From aa7eb8751621d3bb35fd633422f5828cfae76fe4 Mon Sep 17 00:00:00 2001
From: Muhammad Azeez <muhammad@dylibso.com>
Date: Mon, 20 Nov 2023 14:36:35 +0300
Subject: [PATCH] fix: fail the build with a descriptive error message when the
 users tries to export functions with parameters

---
 src/Extism.Pdk.MSBuild/FFIGenerator.cs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/Extism.Pdk.MSBuild/FFIGenerator.cs b/src/Extism.Pdk.MSBuild/FFIGenerator.cs
index 9674df1..426ebbd 100644
--- a/src/Extism.Pdk.MSBuild/FFIGenerator.cs
+++ b/src/Extism.Pdk.MSBuild/FFIGenerator.cs
@@ -149,6 +149,12 @@ void extism_print_exception(MonoObject* exc)
 
                 foreach (var method in exportedMethods)
                 {
+                    if (method.Parameters.Count > 0)
+                    {
+                        var parameterNames = string.Join(",", method.Parameters.Select(p => $"{p.ParameterType.Name} {p.Name}"));
+                        _logError($"Extism doesn't support exporting functions that have parameters: {method.DeclaringType.FullName}.{method.Name}({parameterNames})");
+                    }
+
                     var assemblyFileName = method.Module.Assembly.Name.Name + ".dll";
                     var attribute = method.CustomAttributes.First(a => a.AttributeType.Name == "UnmanagedCallersOnlyAttribute");