode.go	 opcode2Over			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcode3Dup			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcode2Dup			 100.00% (1/1)
-github.com/conformal/btcscript/opcode.go	 opcode2Drop			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 calcHash160			 100.00% (1/1)
+github.com/conformal/btcscript/opcode.go	 opcode2Drop			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcodeReturn			 100.00% (1/1)
-github.com/conformal/btcscript/opcode.go	 opcode2Swap			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcodeNop			 100.00% (1/1)
+github.com/conformal/btcscript/stack.go		 Stack.PushByteArray		 100.00% (1/1)
 github.com/conformal/btcscript/stack.go		 Stack.PushInt			 100.00% (1/1)
 github.com/conformal/btcscript/stack.go		 Stack.PopByteArray		 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcodeInvalid			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcodeReserved			 100.00% (1/1)
-github.com/conformal/btcscript/script.go	 Script.GetStack		 100.00% (1/1)
+github.com/conformal/btcscript/opcode.go	 opcodeDisabled			 100.00% (1/1)
-github.com/conformal/btcscript/script.go	 Script.GetAltStack		 100.00% (1/1)
+github.com/conformal/btcscript/script.go	 isPubkey			 100.00% (1/1)
-github.com/conformal/btcscript/stack.go		 Stack.PushBool			 100.00% (1/1)
+github.com/conformal/btcscript/opcode.go	 init				 100.00% (1/1)
 github.com/conformal/btcscript/script.go	 Script.subScript		 100.00% (1/1)
 github.com/conformal/btcscript/log.go		 UseLogger			 100.00% (1/1)
-github.com/conformal/btcscript/log.go		 DisableLog			 100.00% (1/1)
+github.com/conformal/btcscript/script.go	 Script.SetStack		 100.00% (1/1)
-github.com/conformal/btcscript/script.go	 isPubkey			 100.00% (1/1)
 github.com/conformal/btcscript/script.go	 isPubkeyHash			 100.00% (1/1)
 github.com/conformal/btcscript/script.go	 isScriptHash			 100.00% (1/1)
+github.com/conformal/btcscript/log.go		 DisableLog			 100.00% (1/1)
+github.com/conformal/btcscript/script.go	 Script.GetAltStack		 100.00% (1/1)
 github.com/conformal/btcscript/log.go		 init				 100.00% (1/1)
+github.com/conformal/btcscript/script.go	 Script.SetAltStack		 100.00% (1/1)
 github.com/conformal/btcscript/script.go	 Script.disasm			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcodeTuck			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcodeSwap			 100.00% (1/1)
@@ -113,27 +112,28 @@ github.com/conformal/btcscript/opcode.go	 opcodeOver			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcodeNip			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcodeDup			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcodeDrop			 100.00% (1/1)
-github.com/conformal/btcscript/stack.go		 Stack.PushByteArray		 100.00% (1/1)
+github.com/conformal/btcscript/opcode.go	 opcode2Swap			 100.00% (1/1)
+github.com/conformal/btcscript/script.go	 Script.GetStack		 100.00% (1/1)
+github.com/conformal/btcscript/log.go		 newLogClosure			 100.00% (1/1)
+github.com/conformal/btcscript/opcode.go	 opcode2Over			 100.00% (1/1)
+github.com/conformal/btcscript/stack.go		 Stack.PushBool			 100.00% (1/1)
 github.com/conformal/btcscript/opcode.go	 opcodeCheckMultiSig		 96.43% (54/56)
 github.com/conformal/btcscript/opcode.go	 opcodeCheckSig			 96.15% (25/26)
 github.com/conformal/btcscript/script.go	 NewScript			 95.24% (20/21)
 github.com/conformal/btcscript/address.go	 ScriptToAddress		 94.92% (56/59)
 github.com/conformal/btcscript/script.go	 parseScript			 93.75% (30/32)
-github.com/conformal/btcscript/script.go	 Script.Step			 89.19% (33/37)
+github.com/conformal/btcscript/script.go	 Script.Step			 91.89% (34/37)
 github.com/conformal/btcscript/script.go	 typeOfScript			 83.33% (5/6)
-github.com/conformal/btcscript/opcode.go	 parsedOpcode.exec		 80.00% (4/5)
 github.com/conformal/btcscript/script.go	 Script.DisasmScript		 80.00% (4/5)
-github.com/conformal/btcscript/script.go	 Script.curPC			 75.00% (3/4)
+github.com/conformal/btcscript/opcode.go	 parsedOpcode.exec		 80.00% (4/5)
 github.com/conformal/btcscript/script.go	 isPushOnly			 75.00% (3/4)
 github.com/conformal/btcscript/opcode.go	 opcodeCheckSigVerify		 75.00% (3/4)
-github.com/conformal/btcscript/script.go	 Script.DisasmPC		 75.00% (3/4)
 github.com/conformal/btcscript/script.go	 Script.calcScriptHash		 71.43% (25/35)
 github.com/conformal/btcscript/script.go	 Script.CheckErrorCondition	 71.43% (10/14)
 github.com/conformal/btcscript/script.go	 isMultiSig			 61.54% (8/13)
-github.com/conformal/btcscript/script.go	 Script.validPC			 60.00% (3/5)
 github.com/conformal/btcscript/opcode.go	 opcodeSha1			 60.00% (3/5)
 github.com/conformal/btcscript/script.go	 Script.Execute			 44.44% (8/18)
 github.com/conformal/btcscript/log.go		 SetLogWriter			 0.00% (0/7)
 github.com/conformal/btcscript/log.go		 logClosure.String		 0.00% (0/1)
-github.com/conformal/btcscript			 --------------------------	 93.20% (836/897)
+github.com/conformal/btcscript			 --------------------------	 93.76% (841/897)