Choices for Str not just list

In the case of the Str (which translates to a StrEnum for choices) the
explicit list isinstance check is incorrect. There are many cases where
it would be valid to send an `Iterable` such as with `dict.keys()`
returning a `dict_keys`. As we do not want to explictly cast to `list`
type this commit results in a check of iterable type instead of list.

python/cog/predictor.py

@@ -8,7 +8,7 @@
 import types
 import uuid
 from abc import ABC, abstractmethod
-from collections.abc import Iterator
+from collections.abc import Iterable, Iterator
 from pathlib import Path
 from typing import (
     Any,
@@ -354,7 +354,7 @@ def get_input_create_model_kwargs(signature: inspect.Signature) -> Dict[str, Any
         # In either case, remove it as an extra field because it will be
         # passed automatically as 'enum' in the schema
         if choices:
-            if InputType == str and isinstance(choices, list):  # noqa: E721
+            if InputType == str and isinstance(choices, Iterable):  # noqa: E721
 
                 class StringEnum(str, enum.Enum):
                     pass

python/tests/server/fixtures/input_choices_iterable.py

@@ -0,0 +1,7 @@
+from cog import BasePredictor, Input
+
+
+class Predictor(BasePredictor):
+    def predict(self, text: str = Input(choices={"foo": "x", "bar": "y"}.keys())) -> str:
+        assert type(text) == str
+        return text

python/tests/server/test_http_input.py

@@ -214,6 +214,14 @@ def test_choices_str(client):
     assert resp.status_code == 422
 
 
+@uses_predictor("input_choices_iterable")
+def test_choices_str(client):
+    resp = client.post("/predictions", json={"input": {"text": "foo"}})
+    assert resp.status_code == 200
+    resp = client.post("/predictions", json={"input": {"text": "baz"}})
+    assert resp.status_code == 422
+
+
 @uses_predictor("input_choices_integer")
 def test_choices_int(client):
     resp = client.post("/predictions", json={"input": {"x": 1}})

python/tests/server/test_predictor.py

@@ -14,6 +14,7 @@
 PREDICTOR_FIXTURES = [
     ("input_choices", "Predictor", "predict"),
     ("input_choices_integer", "Predictor", "predict"),
+    ("input_choices_iterable", "Predictor", "predict"),
     ("input_file", "Predictor", "predict"),
     ("function", "predict", "predict"),
     ("input_ge_le", "Predictor", "predict"),