cloudevents · xSAVIKx · May 23, 2025 · Mar 17, 2025 · Mar 17, 2025 · Mar 17, 2025
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
@@ -17,7 +17,7 @@ jobs:
       - name: Install dev dependencies
         run: python -m pip install -r requirements/dev.txt
       - name: Run linting
-        run: python -m tox -e lint
+        run: python -m tox -e lint,mypy,mypy-samples-image,mypy-samples-json
 
   test:
     strategy:

diff --git a/cloudevents/abstract/event.py b/cloudevents/abstract/event.py
@@ -32,7 +32,7 @@ class CloudEvent:
     @classmethod
     def create(
         cls: typing.Type[AnyCloudEvent],
-        attributes: typing.Dict[str, typing.Any],
+        attributes: typing.Mapping[str, typing.Any],
         data: typing.Optional[typing.Any],
     ) -> AnyCloudEvent:
         """

diff --git a/cloudevents/conversion.py b/cloudevents/conversion.py
@@ -91,7 +91,9 @@ def from_json(
 
 def from_http(
     event_type: typing.Type[AnyCloudEvent],
-    headers: typing.Mapping[str, str],
+    headers: typing.Union[
+        typing.Mapping[str, str], types.SupportsDuplicateItems[str, str]
+    ],
     data: typing.Optional[typing.Union[str, bytes]],
     data_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
 ) -> AnyCloudEvent:
@@ -260,7 +262,7 @@ def best_effort_encode_attribute_value(value: typing.Any) -> typing.Any:
 
 def from_dict(
     event_type: typing.Type[AnyCloudEvent],
-    event: typing.Dict[str, typing.Any],
+    event: typing.Mapping[str, typing.Any],
 ) -> AnyCloudEvent:
     """
     Constructs an Event object of a given `event_type` from

diff --git a/cloudevents/http/conversion.py b/cloudevents/http/conversion.py
@@ -37,7 +37,9 @@ def from_json(
 
 
 def from_http(
-    headers: typing.Dict[str, str],
+    headers: typing.Union[
+        typing.Mapping[str, str], types.SupportsDuplicateItems[str, str]
+    ],
     data: typing.Optional[typing.Union[str, bytes]],
     data_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
 ) -> CloudEvent:
@@ -58,7 +60,7 @@ def from_http(
 
 
 def from_dict(
-    event: typing.Dict[str, typing.Any],
+    event: typing.Mapping[str, typing.Any],
 ) -> CloudEvent:
     """
     Constructs a CloudEvent from a dict `event` representation.

diff --git a/cloudevents/http/event.py b/cloudevents/http/event.py
@@ -34,11 +34,13 @@ class CloudEvent(abstract.CloudEvent):
 
     @classmethod
     def create(
-        cls, attributes: typing.Dict[str, typing.Any], data: typing.Optional[typing.Any]
+        cls,
+        attributes: typing.Mapping[str, typing.Any],
+        data: typing.Optional[typing.Any],
     ) -> "CloudEvent":
         return cls(attributes, data)
 
-    def __init__(self, attributes: typing.Dict[str, str], data: typing.Any = None):
+    def __init__(self, attributes: typing.Mapping[str, str], data: typing.Any = None):
         """
         Event Constructor
         :param attributes: a dict with cloudevent attributes. Minimally

diff --git a/cloudevents/kafka/conversion.py b/cloudevents/kafka/conversion.py
@@ -111,11 +111,29 @@ def to_binary(
     return KafkaMessage(headers, message_key, data)
 
 
+@typing.overload
 def from_binary(
     message: KafkaMessage,
-    event_type: typing.Optional[typing.Type[AnyCloudEvent]] = None,
+    event_type: None = None,
+    data_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
+) -> http.CloudEvent:
+    pass
+
+
+@typing.overload
+def from_binary(
+    message: KafkaMessage,
+    event_type: typing.Type[AnyCloudEvent],
     data_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
 ) -> AnyCloudEvent:
+    pass
+
+
+def from_binary(
+    message: KafkaMessage,
+    event_type: typing.Optional[typing.Type[AnyCloudEvent]] = None,
+    data_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
+) -> typing.Union[http.CloudEvent, AnyCloudEvent]:
     """
     Returns a CloudEvent from a KafkaMessage in binary format.
 
