From 4608cce8626c05844d082d1a8c6a9afac85388d8 Mon Sep 17 00:00:00 2001
From: Eric Gustin <34000337+EricGustin@users.noreply.github.com>
Date: Fri, 7 Mar 2025 11:46:42 -0800
Subject: [PATCH] Fix parameterized type bug & better error message (#273)

## PR Description
### 1. Bug Fix
A bug was observed where tools that were using [parameterized
generics](https://docs.python.org/3/library/stdtypes.html#types-genericalias)
(e.g., `dict[str, Any]`) for their input parameters or output, then this
would cause the Worker to fail on startup with the error `issubclass()
arg 1 must be a class` for Python3.13+. This error would not occur for
Python versions less than 3.13.

In Python <3.13, parameterized generics would implicitly be treated as
their underlying type (its origin), so it was possible to treat
`dict[str, Any]` as a class and pass it to `issubclass`. This is not the
case for Python 3.13, so we need to explicitly strip the GenericAlias
(e.g., `dict[str, Any]`) down to its origin (e.g., `dict`), before
checking if it is a subclass of `Enum`.

### 2. Better Error Message
When a tool used an unsupported parameter/output type, then Arcade would
display the following message:
```
Failed to start Arcade Worker:
Type error encountered while adding tool get_website_map from arcade_web.tools.firecrawl.
Reason: issubclass() arg 1 must be a class
```

But now it displays
```
Failed to start Arcade Worker:
Error encountered while adding tool get_website_map from arcade_web.tools.firecrawl.
Reason: Unsupported type: tuple[str, str]
```
---
 arcade/arcade/core/catalog.py | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/arcade/arcade/core/catalog.py b/arcade/arcade/core/catalog.py
index e5ffbdc0..d0a1825f 100644
--- a/arcade/arcade/core/catalog.py
+++ b/arcade/arcade/core/catalog.py
@@ -253,6 +253,10 @@ class ToolCatalog(BaseModel):
                     raise ToolDefinitionError(
                         f"Type error encountered while adding tool {tool_name} from {module_name}. Reason: {e}"
                     )
+                except Exception as e:
+                    raise ToolDefinitionError(
+                        f"Error encountered while adding tool {tool_name} from {module_name}. Reason: {e}"
+                    )
 
     def __getitem__(self, name: FullyQualifiedName) -> MaterializedTool:
         return self.get_tool(name)
@@ -623,15 +627,18 @@ def get_wire_type_info(_type: type) -> WireTypeInfo:
 
     type_to_check = inner_type if is_list else _type
 
+    # Strip generic parameters if type_to_check is a parameterized generic
+    actual_type = get_origin(type_to_check) or type_to_check
+
     # Special case: Literal["string1", "string2"] can be enumerated on the wire
     if is_string_literal(type_to_check):
         is_enum = True
         enum_values = [str(e) for e in get_args(type_to_check)]
 
     # Special case: Enum can be enumerated on the wire
-    elif issubclass(type_to_check, Enum):
+    elif issubclass(actual_type, Enum):
         is_enum = True
-        enum_values = [e.value for e in type_to_check]  # type: ignore[union-attr]
+        enum_values = [e.value for e in actual_type]  # type: ignore[union-attr]
 
     return WireTypeInfo(wire_type, inner_wire_type, enum_values if is_enum else None)
 
@@ -732,10 +739,10 @@ def get_wire_type(
         if wire_type:
             return wire_type
 
-    if issubclass(_type, Enum):
+    if isinstance(_type, type) and issubclass(_type, Enum):
         return "string"
 
-    if issubclass(_type, BaseModel):
+    if isinstance(_type, type) and issubclass(_type, BaseModel):
         return "json"
 
     raise ToolDefinitionError(f"Unsupported parameter type: {_type}")