core: allow to overload contract methods

Multiple methods with different parameter count can co-exist.

cli/wallet/wallet.go

@@ -419,7 +419,7 @@ func importDeployed(ctx *cli.Context) error {
 	if err != nil {
 		return cli.NewExitError(fmt.Errorf("can't fetch contract info: %w", err), 1)
 	}
-	md := cs.Manifest.ABI.GetMethod(manifest.MethodVerify)
+	md := cs.Manifest.ABI.GetMethod(manifest.MethodVerify, -1)
 	if md == nil {
 		return cli.NewExitError("contract has no `verify` method", 1)
 	}

pkg/core/blockchain.go

@@ -1667,11 +1667,11 @@ func (bc *Blockchain) initVerificationVM(ic *interop.Context, hash util.Uint160,
 		if err != nil {
 			return ErrUnknownVerificationContract
 		}
-		md := cs.Manifest.ABI.GetMethod(manifest.MethodVerify)
+		md := cs.Manifest.ABI.GetMethod(manifest.MethodVerify, -1)
 		if md == nil {
 			return ErrInvalidVerificationContract
 		}
-		initMD := cs.Manifest.ABI.GetMethod(manifest.MethodInit)
+		initMD := cs.Manifest.ABI.GetMethod(manifest.MethodInit, 0)
 		v.LoadScriptWithHash(cs.NEF.Script, hash, callflag.ReadStates)
 		v.Context().NEF = &cs.NEF
 		v.Jump(v.Context(), md.Offset)

pkg/core/interop/contract/call.go

@@ -55,7 +55,7 @@ func Call(ic *interop.Context) error {
 	if strings.HasPrefix(method, "_") {
 		return errors.New("invalid method name (starts with '_')")
 	}
-	md := cs.Manifest.ABI.GetMethod(method)
+	md := cs.Manifest.ABI.GetMethod(method, len(args))
 	if md == nil {
 		return errors.New("method not found")
 	}
@@ -68,7 +68,7 @@ func Call(ic *interop.Context) error {
 
 func callInternal(ic *interop.Context, cs *state.Contract, name string, f callflag.CallFlag,
 	hasReturn bool, args []stackitem.Item) error {
-	md := cs.Manifest.ABI.GetMethod(name)
+	md := cs.Manifest.ABI.GetMethod(name, len(args))
 	if md.Safe {
 		f &^= callflag.WriteStates
 	} else if ctx := ic.VM.Context(); ctx != nil && ctx.IsDeployed() {
@@ -85,7 +85,7 @@ func callInternal(ic *interop.Context, cs *state.Contract, name string, f callfl
 // callExFromNative calls a contract with flags using provided calling hash.
 func callExFromNative(ic *interop.Context, caller util.Uint160, cs *state.Contract,
 	name string, args []stackitem.Item, f callflag.CallFlag, hasReturn bool) error {
-	md := cs.Manifest.ABI.GetMethod(name)
+	md := cs.Manifest.ABI.GetMethod(name, len(args))
 	if md == nil {
 		return fmt.Errorf("method '%s' not found", name)
 	}
@@ -119,7 +119,7 @@ func callExFromNative(ic *interop.Context, caller util.Uint160, cs *state.Contra
 		ic.VM.Context().RetCount = 0
 	}
 
-	md = cs.Manifest.ABI.GetMethod(manifest.MethodInit)
+	md = cs.Manifest.ABI.GetMethod(manifest.MethodInit, 0)
 	if md != nil {
 		ic.VM.Call(ic.VM.Context(), md.Offset)
 	}

pkg/core/interop_system_test.go

@@ -461,6 +461,8 @@ func getTestContractState(bc *Blockchain) (*state.Contract, *state.Contract) {
 	emit.Opcodes(w.BinWriter, opcode.ABORT)
 	addOff := w.Len()
 	emit.Opcodes(w.BinWriter, opcode.ADD, opcode.RET)
+	addMultiOff := w.Len()
+	emit.Opcodes(w.BinWriter, opcode.ADD, opcode.ADD, opcode.RET)
 	ret7Off := w.Len()
 	emit.Opcodes(w.BinWriter, opcode.PUSH7, opcode.RET)
 	dropOff := w.Len()
@@ -533,6 +535,16 @@ func getTestContractState(bc *Blockchain) (*state.Contract, *state.Contract) {
 			},
 			ReturnType: smartcontract.IntegerType,
 		},
+		{
+			Name:   "add",
+			Offset: addMultiOff,
+			Parameters: []manifest.Parameter{
+				manifest.NewParameter("addend1", smartcontract.IntegerType),
+				manifest.NewParameter("addend2", smartcontract.IntegerType),
+				manifest.NewParameter("addend3", smartcontract.IntegerType),
+			},
+			ReturnType: smartcontract.IntegerType,
+		},
 		{
 			Name:       "ret7",
 			Offset:     ret7Off,
@@ -731,6 +743,7 @@ func TestContractCall(t *testing.T) {
 
