Add returnVal any param validation to chainReader GetLatestValue

pkg/loop/internal/chain_reader.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/smartcontractkit/chainlink-relay/pkg/loop/internal/pb"
 	"github.com/smartcontractkit/chainlink-relay/pkg/types"
+	"github.com/smartcontractkit/chainlink-relay/pkg/utils"
 )
 
 var _ types.ChainReader = (*chainReaderClient)(nil)
@@ -15,7 +16,11 @@ type chainReaderClient struct {
 	grpc pb.ChainReaderClient
 }
 
-func (c *chainReaderClient) GetLatestValue(ctx context.Context, bc types.BoundContract, method string, params, retVal any) error {
+func (c *chainReaderClient) GetLatestValue(ctx context.Context, bc types.BoundContract, method string, params, returnVal any) error {
+	if err := utils.ValidateStructPtr(returnVal); err != nil {
+		return err
+	}
+
 	boundContract := pb.BoundContract{Name: bc.Name, Address: bc.Address, Pending: bc.Pending}
 	jsonParams, err := json.Marshal(params)
 	if err != nil {
@@ -26,7 +31,7 @@ func (c *chainReaderClient) GetLatestValue(ctx context.Context, bc types.BoundCo
 	if err != nil {
 		return err
 	}
-	return json.Unmarshal(reply.RetVal, &retVal)
+	return json.Unmarshal(reply.RetVal, &returnVal)
 }
 
 var _ pb.ChainReaderServer = (*chainReaderServer)(nil)

pkg/loop/internal/test/config.go

@@ -12,6 +12,7 @@ import (
 	"github.com/stretchr/testify/assert"
 
 	"github.com/smartcontractkit/chainlink-relay/pkg/types"
+	"github.com/smartcontractkit/chainlink-relay/pkg/utils"
 )
 
 type staticConfigProvider struct{}
@@ -93,6 +94,10 @@ func (s staticContractTransmitter) FromAccount() (libocr.Account, error) {
 type staticChainReader struct{}
 
 func (c staticChainReader) GetLatestValue(ctx context.Context, bc types.BoundContract, method string, params, returnVal any) error {
+	if err := utils.ValidateStructPtr(returnVal); err != nil {
+		return err
+	}
+
 	if !assert.ObjectsAreEqual(bc, boundContract) {
 		return fmt.Errorf("expected report context %v but got %v", boundContract, bc)
 	}

pkg/utils/utils.go

@@ -2,8 +2,10 @@ package utils
 
 import (
 	"context"
+	"fmt"
 	"math"
 	mrand "math/rand"
+	"reflect"
 	"time"
 )
 
@@ -38,6 +40,21 @@ func ContextFromChan(chStop <-chan struct{}) (context.Context, context.CancelFun
 	return ctx, cancel
 }
 
+// ValidateStructPtr checks if the input value is a pointer to a non-nil struct.
+func ValidateStructPtr(val any) error {
+	rv := reflect.ValueOf(val)
+	if rv.Kind() != reflect.Ptr || rv.IsNil() {
+		return fmt.Errorf("value of type %T is not a non-nil struct pointer", val)
+	}
+
+	rv = rv.Elem()
+	if !rv.IsValid() || rv.Kind() != reflect.Struct {
+		return fmt.Errorf("dereferenced value of type %T is not a valid struct", val)
+	}
+
+	return nil
+}
+
 // ContextWithDeadlineFn returns a copy of the parent context with the deadline modified by deadlineFn.
 // deadlineFn will only be called if the parent has a deadline.
 // The new deadline must be sooner than the old to have an effect.

pkg/utils/utils_test.go

@@ -0,0 +1,61 @@
+package utils_test
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/smartcontractkit/chainlink-relay/pkg/utils"
+)
+
+type ExampleStruct struct {
+	Name string
+}
+
+func TestValidateStructPtr(t *testing.T) {
+	testNum := 42
+	testCases := []struct {
+		name   string
+		input  interface{}
+		expect error
+	}{
+		{
+			name:   "struct pointer",
+			input:  &ExampleStruct{"Bob"},
+			expect: nil,
+		},
+		{
+			name:   "struct",
+			input:  ExampleStruct{"Alice"},
+			expect: errors.New("value of type utils_test.ExampleStruct is not a non-nil struct pointer"),
+		},
+		{
+			name:   "nil struct pointer",
+			input:  (*ExampleStruct)(nil),
+			expect: errors.New("value of type *utils_test.ExampleStruct is not a non-nil struct pointer"),
+		},
+		{
+			name:   "nil",
+			input:  nil,
+			expect: errors.New("value of type <nil> is not a non-nil struct pointer"),
+		},
+		{
+			name:   "non struct pointer",
+			input:  &testNum,
+			expect: errors.New("dereferenced value of type *int is not a valid struct"),
+		},
+		{
+			name:   "non struct type",
+			input:  testNum,
+			expect: errors.New("value of type int is not a non-nil struct pointer"),
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := utils.ValidateStructPtr(tc.input)
+			assert.Equal(t, tc.expect, result)
+		})
+	}
+}