Float Parameter Misinterpreted as Single in Function Invocation

[StephenHodgson]

Discussed in #325

^{Originally posted by @AvatarisAI January 22, 2025}

I recently started using the OpenAI Chat Completions package, and while things are going well overall, I’m encountering an issue with one of my functions.

The function has 5 parameters, one of which is a float. It seems that the framework incorrectly interprets this float value as single, causing the function invocation to fail when calling:
var funcOutput = await toolCall.InvokeFunctionAsync();

I traced the issue to the following line in Runtime/Common/Function.cs (line 477):
var methodParams = function.MethodInfo.GetParameters(); it's in Runtime/Commmon/Function.cs on line 477

Here’s what happens:

1. The creativity parameter is passed with a value of 0.8 (as shown in requestedArgs):
   

2. However, after evaluating function.MethodInfo.GetParameters(), the parameter is interpreted as single:
   

Since the parameter is defined as float in the function signature, this mismatch causes the invocation to fail.

Could you please take a look at this logic and see if there’s a fix?

Thank you!

Exception I get in function: Runtime/Common/Function.cs (line 392):

System.ArgumentException: Object of type 'System.Double' cannot be converted to type 'System.Single'.
  at System.RuntimeType.CheckValue (System.Object value, System.Reflection.Binder binder, System.Globalization.CultureInfo culture, System.Reflection.BindingFlags invokeAttr) [0x00071] in <ed969b0e627d471da4848289f9c322df>:0 
  at System.Reflection.RuntimeMethodInfo.ConvertValues (System.Reflection.Binder binder, System.Object[] args, System.Reflection.ParameterInfo[] pinfo, System.Globalization.CultureInfo culture, System.Reflection.BindingFlags invokeAttr) [0x00069] in <ed969b0e627d471da4848289f9c322df>:0 
  at System.Reflection.RuntimeMethodInfo.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00040] in <ed969b0e627d471da4848289f9c322df>:0 
  at System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) [0x00000] in <ed969b0e627d471da4848289f9c322df>:0 
  at OpenAI.Function.InvokeInternalAsync[T] (OpenAI.Function function, System.Object[] invokeArgs) [0x00012] in .\Library\PackageCache\com.openai.unity\Runtime\Common\Function.cs:443 
  at OpenAI.Function.InvokeAsync (System.Threading.CancellationToken cancellationToken) [0x000c3] in .\Library\PackageCache\com.openai.unity\Runtime\Common\Function.cs:381 

[StephenHodgson]

potential fix for Function.cs:

diff --git forkSrcPrefix/OpenAI/Packages/com.openai.unity/Runtime/Common/Function.cs forkDstPrefix/OpenAI/Packages/com.openai.unity/Runtime/Common/Function.cs
index 4e2e34bb95155c9baacd569de511780cfbca8d0f..256eecdc16dcd31fbcd5339ba0b8ba7026e667f4 100644
--- forkSrcPrefix/OpenAI/Packages/com.openai.unity/Runtime/Common/Function.cs
+++ forkDstPrefix/OpenAI/Packages/com.openai.unity/Runtime/Common/Function.cs
@@ -502,6 +502,11 @@ namespace OpenAI
                     }
                     else
                     {
+                        if (value.GetType() != parameter.ParameterType)
+                        {
+                            value = Convert.ChangeType(value, parameter.ParameterType);
+                        }
+
                         invokeArgs[i] = value;
                     }
                 }