 	addArgs := stackitem.NewArray([]stackitem.Item{stackitem.Make(1), stackitem.Make(2)})
 	t.Run("Good", func(t *testing.T) {
+		t.Run("2 arguments", func(t *testing.T) {
 			loadScript(ic, currScript, 42)
 			ic.VM.Estack().PushVal(addArgs)
 			ic.VM.Estack().PushVal(callflag.All)
@@ -742,6 +755,20 @@ func TestContractCall(t *testing.T) {
 			require.Equal(t, big.NewInt(3), ic.VM.Estack().Pop().Value())
 			require.Equal(t, big.NewInt(42), ic.VM.Estack().Pop().Value())
 		})
+		t.Run("3 arguments", func(t *testing.T) {
+			loadScript(ic, currScript, 42)
+			ic.VM.Estack().PushVal(stackitem.NewArray(
+				append(addArgs.Value().([]stackitem.Item), stackitem.Make(3))))
+			ic.VM.Estack().PushVal(callflag.All)
+			ic.VM.Estack().PushVal("add")
+			ic.VM.Estack().PushVal(h.BytesBE())
+			require.NoError(t, contract.Call(ic))
+			require.NoError(t, ic.VM.Run())
+			require.Equal(t, 2, ic.VM.Estack().Len())
+			require.Equal(t, big.NewInt(6), ic.VM.Estack().Pop().Value())
+			require.Equal(t, big.NewInt(42), ic.VM.Estack().Pop().Value())
+		})
+	})
 
 	t.Run("CallExInvalidFlag", func(t *testing.T) {
 		loadScript(ic, currScript, 42)
@@ -778,6 +805,10 @@ func TestContractCall(t *testing.T) {
 		t.Run("Arguments", runInvalid(1, "add", h.BytesBE()))
 		t.Run("NotEnoughArguments", runInvalid(
 			stackitem.NewArray([]stackitem.Item{stackitem.Make(1)}), "add", h.BytesBE()))
+		t.Run("TooMuchArguments", runInvalid(
+			stackitem.NewArray([]stackitem.Item{
+				stackitem.Make(1), stackitem.Make(2), stackitem.Make(3), stackitem.Make(4)}),
+			"add", h.BytesBE()))
 	})
 
 	t.Run("ReturnValues", func(t *testing.T) {

pkg/core/native/management.go

@@ -379,7 +379,7 @@ func (m *Management) setMinimumDeploymentFee(ic *interop.Context, args []stackit
 }
 
 func (m *Management) callDeploy(ic *interop.Context, cs *state.Contract, isUpdate bool) {
-	md := cs.Manifest.ABI.GetMethod(manifest.MethodDeploy)
+	md := cs.Manifest.ABI.GetMethod(manifest.MethodDeploy, 1)
 	if md != nil {
 		err := contract.CallFromNative(ic, m.Hash, cs, manifest.MethodDeploy,
 			[]stackitem.Item{stackitem.NewBool(isUpdate)}, false)

pkg/core/native_management_test.go

@@ -227,9 +227,8 @@ func TestContractDeploy(t *testing.T) {
 				Offset: 0,
 				Parameters: []manifest.Parameter{
 					manifest.NewParameter("isUpdate", smartcontract.BoolType),
-					manifest.NewParameter("param", smartcontract.IntegerType),
 				},
-				ReturnType: smartcontract.VoidType,
+				ReturnType: smartcontract.ArrayType,
 			},
 		}
 		nefD, err := nef.NewFile(deployScript)

pkg/smartcontract/manifest/manifest.go

@@ -76,9 +76,9 @@ func DefaultManifest(name string) *Manifest {
 }
 
 // GetMethod returns methods with the specified name.
-func (a *ABI) GetMethod(name string) *Method {
+func (a *ABI) GetMethod(name string, paramCount int) *Method {
 	for i := range a.Methods {
-		if a.Methods[i].Name == name {
+		if a.Methods[i].Name == name && (paramCount == -1 || len(a.Methods[i].Parameters) == paramCount) {
 			return &a.Methods[i]
 		}
 	}

