Improve Go query error handling and add non-panicking Get APIs

bindings.go

@@ -99,7 +99,7 @@ func packItem(ns *reindexerNamespace, item any, json []byte, ser *cjson.Serializ
 		}
 		if t != ns.rtype {
 			if ns.rtype.Name() != t.Name() || ns.rtype.PkgPath() != t.PkgPath() {
-				panic(ErrWrongType)
+				return 0, 0, false, ErrWrongType
 			}
 		}
 

cjson/serializer.go

@@ -2,6 +2,7 @@ package cjson
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"math"
 	"reflect"
@@ -15,6 +16,7 @@ var isLittleEndian = func() bool {
 	var v uint16 = 0x0102
 	return *(*byte)(unsafe.Pointer(&v)) == 0x02
 }()
+var errInvalidReflectionValue = errors.New("rq: invalid reflection value")
 
 type Serializer struct {
 	buf  []byte
@@ -181,10 +183,12 @@ func (s *Serializer) PutValue(v reflect.Value) error {
 		s.PutVarCUInt(valueTuple)
 		s.PutVarCUInt(v.Len())
 		for i := 0; i < v.Len(); i++ {
-			s.PutValue(v.Index(i))
+			if err := s.PutValue(v.Index(i)); err != nil {
+				return err
+			}
 		}
 	default:
-		panic(fmt.Errorf("rq: Invalid reflection type %s", v.Kind().String()))
+		return errInvalidReflectionValue
 	}
 	return nil
 }

expression.go

@@ -39,12 +39,12 @@ type SubQuery struct {
 	SubQuery *Query
 }
 
-// FlatArrayLen is the flat_array_len(field) expression; implements IFunction and IExpression.
+// FlatArrayLen is the flat_array_len(field) expression.
 type FlatArrayLen struct {
 	Field string
 }
 
-// Now is the now(time_unit) expression; implements IFunction and IExpression.
+// Now is the now(time_unit) expression.
 type Now struct {
 	TimeUnit TimeUnit
 }
@@ -87,48 +87,6 @@ func (s SubQuery) Serialize(ser *cjson.Serializer) {
 	ser.PutVBytes(s.SubQuery.ser.Bytes())
 }
 
-func (f FlatArrayLen) FunctionType() int {
-	return functionFlatArrayLen
-}
-
-func (f FlatArrayLen) Fields() []string {
-	return []string{f.Field}
-}
-
-func (f FlatArrayLen) Args() []any {
-	return []any{}
-}
-
-func (f Now) FunctionType() int {
-	return functionNow
-}
-
-func (f Now) Fields() []string {
-	return []string{}
-}
-
-func (f Now) Args() []any {
-	return []any{f.TimeUnit}
-}
-
-type IFunction interface {
-	FunctionType() int
-	Fields() []string
-	Args() []any
-}
-
-func SerializeFunction(fn IFunction, ser *cjson.Serializer) {
-	ser.PutVarCUInt(len(fn.Fields()))
-	for _, field := range fn.Fields() {
-		ser.PutVString(field)
-	}
-	ser.PutVarCUInt(len(fn.Args()))
-	for _, arg := range fn.Args() {
-		ser.PutValue(reflect.ValueOf(arg))
-	}
-	ser.PutVarCUInt(fn.FunctionType())
-}
-
 // Type reports expressionTypeExpression for the flat_array_len function node.
 func (f FlatArrayLen) Type() int {
 	return expressionTypeExpression
@@ -137,7 +95,10 @@ func (f FlatArrayLen) Type() int {
 // Serialize writes the function expression tag and flat_array_len payload.
 func (f FlatArrayLen) Serialize(ser *cjson.Serializer) {
 	ser.PutVarCUInt(int(f.Type()))
-	SerializeFunction(f, ser)
+	ser.PutVarCUInt(1)
+	ser.PutVString(f.Field)
+	ser.PutVarCUInt(0)
+	ser.PutVarCUInt(functionFlatArrayLen)
 }
 
 // Type reports expressionTypeExpression for the now function node.
@@ -148,5 +109,8 @@ func (n Now) Type() int {
 // Serialize writes the function expression tag and now() payload.
 func (n Now) Serialize(ser *cjson.Serializer) {
 	ser.PutVarCUInt(int(n.Type()))
-	SerializeFunction(n, ser)
+	ser.PutVarCUInt(0)
+	ser.PutVarCUInt(1)
+	ser.PutVarCUInt(valueString).PutVString(string(n.TimeUnit))
+	ser.PutVarCUInt(functionNow)
 }