Disable Literal support for Python 3.8

python/cog/command/ast_openapi_schema.py

@@ -357,19 +357,11 @@ def get_annotation(node: "ast.AST | None") -> str:
         return node.value  # e.g. arg: "Path"
     if isinstance(node, ast.Subscript):
         value = get_annotation(node.value)
-        if value == "Literal":
-            if sys.version_info < (3, 9):
-                elts = (
-                    node.slice.elts
-                    if isinstance(node.slice, ast.Tuple)
-                    else [node.slice]
-                )
-            else:
-                elts = (
-                    node.slice.elts
-                    if isinstance(node.slice, ast.Tuple)
-                    else [node.slice]
-                )
+        # Literal is unsupported in Python 3.8 and earlier
+        if value == "Literal" and sys.version_info > (3, 8):
+            elts = (
+                node.slice.elts if isinstance(node.slice, ast.Tuple) else [node.slice]
+            )
             return f"Literal[{','.join(repr(get_value(e)) for e in elts)}]"
         # ignore other Subscript (Optional[str]), BinOp (str | int), and stuff like that
     raise ValueError("Unexpected annotation type", type(node))

python/tests/server/test_http.py

@@ -1,8 +1,10 @@
 import base64
 import io
+import sys
 import time
 import unittest.mock as mock
 
+import pytest
 import responses
 from PIL import Image
 from responses import matchers
@@ -370,6 +372,9 @@ def test_train_openapi_specification(client):
     }
 
 
+@pytest.mark.skipif(
+    sys.version_info < (3, 9), reason="Literal is unsupported in Python 3.8 and earlier"
+)
 @uses_predictor("input_literal")
 def test_openapi_specification_with_literal(client, static_schema):
     resp = client.get("/openapi.json")

python/tests/server/test_http_input.py

@@ -1,7 +1,9 @@
 import base64
 import os
+import sys
 import threading
 
+import pytest
 import responses
 
 from cog import schema
@@ -196,6 +198,9 @@ def test_choices_int(client):
     assert resp.status_code == 422
 
 
+@pytest.mark.skipif(
+    sys.version_info < (3, 9), reason="Literal is unsupported in Python 3.8 and earlier"
+)
 @uses_predictor("input_literal")
 def test_literal_str(client):
     resp = client.post("/predictions", json={"input": {"text": "foo"}})
@@ -204,6 +209,9 @@ def test_literal_str(client):
     assert resp.status_code == 422
 
 
+@pytest.mark.skipif(
+    sys.version_info < (3, 9), reason="Literal is unsupported in Python 3.8 and earlier"
+)
 @uses_predictor("input_literal_integer")
 def test_literal_int(client):
     resp = client.post("/predictions", json={"input": {"x": 1}})