pkg/smartcontract/manifest/standard/comply.go

@@ -40,15 +40,12 @@ func Check(m *manifest.Manifest, standards ...string) error {
 func Comply(m, st *manifest.Manifest) error {
 	for _, stm := range st.ABI.Methods {
 		name := stm.Name
-		md := m.ABI.GetMethod(name)
+		md := m.ABI.GetMethod(name, len(stm.Parameters))
 		if md == nil {
-			return fmt.Errorf("%w: '%s'", ErrMethodMissing, name)
+			return fmt.Errorf("%w: '%s' with %d parameters", ErrMethodMissing, name, len(stm.Parameters))
 		} else if stm.ReturnType != md.ReturnType {
 			return fmt.Errorf("%w: '%s' (expected %s, got %s)", ErrInvalidReturnType,
 				name, stm.ReturnType, md.ReturnType)
-		} else if len(stm.Parameters) != len(md.Parameters) {
-			return fmt.Errorf("%w: '%s' (expected %d, got %d)", ErrInvalidParameterCount,
-				name, len(stm.Parameters), len(md.Parameters))
 		}
 		for i := range stm.Parameters {
 			if stm.Parameters[i].Type != md.Parameters[i].Type {

pkg/smartcontract/manifest/standard/comply_test.go

@@ -37,14 +37,14 @@ func fooMethodBarEvent() *manifest.Manifest {
 
 func TestComplyMissingMethod(t *testing.T) {
 	m := fooMethodBarEvent()
-	m.ABI.GetMethod("foo").Name = "notafoo"
+	m.ABI.GetMethod("foo", -1).Name = "notafoo"
 	err := Comply(m, fooMethodBarEvent())
 	require.True(t, errors.Is(err, ErrMethodMissing))
 }
 
 func TestComplyInvalidReturnType(t *testing.T) {
 	m := fooMethodBarEvent()
-	m.ABI.GetMethod("foo").ReturnType = smartcontract.VoidType
+	m.ABI.GetMethod("foo", -1).ReturnType = smartcontract.VoidType
 	err := Comply(m, fooMethodBarEvent())
 	require.True(t, errors.Is(err, ErrInvalidReturnType))
 }
@@ -52,10 +52,10 @@ func TestComplyInvalidReturnType(t *testing.T) {
 func TestComplyMethodParameterCount(t *testing.T) {
 	t.Run("Method", func(t *testing.T) {
 		m := fooMethodBarEvent()
-		f := m.ABI.GetMethod("foo")
+		f := m.ABI.GetMethod("foo", -1)
 		f.Parameters = append(f.Parameters, manifest.Parameter{Type: smartcontract.BoolType})
 		err := Comply(m, fooMethodBarEvent())
-		require.True(t, errors.Is(err, ErrInvalidParameterCount))
+		require.True(t, errors.Is(err, ErrMethodMissing))
 	})
 	t.Run("Event", func(t *testing.T) {
 		m := fooMethodBarEvent()
@@ -69,7 +69,7 @@ func TestComplyMethodParameterCount(t *testing.T) {
 func TestComplyParameterType(t *testing.T) {
 	t.Run("Method", func(t *testing.T) {
 		m := fooMethodBarEvent()
-		m.ABI.GetMethod("foo").Parameters[0].Type = smartcontract.InteropInterfaceType
+		m.ABI.GetMethod("foo", -1).Parameters[0].Type = smartcontract.InteropInterfaceType
 		err := Comply(m, fooMethodBarEvent())
 		require.True(t, errors.Is(err, ErrInvalidParameterType))
 	})
@@ -90,7 +90,7 @@ func TestMissingEvent(t *testing.T) {
 
 func TestSafeFlag(t *testing.T) {
 	m := fooMethodBarEvent()
-	m.ABI.GetMethod("foo").Safe = false
+	m.ABI.GetMethod("foo", -1).Safe = false
 	err := Comply(m, fooMethodBarEvent())
 	require.True(t, errors.Is(err, ErrSafeMethodMismatch))
 }

pkg/vm/cli/cli.go

@@ -389,25 +389,25 @@ func handleRun(c *ishell.Context) {
 			runCurrent = c.Args[0] != "_"
 		)
 
+		params, err = parseArgs(c.Args[1:])
+		if err != nil {
+			c.Err(err)
+			return
+		}
 		if runCurrent {
-			md := m.ABI.GetMethod(c.Args[0])
+			md := m.ABI.GetMethod(c.Args[0], len(params))
 			if md == nil {
 				c.Err(fmt.Errorf("%w: method not found", ErrInvalidParameter))
 				return
 			}
 			offset = md.Offset
 		}
-		params, err = parseArgs(c.Args[1:])
-		if err != nil {
-			c.Err(err)
-			return
-		}
 		for i := len(params) - 1; i >= 0; i-- {
 			v.Estack().PushVal(params[i])
 		}
 		if runCurrent {
 			v.Jump(v.Context(), offset)
-			if initMD := m.ABI.GetMethod(manifest.MethodInit); initMD != nil {
+			if initMD := m.ABI.GetMethod(manifest.MethodInit, 0); initMD != nil {
 				v.Call(v.Context(), initMD.Offset)
 			}
 		}