@@ -144,10 +162,11 @@ def from_binary(
         raise cloud_exceptions.DataUnmarshallerError(
             f"Failed to unmarshall data with error: {type(e).__name__}('{e}')"
         )
+    result: typing.Union[http.CloudEvent, AnyCloudEvent]
     if event_type:
         result = event_type.create(attributes, data)
     else:
-        result = http.CloudEvent.create(attributes, data)  # type: ignore
+        result = http.CloudEvent.create(attributes, data)
     return result
 
 
@@ -210,12 +229,32 @@ def to_structured(
     return KafkaMessage(headers, message_key, value)
 
 
+@typing.overload
 def from_structured(
     message: KafkaMessage,
-    event_type: typing.Optional[typing.Type[AnyCloudEvent]] = None,
+    event_type: None = None,
+    data_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
+    envelope_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
+) -> http.CloudEvent:
+    pass
+
+
+@typing.overload
+def from_structured(
+    message: KafkaMessage,
+    event_type: typing.Type[AnyCloudEvent],
     data_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
     envelope_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
 ) -> AnyCloudEvent:
+    pass
+
+
+def from_structured(
+    message: KafkaMessage,
+    event_type: typing.Optional[typing.Type[AnyCloudEvent]] = None,
+    data_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
+    envelope_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
+) -> typing.Union[http.CloudEvent, AnyCloudEvent]:
     """
     Returns a CloudEvent from a KafkaMessage in structured format.
 
@@ -264,8 +303,9 @@ def from_structured(
             attributes["datacontenttype"] = val.decode()
         else:
             attributes[header.lower()] = val.decode()
+    result: typing.Union[AnyCloudEvent, http.CloudEvent]
     if event_type:
         result = event_type.create(attributes, data)
     else:
-        result = http.CloudEvent.create(attributes, data)  # type: ignore
+        result = http.CloudEvent.create(attributes, data)
     return result
diff --git a/cloudevents/pydantic/v1/conversion.py b/cloudevents/pydantic/v1/conversion.py
@@ -21,7 +21,9 @@
 
 
 def from_http(
-    headers: typing.Dict[str, str],
+    headers: typing.Union[
+        typing.Mapping[str, str], types.SupportsDuplicateItems[str, str]
+    ],
     data: typing.Optional[typing.AnyStr],
     data_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
 ) -> CloudEvent:
@@ -63,7 +65,7 @@ def from_json(
 
 
 def from_dict(
-    event: typing.Dict[str, typing.Any],
+    event: typing.Mapping[str, typing.Any],
 ) -> CloudEvent:
     """
     Construct an CloudEvent from a dict `event` representation.

diff --git a/cloudevents/pydantic/v1/event.py b/cloudevents/pydantic/v1/event.py
@@ -100,7 +100,9 @@ class CloudEvent(abstract.CloudEvent, BaseModel):  # type: ignore
 
     @classmethod
     def create(
-        cls, attributes: typing.Dict[str, typing.Any], data: typing.Optional[typing.Any]
+        cls,
+        attributes: typing.Mapping[str, typing.Any],
+        data: typing.Optional[typing.Any],
     ) -> "CloudEvent":
         return cls(attributes, data)
 
@@ -155,7 +157,7 @@ def create(
 
     def __init__(  # type: ignore[no-untyped-def]
         self,
-        attributes: typing.Optional[typing.Dict[str, typing.Any]] = None,
+        attributes: typing.Optional[typing.Mapping[str, typing.Any]] = None,
         data: typing.Optional[typing.Any] = None,
         **kwargs,
     ):

diff --git a/cloudevents/pydantic/v2/conversion.py b/cloudevents/pydantic/v2/conversion.py
@@ -22,7 +22,9 @@
 
 
 def from_http(
-    headers: typing.Dict[str, str],
+    headers: typing.Union[
+        typing.Mapping[str, str], types.SupportsDuplicateItems[str, str]
+    ],
     data: typing.Optional[typing.AnyStr],
     data_unmarshaller: typing.Optional[types.UnmarshallerType] = None,
 ) -> CloudEvent:
@@ -64,7 +66,7 @@ def from_json(
 
 
 def from_dict(
-    event: typing.Dict[str, typing.Any],
+    event: typing.Mapping[str, typing.Any],
 ) -> CloudEvent:
     """
     Construct an CloudEvent from a dict `event` representation.

diff --git a/cloudevents/pydantic/v2/event.py b/cloudevents/pydantic/v2/event.py
@@ -44,7 +44,9 @@ class CloudEvent(abstract.CloudEvent, BaseModel):  # type: ignore
 
     @classmethod
     def create(
-        cls, attributes: typing.Dict[str, typing.Any], data: typing.Optional[typing.Any]
+        cls,
+        attributes: typing.Mapping[str, typing.Any],
+        data: typing.Optional[typing.Any],
     ) -> "CloudEvent":
         return cls(attributes, data)
 
@@ -103,7 +105,7 @@ def create(
 
     def __init__(  # type: ignore[no-untyped-def]
         self,
-        attributes: typing.Optional[typing.Dict[str, typing.Any]] = None,
+        attributes: typing.Optional[typing.Mapping[str, typing.Any]] = None,
         data: typing.Optional[typing.Any] = None,
         **kwargs,
     ):
@@ -173,6 +175,8 @@ def model_validate_json(
         *,
         strict: typing.Optional[bool] = None,
         context: typing.Optional[typing.Dict[str, Any]] = None,
+        by_alias: typing.Optional[bool] = None,
+        by_name: typing.Optional[bool] = None,
     ) -> "CloudEvent":
         return conversion.from_json(cls, json_data)
 

diff --git a/cloudevents/sdk/event/v1.py b/cloudevents/sdk/event/v1.py
@@ -11,10 +11,15 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
+from __future__ import annotations
+
 import typing
 
 from cloudevents.sdk.event import base, opt
 
+if typing.TYPE_CHECKING:
+    from typing_extensions import Self
+
 
 class Event(base.BaseEvent):
     _ce_required_fields = {"id", "source", "type", "specversion"}
@@ -79,39 +84,39 @@ def Extensions(self) -> dict:
             return {}
         return dict(result)
 
