Merge pull request #1606 from ClickHouse/back_compatible_dynamic_json

Backwards compatible `Dynamic` and `JSON`

Author: SpencerTorres

lib/column/codegen/column.tpl

@@ -122,6 +122,8 @@ func (t Type) Column(name string, sc *ServerContext) (Interface, error) {
 		return &Point{name: name}, nil
 	case "String":
 		return &String{name: name, col: colStrProvider(name)}, nil
+	case "SharedVariant":
+		return &SharedVariant{name: name}, nil
 	case "Object('json')":
 	    return &JSONObject{name: name, root: true, sc: sc}, nil
 	}
@@ -134,9 +136,17 @@ func (t Type) Column(name string, sc *ServerContext) (Interface, error) {
 	case strings.HasPrefix(string(t), "Variant("):
 		return (&Variant{name: name}).parse(t, sc)
 	case strings.HasPrefix(string(t), "Dynamic"):
-		return (&Dynamic{name: name}).parse(t, sc)
+		if sc.VersionMajor >= 25 && sc.VersionMinor >= 6 {
+			return (&Dynamic{name: name}).parse(t, sc)
+		} else {
+			return (&Dynamic_v1{name: name}).parse(t, sc)
+		}
 	case strings.HasPrefix(string(t), "JSON"):
-		return (&JSON{name: name}).parse(t, sc)
+		if sc.VersionMajor >= 25 && sc.VersionMinor >= 6 {
+			return (&JSON{name: name}).parse(t, sc)
+		} else {
+			return (&JSON_v1{name: name}).parse(t, sc)
+		}
 	case strings.HasPrefix(string(t), "Decimal("):
 		return (&Decimal{name: name}).parse(t)
 	case strings.HasPrefix(strType, "Nested("):

lib/column/column_gen.go

@@ -28,7 +28,6 @@ import (
 )
 
 const SupportedDynamicSerializationVersion = 3
-const DeprecatedSupportedDynamicSerializationVersion = 1
 const DefaultMaxDynamicTypes = 32
 const DynamicNullDiscriminator = -1 // The Null index changes as data is being built, use -1 as placeholder for writes.
 
@@ -318,7 +317,7 @@ func (c *Dynamic) decodeHeader(reader *proto.Reader) error {
 		return fmt.Errorf("failed to read dynamic serialization version: %w", err)
 	}
 
-	if dynamicSerializationVersion == DeprecatedSupportedDynamicSerializationVersion {
+	if dynamicSerializationVersion == DeprecatedDynamicSerializationVersion {
 		return fmt.Errorf("deprecated dynamic serialization version: %d, enable \"output_format_native_use_flattened_dynamic_and_json_serialization\" in your settings", dynamicSerializationVersion)
 	} else if dynamicSerializationVersion != SupportedDynamicSerializationVersion {
 		return fmt.Errorf("unsupported dynamic serialization version: %d", dynamicSerializationVersion)