Use Map.Encode path for simple protocol

conn.go

@@ -555,6 +555,9 @@ const (
 	// pgtype.Map.RegisterDefaultPgType. Queries will be rejected that have arguments that are unregistered or ambigious.
 	// e.g. A map[string]string may have the PostgreSQL type json or hstore. Modes that know the PostgreSQL type can use
 	// a map[string]string directly as an argument. This mode cannot.
+	//
+	// It may be necessary to specify the desired type of an argument in the SQL string when it cannot be inferred. e.g.
+	// "SELECT $1::boolean".
 	QueryExecModeExec
 
 	// Use the simple protocol. Assume the PostgreSQL query parameter types based on the Go type of the arguments.
@@ -562,6 +565,9 @@ const (
 	// pgtype.Map.RegisterDefaultPgType. Queries will be rejected that have arguments that are unregistered or ambigious.
 	// e.g. A map[string]string may have the PostgreSQL type json or hstore. Modes that know the PostgreSQL type can use
 	// a map[string]string directly as an argument. This mode cannot.
+	//
+	// This mode uses client side parameter interpolation. All values are quoted and escaped. It may be necessary to
+	// specify the desired type of an argument in the SQL string when it cannot be inferred. e.g. "SELECT $1::boolean".
 	QueryExecModeSimpleProtocol
 )
 

query_test.go

@@ -1418,7 +1418,7 @@ func TestConnSimpleProtocol(t *testing.T) {
 		var actual bool
 		err := conn.QueryRow(
 			context.Background(),
-			"select $1",
+			"select $1::boolean",
 			pgx.QueryExecModeSimpleProtocol,
 			expected,
 		).Scan(&actual)
@@ -1733,7 +1733,7 @@ func TestConnSimpleProtocol(t *testing.T) {
 		var actualString string
 		err := conn.QueryRow(
 			context.Background(),
-			"select $1::int8, $2::float8, $3, $4::bytea, $5::text",
+			"select $1::int8, $2::float8, $3::boolean, $4::bytea, $5::text",
 			pgx.QueryExecModeSimpleProtocol,
 			expectedInt64, expectedFloat64, expectedBool, expectedBytes, expectedString,
 		).Scan(&actualInt64, &actualFloat64, &actualBool, &actualBytes, &actualString)

values.go

@@ -1,12 +1,6 @@
 package pgx
 
 import (
-	"database/sql/driver"
-	"fmt"
-	"math"
-	"reflect"
-	"time"
-
 	"github.com/jackc/pgx/v5/internal/anynil"
 	"github.com/jackc/pgx/v5/internal/pgio"
 	"github.com/jackc/pgx/v5/pgtype"
@@ -18,88 +12,19 @@ const (
 	BinaryFormatCode = 1
 )
 
-// SerializationError occurs on failure to encode or decode a value
-type SerializationError string
-
-func (e SerializationError) Error() string {
-	return string(e)
-}
-
 func convertSimpleArgument(m *pgtype.Map, arg interface{}) (interface{}, error) {
 	if anynil.Is(arg) {
 		return nil, nil
 	}
 
-	if dv, ok := arg.(driver.Valuer); ok {
-		return dv.Value()
+	buf, err := m.Encode(0, TextFormatCode, arg, nil)
+	if err != nil {
+		return nil, err
 	}
-
-	// All these could be handled by m.Encode below. However, that transforms the argument to a string. That could change
-	// the type of the argument. e.g. '42' instead of 42. So standard types are special cased.
-	switch arg := arg.(type) {
-	case float32:
-		return float64(arg), nil
-	case float64:
-		return arg, nil
-	case bool:
-		return arg, nil
-	case time.Duration:
-		return fmt.Sprintf("%d microsecond", int64(arg)/1000), nil
-	case time.Time:
-		return arg, nil
-	case string:
-		return arg, nil
-	case []byte:
-		return arg, nil
-	case int8:
-		return int64(arg), nil
-	case int16:
-		return int64(arg), nil
-	case int32:
-		return int64(arg), nil
-	case int64:
-		return arg, nil
-	case int:
-		return int64(arg), nil
-	case uint8:
-		return int64(arg), nil
-	case uint16:
-		return int64(arg), nil
-	case uint32:
-		return int64(arg), nil
-	case uint64:
-		if arg > math.MaxInt64 {
-			return nil, fmt.Errorf("arg too big for int64: %v", arg)
-		}
-		return int64(arg), nil
-	case uint:
-		if uint64(arg) > math.MaxInt64 {
-			return nil, fmt.Errorf("arg too big for int64: %v", arg)
-		}
-		return int64(arg), nil
+	if buf == nil {
+		return nil, nil
 	}
-
-	if _, found := m.TypeForValue(arg); found {
-		buf, err := m.Encode(0, TextFormatCode, arg, nil)
-		if err != nil {
-			return nil, err
-		}
-		if buf == nil {
-			return nil, nil
-		}
-		return string(buf), nil
-	}
-
-	refVal := reflect.ValueOf(arg)
-	if refVal.Kind() == reflect.Ptr {
-		arg = refVal.Elem().Interface()
-		return convertSimpleArgument(m, arg)
-	}
-
-	if strippedArg, ok := stripNamedType(&refVal); ok {
-		return convertSimpleArgument(m, strippedArg)
-	}
-	return nil, SerializationError(fmt.Sprintf("Cannot encode %T in simple protocol - %T must implement driver.Valuer, pgtype.TextEncoder, or be a native type", arg, arg))
+	return string(buf), nil
 }
 
 func encodeCopyValue(m *pgtype.Map, buf []byte, oid uint32, arg interface{}) ([]byte, error) {
@@ -119,43 +44,3 @@ func encodeCopyValue(m *pgtype.Map, buf []byte, oid uint32, arg interface{}) ([]
 	}
 	return buf, nil
 }
-
-func stripNamedType(val *reflect.Value) (interface{}, bool) {
-	switch val.Kind() {
-	case reflect.Int:
-		convVal := int(val.Int())
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	case reflect.Int8:
-		convVal := int8(val.Int())
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	case reflect.Int16:
-		convVal := int16(val.Int())
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	case reflect.Int32:
-		convVal := int32(val.Int())
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	case reflect.Int64:
-		convVal := int64(val.Int())
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	case reflect.Uint:
-		convVal := uint(val.Uint())
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	case reflect.Uint8:
-		convVal := uint8(val.Uint())
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	case reflect.Uint16:
-		convVal := uint16(val.Uint())
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	case reflect.Uint32:
-		convVal := uint32(val.Uint())
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	case reflect.Uint64:
-		convVal := uint64(val.Uint())
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	case reflect.String:
-		convVal := val.String()
-		return convVal, reflect.TypeOf(convVal) != val.Type()
-	}
-
-	return nil, false
-}