magicbot: Fix non-type annotation error for init

magicbot/inject.py

@@ -39,10 +39,12 @@ def get_injection_requests(
 
         # If the type is not actually a type, give a meaningful error
         if not isinstance(inject_type, type):
-            raise TypeError(
-                f"Component {cname} has a non-type annotation {n}: {inject_type}\n"
-                "Lone non-injection variable annotations are disallowed, did you want to assign a static variable?"
+            message = (
+                f"Component {cname} has a non-type annotation {n}: {inject_type!r}"
             )
+            if component is not None:
+                message += "\nLone non-injection variable annotations are disallowed. Did you mean to assign a static variable?"
+            raise TypeError(message)
 
         requests[n] = inject_type
 

tests/test_magicbot_inject.py

@@ -0,0 +1,20 @@
+import typing
+
+import pytest
+
+from magicbot.inject import get_injection_requests
+
+
+def test_ctor_invalid_type_hint_message():
+    """
+    class Component:
+        def __init__(self, foo: 1): ...
+    """
+    type_hints = {
+        "foo": typing.cast(type, 1),
+    }
+
+    with pytest.raises(TypeError) as exc_info:
+        get_injection_requests(type_hints, "bar")
+
+    assert exc_info.value.args[0] == "Component bar has a non-type annotation foo: 1"