Fix printing operation type (#371)

Author: Shane32

src/GraphQLParser.Tests/Visitors/SDLPrinterTests.cs

@@ -813,6 +813,17 @@ public void UTF8_MemoryStream_Runs_Synchronously()
         printer.PrintAsync(document, writer).IsCompletedSuccessfully.ShouldBeTrue();
     }
 
+    [Theory]
+    [InlineData("{ field1 }", "{\n  field1\n}")]
+    [InlineData("query { field1 }", "{\n  field1\n}")]
+    [InlineData("query q1 { field1 }", "query q1 {\n  field1\n}")]
+    [InlineData("mutation { field1 }", "mutation {\n  field1\n}")]
+    [InlineData("mutation m1 { field1 }", "mutation m1 {\n  field1\n}")]
+    public void OperationPrints(string input, string expected)
+    {
+        new SDLPrinter().Print(Parser.Parse(input)).ShouldBe(expected, StringCompareShould.IgnoreLineEndings);
+    }
+
     [Theory]
     [InlineData("query a { name }")]
     [InlineData("directive @skip(if: Boolean!) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT")]

src/GraphQLParser/Visitors/SDLPrinter.cs

@@ -331,11 +331,14 @@ protected override async ValueTask VisitOperationDefinitionAsync(GraphQLOperatio
         }
 
         await VisitAsync(operationDefinition.Comments, context).ConfigureAwait(false);
-        if (operationDefinition.Name is not null)
+        if (operationDefinition.Name is not null || operationDefinition.Operation != OperationType.Query)
         {
             await context.WriteAsync(GetOperationType(operationDefinition.Operation)).ConfigureAwait(false);
             await context.WriteAsync(" ").ConfigureAwait(false);
-            await VisitAsync(operationDefinition.Name, context).ConfigureAwait(false);
+            if (operationDefinition.Name is not null)
+            {
+                await VisitAsync(operationDefinition.Name, context).ConfigureAwait(false);
+            }
         }
         await VisitAsync(operationDefinition.Variables, context).ConfigureAwait(false);
         await VisitAsync(operationDefinition.Directives, context).ConfigureAwait(false);