Merge pull request #110 from byme8/feature/constants

Add support for C# constants

src/ZeroQL.SourceGenerators/Resolver/GraphQLConstantResolver.cs

@@ -0,0 +1,36 @@
+using System.Linq;
+using Microsoft.CodeAnalysis;
+
+namespace ZeroQL.SourceGenerators.Resolver;
+
+public static class GraphQLConstantResolver
+{
+    public static string ToGraphQL(ITypeSymbol symbol, object value) =>
+        symbol switch
+        {
+            { SpecialType: SpecialType.System_String } => $@"""{value}""",
+            { TypeKind: TypeKind.Enum } => MaterializeEnum(symbol, value),
+            _ => value.ToString(),
+        };
+
+    private static string MaterializeEnum(ITypeSymbol symbol, object value)
+    {
+        if (symbol is not INamedTypeSymbol enumType)
+        {
+            return value.ToString();
+        }
+
+        var graphQLName = enumType
+            .GetMembers()
+            .OfType<IFieldSymbol>()
+            .FirstOrDefault(o => o.ConstantValue?.Equals(value) ?? false)
+            ?.GetAttributes()
+            .FirstOrDefault(o => o.AttributeClass?.Name == "GraphQLNameAttribute")
+            ?.ConstructorArguments
+            .FirstOrDefault()
+            .Value?
+            .ToString();
+
+        return graphQLName!;
+    }
+}

src/ZeroQL.SourceGenerators/Resolver/GraphQLQueryResolver.cs

@@ -434,6 +434,11 @@ private static Result<string> HandleArgumentAsVariable(GraphQLResolveContext con
                         return Failed(identifierName, Descriptors.GraphQLVariableShouldBeLocal);
                     }
 
+                    case ILocalSymbol { HasConstantValue: true } localSymbol:
+                    {
+                        var constantValue = localSymbol.ConstantValue!;
+                        return GraphQLConstantResolver.ToGraphQL(localSymbol.Type, constantValue);
+                    }
                     case ILocalSymbol localSymbol:
                     {
                         var graphQLType = parameter.ToGraphQLType();

src/ZeroQL.Tests/Core/TestExtensions.cs

@@ -98,7 +98,9 @@ public static async Task<byte[]> CompileToRealAssemblyAsBytes(this Project proje
 
         if (error != null)
         {
-            throw new Exception(error.GetMessage());
+            var message = error.GetMessage();
+            var preview = error.Location.Preview();
+            throw new Exception($"{message} {preview}");
         }
 
         using var memoryStream = new MemoryStream();
@@ -177,4 +179,19 @@ public static SettingsTask Track(this SettingsTask settingsTask, string value, [
         settingsTask.AddScrubber(o => o.Replace(value, name));
         return settingsTask;
     }
+
+    public static string Preview(this Location location)
+    {
+        var sourceTree = location.SourceTree!;
+        var span = location.GetLineSpan();
+        var line = span.StartLinePosition.Line;
+        var character = span.StartLinePosition.Character;
+        var source = sourceTree
+            .ToString()
+            .Split('\r', '\n');
+
+        var lineWithPreview = source[line].Insert(character, "^");
+
+        return lineWithPreview;
+    }
 }

src/ZeroQL.Tests/SourceGeneration/QueryTests.SupportForConstants.verified.txt

@@ -0,0 +1,6 @@
+{
+  Query: mutation { addUser(firstName: "John", lastName: "Smith") { id } },
+  Data: {
+    Value: 10
+  }
+}

src/ZeroQL.Tests/SourceGeneration/QueryTests.SupportForEnumConstants.verified.txt

@@ -0,0 +1,4 @@
+{
+  Query: mutation { addUserKindPascal(userKindPascal: Good)},
+  Data: 12
+}

src/ZeroQL.Tests/SourceGeneration/QueryTests.cs

@@ -180,14 +180,7 @@ public async Task QueryPreviewGenerated()
             .Where(o => o.Location.SourceTree!.ToString().Contains("Program"))
             .First(o => o.Id == Descriptors.GraphQLQueryPreview.Id);
 
-        var startLinePosition = queryPreview.Location.GetLineSpan().StartLinePosition;
-        var line = startLinePosition.Line;
-        var character = startLinePosition.Character;
-        var source = queryPreview.Location.SourceTree!
-            .ToString()
-            .Split('\r', '\n');
-
-        var lineWithPreview = source[line].Insert(character, "^");
+        var lineWithPreview = queryPreview.Location.Preview();
 
         await Verify(lineWithPreview);
     }
@@ -432,6 +425,39 @@ public async Task SupportForVariablesPassedViaClosure()
 
         await Verify(response);
     }
+
+    [Fact]
+    public async Task SupportForConstants()
+    {
+        var csharpQuery = """
+                          const string firstName = "John";
+                          const string lastName = "Smith";
+                          var response = await qlClient.Mutation(m => m.AddUser(firstName, lastName, o => o.Id));
+                          """;
+
+        var project = await TestProject.Project
+            .ReplacePartOfDocumentAsync("Program.cs", (TestProject.FullLine, csharpQuery));
+
+        var response = await project.Execute();
+
+        await Verify(response);
+    }
+
+    [Fact]
+    public async Task SupportForEnumConstants()
+    {
+        var csharpQuery = """
+                          const UserKindPascal kind = UserKindPascal.Good;
+                          var response = await qlClient.Mutation(m => m.AddUserKindPascal(kind));
+                          """;
+
+        var project = await TestProject.Project
+            .ReplacePartOfDocumentAsync("Program.cs", (TestProject.FullLine, csharpQuery));
+
+        var response = await project.Execute();
+
+        await Verify(response);
+    }
 
     [Fact]
     public async Task NamedArgumentsAreSupported()