From 9f698543a8b539087889aad4a49649e779d1be84 Mon Sep 17 00:00:00 2001
From: "T. Franzel" <tfranzel@users.noreply.github.com>
Date: Tue, 1 Jun 2021 01:27:33 +0200
Subject: [PATCH] improve type hint detection for Iterable and NamedTuple #404

---
 drf_spectacular/plumbing.py | 15 ++++++++++++---
 tests/test_plumbing.py      | 21 ++++++++++++++++++++-
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/drf_spectacular/plumbing.py b/drf_spectacular/plumbing.py
index 4ac666a3..e9f6fc7d 100644
--- a/drf_spectacular/plumbing.py
+++ b/drf_spectacular/plumbing.py
@@ -1,3 +1,4 @@
+import collections
 import hashlib
 import inspect
 import json
@@ -7,7 +8,6 @@
 import urllib.parse
 from abc import ABCMeta
 from collections import OrderedDict, defaultdict
-from collections.abc import Hashable
 from decimal import Decimal
 from enum import Enum
 from typing import DefaultDict, Generic, List, Optional, Type, TypeVar, Union
@@ -84,7 +84,7 @@ def is_field(obj):
 
 
 def is_basic_type(obj, allow_none=True):
-    if not isinstance(obj, Hashable):
+    if not isinstance(obj, collections.abc.Hashable):
         return False
     if not allow_none and (obj is None or obj is OpenApiTypes.NONE):
         return False
@@ -927,9 +927,16 @@ def resolve_type_hint(hint):
 
     if origin is None and is_basic_type(hint, allow_none=False):
         return build_basic_type(hint)
+    elif origin is None and inspect.isclass(hint) and issubclass(hint, tuple):
+        # a convoluted way to catch NamedTuple. suggestions welcome.
+        if typing.get_type_hints(hint):
+            properties = {k: resolve_type_hint(v) for k, v in typing.get_type_hints(hint).items()}
+        else:
+            properties = {k: build_basic_type(OpenApiTypes.ANY) for k in hint._fields}
+        return build_object_type(properties=properties, required=properties.keys())
     elif origin is list or hint is list:
         return build_array_type(
-            resolve_type_hint(args[0]) if args else build_basic_type(OpenApiTypes.OBJECT)
+            resolve_type_hint(args[0]) if args else build_basic_type(OpenApiTypes.ANY)
         )
     elif origin is tuple:
         return build_array_type(
@@ -967,5 +974,7 @@ def resolve_type_hint(hint):
         if type(None) in args:
             schema['nullable'] = True
         return schema
+    elif origin is collections.abc.Iterable:
+        return build_array_type(resolve_type_hint(args[0]))
     else:
         raise UnableToProceedError()
diff --git a/tests/test_plumbing.py b/tests/test_plumbing.py
index 09261638..716217ca 100644
--- a/tests/test_plumbing.py
+++ b/tests/test_plumbing.py
@@ -1,3 +1,4 @@
+import collections
 import json
 import re
 import sys
@@ -83,6 +84,11 @@ def test_detype_patterns_with_module_includes(no_warnings):
     )
 
 
+class NamedTupleB(typing.NamedTuple):
+    a: int
+    b: str
+
+
 TYPE_HINT_TEST_PARAMS = [
     (
         typing.Optional[int],
@@ -95,7 +101,20 @@ def test_detype_patterns_with_module_includes(no_warnings):
         {'type': 'array', 'items': {'type': 'object', 'additionalProperties': {'type': 'integer'}}}
     ), (
         list,
-        {'type': 'array', 'items': {'type': 'object', 'additionalProperties': {}}}
+        {'type': 'array', 'items': {}}
+    ), (
+        typing.Iterable[collections.namedtuple("NamedTupleA", "a, b")],  # noqa
+        {
+            'type': 'array',
+            'items': {'type': 'object', 'properties': {'a': {}, 'b': {}}, 'required': ['a', 'b']}
+        }
+    ), (
+        NamedTupleB,
+        {
+            'type': 'object',
+            'properties': {'a': {'type': 'integer'}, 'b': {'type': 'string'}},
+            'required': ['a', 'b']
+        }
     ), (
         typing.Tuple[int, int, int],
         {'type': 'array', 'items': {'type': 'integer'}, 'minLength': 3, 'maxLength': 3}