Fixed: The SchemaPrinter now correctly prints the 'extend' keyword for type extensions.

src/HotChocolate/Language/src/Language.SyntaxTree/Utilities/SyntaxSerializer.SchemaSyntax.cs

@@ -12,6 +12,8 @@ private void VisitSchemaDefinition(SchemaDefinitionNode node, ISyntaxWriter writ
 
  private void VisitSchemaExtension(SchemaExtensionNode node, ISyntaxWriter writer)
  {
+ writer.Write(Keywords.Extend);
+ writer.WriteSpace();
  VisitSchemaDefinitionBase(node, writer);
  }
 
@@ -40,6 +42,8 @@ private void VisitObjectTypeDefinition(ObjectTypeDefinitionNode node, ISyntaxWri
 
  private void VisitObjectTypeExtension(ObjectTypeExtensionNode node, ISyntaxWriter writer)
  {
+ writer.Write(Keywords.Extend);
+ writer.WriteSpace();
  VisitObjectTypeDefinitionBase(node, writer);
  }
 
@@ -87,6 +91,8 @@ private void VisitInterfaceTypeExtension(
  InterfaceTypeExtensionNode node,
  ISyntaxWriter writer)
  {
+ writer.Write(Keywords.Extend);
+ writer.WriteSpace();
  VisitInterfaceTypeDefinitionBase(node, writer);
  }
 
@@ -134,6 +140,8 @@ private void VisitUnionTypeExtension(
  UnionTypeExtensionNode node,
  ISyntaxWriter writer)
  {
+ writer.Write(Keywords.Extend);
+ writer.WriteSpace();
  VisitUnionTypeDefinitionBase(node, writer);
  }
 
@@ -168,6 +176,8 @@ private void VisitEnumTypeExtension(
  EnumTypeExtensionNode node,
  ISyntaxWriter writer)
  {
+ writer.Write(Keywords.Extend);
+ writer.WriteSpace();
  VisitEnumTypeDefinitionBase(node, writer);
  }
 
@@ -205,6 +215,8 @@ private void VisitInputObjectTypeExtension(
  InputObjectTypeExtensionNode node,
  ISyntaxWriter writer)
  {
+ writer.Write(Keywords.Extend);
+ writer.WriteSpace();
  VisitInputObjectTypeDefinitionBase(node, writer);
  }
 
@@ -242,6 +254,8 @@ private void VisitScalarTypeExtension(
  ScalarTypeExtensionNode node,
  ISyntaxWriter writer)
  {
+ writer.Write(Keywords.Extend);
+ writer.WriteSpace();
  VisitScalarTypeDefinitionBase(node, writer);
  }
 

src/HotChocolate/Language/test/Language.Tests/AST/Utillities/SchemaSyntaxPrinterTests.cs

@@ -157,6 +157,19 @@ public void Serialize_ObjectTypeImplementsXYZWithIndent_OutHasIndentation()
  result.MatchSnapshot();
  }
 
+ [Fact]
+ public void Serialize_ObjectTypeExtensionDef_InOutShouldBeTheSame()
+ {
+ // arrange
+ string schema = "extend type Foo { bar: String baz: [Int] }";
+ DocumentNode document = Utf8GraphQLParser.Parse(schema);
+
+ // act
+ string result = document.ToString(false);
+
+ // assert
+ Assert.Equal(schema, result);
+ }
 
  [Fact]
  public void Serialize_InterfaceTypeDefNoIndent_InOutShouldBeTheSame()
@@ -310,6 +323,19 @@ public void Serialize_InterfaceTypeImplementsXYZWithIndent_OutHasIndentation()
  result.MatchSnapshot();
  }
 
+ [Fact]
+ public void Serialize_InterfaceTypeExtensionDef_InOutShouldBeTheSame()
+ {
+ // arrange
+ string schema = "extend interface Foo { bar: String baz: [Int] }";
+ DocumentNode document = Utf8GraphQLParser.Parse(schema);
+
+ // act
+ string result = document.ToString(false);
+
+ // assert
+ Assert.Equal(schema, result);
+ }
 
  [Fact]
  public void Serialize_UnionTypeDefNoIndent_InOutShouldBeTheSame()
@@ -395,6 +421,20 @@ public void Serialize_UnionTypeDefWithDescriptionNoIndented_OutHasIndentation()
  result.MatchSnapshot();
  }
 
+ [Fact]
+ public void Serialize_UnionTypeExtensionDef_InOutShouldBeTheSame()
+ {
+ // arrange
+ string schema = "extend union A = B | C";
+ DocumentNode document = Utf8GraphQLParser.Parse(schema);
+
+ // act
+ string result = document.ToString(false);
+
+ // assert
+ Assert.Equal(schema, result);
+ }
+
  [Fact]
  public void Serialize_EnumTypeDefNoIndent_InOutShouldBeTheSame()
  {
@@ -479,6 +519,20 @@ public void Serialize_EnumTypeDefWithDescriptionNoIndented_OutHasIndentation()
  result.MatchSnapshot();
  }
 
+ [Fact]
+ public void Serialize_EnumTypeExtensionDef_InOutShouldBeTheSame()
+ {
+ // arrange
+ string schema = "extend enum A { B C }";
+ DocumentNode document = Utf8GraphQLParser.Parse(schema);
+
+ // act
+ string result = document.ToString(false);
+
+ // assert
+ Assert.Equal(schema, result);
+ }
+
  [Fact]
  public void Serialize_InputObjectTypeDefNoIndent_InOutShouldBeTheSame()
  {
@@ -565,6 +619,20 @@ public void Serialize_InputObjectTypeDefWithDescriptionNoIndentt_OutHasIndentati
  result.MatchSnapshot();
  }
 
+ [Fact]
+ public void Serialize_InputObjectTypeExtensionDef_InOutShouldBeTheSame()
+ {
+ // arrange
+ string schema = "extend input A { b: String }";
+ DocumentNode document = Utf8GraphQLParser.Parse(schema);
+
+ // act
+ string result = document.ToString(false);
+
+ // assert
+ Assert.Equal(schema, result);
+ }
+
  [Fact]
  public void Serialize_ScalarTypeDefNoIndent_InOutShouldBeTheSame()
  {
@@ -621,6 +689,20 @@ public void Serialize_ScalarTypeDefWithDescIndent_OutHasIndentation()
  result.MatchSnapshot();
  }
 
+ [Fact]
+ public void Serialize_ScalarTypeExtensionDef_InOutShouldBeTheSame()
+ {
+ // arrange
+ string schema = "extend scalar A @a @b(c: 1)";
+ DocumentNode document = Utf8GraphQLParser.Parse(schema);
+
+ // act
+ string result = document.ToString(false);
+
+ // assert
+ Assert.Equal(schema, result);
+ }
+
  [Fact]
  public void Serialize_SchemaDefWithOpNoIndent_InOutShouldBeTheSame()
  {
@@ -676,5 +758,19 @@ public void Serialize_SchemaDefWithOpAndDirecNoIndent_OutHasIndentation()
  // assert
  result.MatchSnapshot();
  }
+
+ [Fact]
+ public void Serialize_SchemaTypeExtensionDef_InOutShouldBeTheSame()
+ {
+ // arrange
+ string schema = "extend schema { query: A }";
+ DocumentNode document = Utf8GraphQLParser.Parse(schema);
+
+ // act
+ string result = document.ToString(false);
+
+ // assert
+ Assert.Equal(schema, result);
+ }
  }
 }