new environment check for expected pre-built-types

src/GeneratorTarget/Program.cs

@@ -1,5 +1,6 @@
 using System.Threading.Tasks;
 using JasperFx.CodeGeneration;
+using JasperFx.CodeGeneration.Commands;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Oakton;
@@ -17,6 +18,8 @@ static Task<int> Main(string[] args)
                 {
                     services.AddSingleton<ICodeFileCollection>(new GreeterGenerator());
                     services.AddSingleton<ICodeFileCollection>(new GreeterGenerator2());
+                    
+                    services.AssertAllExpectedPreBuiltTypesExistOnStartUp();
                 })
                 .RunOaktonCommands(args);
 

src/JasperFx.CodeGeneration.Commands/AllPreGeneratedTypesExist.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
+using Oakton.Environment;
+
+namespace JasperFx.CodeGeneration.Commands;
+
+public class AllPreGeneratedTypesExist : IEnvironmentCheck
+{
+    public async Task Assert(IServiceProvider services, CancellationToken cancellation)
+    {
+        var collections = services.GetServices<ICodeFileCollection>().ToArray();
+        foreach (var collection in collections)
+        {
+            collection.AssertPreBuildTypesExist(services);
+        }
+    }
+
+    public string Description { get; } =
+        "Asserting that all expected pre-built generated types exist in the configured assembly";
+}

src/JasperFx.CodeGeneration.Commands/CodeAction.cs

@@ -5,6 +5,6 @@ public enum CodeAction
         preview,
         write,
         test,
-        delete
+        delete,
     }
 }

src/JasperFx.CodeGeneration.Commands/GenerateCodeCommand.cs

@@ -51,7 +51,6 @@ public override bool Execute(GenerateCodeInput input)
 
                 case CodeAction.delete:
                     builder.DeleteAllGeneratedCode();
-
                     break;
 
                 case CodeAction.write:

src/JasperFx.CodeGeneration.Commands/VerificationExtensions.cs

@@ -7,6 +7,7 @@
 using JasperFx.RuntimeCompiler;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
+using Oakton.Environment;
 
 namespace JasperFx.CodeGeneration.Commands;
 
@@ -59,4 +60,14 @@ public static void AssertAllGeneratedCodeCanCompile(this IHost host)
             throw new AggregateException($"Compilation failures for:\n{failures.Join("\n")}", exceptions);
         }
     }
+
+    /// <summary>
+    /// Add an environment check that all expected pre-built generated
+    /// types exist in the configured assembly
+    /// </summary>
+    /// <param name="services"></param>
+    public static void AssertAllExpectedPreBuiltTypesExistOnStartUp(this IServiceCollection services)
+    {
+        services.AddSingleton<IEnvironmentCheck, AllPreGeneratedTypesExist>();
+    }
 }

src/JasperFx.CodeGeneration/CodeGenerationExtensions.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Reflection;
@@ -8,6 +9,13 @@
 
 namespace JasperFx.CodeGeneration;
 
+public class MissingTypeException : Exception
+{
+    public MissingTypeException(string? message) : base(message)
+    {
+    }
+}
+
 public static class CodeGenerationExtensions
 {
     /// <summary>
@@ -95,4 +103,32 @@ public static void ReturnNewStringConstant(this FramesCollection frames,
         var setter = frames.ParentMethod.ParentType.AddStringConstant(constantName, value);
         frames.Return(setter);
     }
+
+    /// <summary>
+    /// Assert that all the expected pre-generated types exist in the configured assembly
+    /// </summary>
+    /// <param name="collection"></param>
+    /// <param name="services"></param>
+    /// <exception cref="MissingTypeException"></exception>
+    public static void AssertPreBuildTypesExist(this ICodeFileCollection collection, IServiceProvider services)
+    {
+        var missing = new List<ICodeFile>();
+
+        foreach (var file in collection.BuildFiles())
+        {
+            var @namespace = $"{collection.Rules.GeneratedNamespace}.{collection.ChildNamespace}";
+            if (!file.AttachTypesSynchronously(collection.Rules, collection.Rules.ApplicationAssembly, services,
+                    @namespace))
+            {
+                missing.Add(file);
+            }
+        }
+
+        if (missing.Any())
+        {
+            throw new MissingTypeException(
+                $"Missing expected pre-generated type(s) from assembly {collection.Rules.ApplicationAssembly.FullName}:\n" +
+                missing.Select(x => x.ToString()).Join("\n"));
+        }
+    }
 }