-    def SetEventType(self, eventType: str) -> base.BaseEvent:
+    def SetEventType(self, eventType: str) -> Self:
         self.Set("type", eventType)
         return self
 
-    def SetSource(self, source: str) -> base.BaseEvent:
+    def SetSource(self, source: str) -> Self:
         self.Set("source", source)
         return self
 
-    def SetEventID(self, eventID: str) -> base.BaseEvent:
+    def SetEventID(self, eventID: str) -> Self:
         self.Set("id", eventID)
         return self
 
-    def SetEventTime(self, eventTime: typing.Optional[str]) -> base.BaseEvent:
+    def SetEventTime(self, eventTime: typing.Optional[str]) -> Self:
         self.Set("time", eventTime)
         return self
 
-    def SetSubject(self, subject: typing.Optional[str]) -> base.BaseEvent:
+    def SetSubject(self, subject: typing.Optional[str]) -> Self:
         self.Set("subject", subject)
         return self
 
-    def SetSchema(self, schema: typing.Optional[str]) -> base.BaseEvent:
+    def SetSchema(self, schema: typing.Optional[str]) -> Self:
         self.Set("dataschema", schema)
         return self
 
-    def SetContentType(self, contentType: typing.Optional[str]) -> base.BaseEvent:
+    def SetContentType(self, contentType: typing.Optional[str]) -> Self:
         self.Set("datacontenttype", contentType)
         return self
 
-    def SetData(self, data: typing.Optional[object]) -> base.BaseEvent:
+    def SetData(self, data: typing.Optional[object]) -> Self:
         self.Set("data", data)
         return self
 
-    def SetExtensions(self, extensions: typing.Optional[dict]) -> base.BaseEvent:
+    def SetExtensions(self, extensions: typing.Optional[dict]) -> Self:
         self.Set("extensions", extensions)
         return self
 

diff --git a/cloudevents/sdk/types.py b/cloudevents/sdk/types.py
@@ -14,9 +14,25 @@
 
 import typing
 
+_K_co = typing.TypeVar("_K_co", covariant=True)
+_V_co = typing.TypeVar("_V_co", covariant=True)
+
 # Use consistent types for marshal and unmarshal functions across
 # both JSON and Binary format.
 
 MarshallerType = typing.Callable[[typing.Any], typing.AnyStr]
 
 UnmarshallerType = typing.Callable[[typing.AnyStr], typing.Any]
+
+
+class SupportsDuplicateItems(typing.Protocol[_K_co, _V_co]):
+    """
+    Dict-like objects with an items() method that may produce duplicate keys.
+    """
+
+    # This is wider than _typeshed.SupportsItems, which expects items() to
+    # return type an AbstractSet. werkzeug's Headers class satisfies this type,
+    # but not _typeshed.SupportsItems.
+
+    def items(self) -> typing.Iterable[typing.Tuple[_K_co, _V_co]]:
+        pass
diff --git a/cloudevents/tests/test_converters.py b/cloudevents/tests/test_converters.py
@@ -21,7 +21,7 @@
 def test_binary_converter_raise_unsupported():
     with pytest.raises(exceptions.UnsupportedEvent):
         cnvtr = binary.BinaryHTTPCloudEventConverter()
-        cnvtr.read(None, {}, None, None)
+        cnvtr.read(None, {}, None, None)  # type: ignore[arg-type] # intentionally wrong type # noqa: E501
 
 
 def test_base_converters_raise_exceptions():
@@ -35,8 +35,8 @@ def test_base_converters_raise_exceptions():
 
     with pytest.raises(Exception):
         cnvtr = base.Converter()
-        cnvtr.write(None, None)
+        cnvtr.write(None, None)  # type: ignore[arg-type] # intentionally wrong type
 
     with pytest.raises(Exception):
         cnvtr = base.Converter()
-        cnvtr.read(None, None, None, None)
+        cnvtr.read(None, None, None, None)  # type: ignore[arg-type] # intentionally wrong type # noqa: E501
diff --git a/cloudevents/tests/test_event_from_request_converter.py b/cloudevents/tests/test_event_from_request_converter.py
@@ -25,7 +25,7 @@
 @pytest.mark.parametrize("event_class", [v03.Event, v1.Event])
 def test_binary_converter_upstream(event_class):
     m = marshaller.NewHTTPMarshaller([binary.NewBinaryHTTPCloudEventConverter()])
-    event = m.FromRequest(event_class(), data.headers[event_class], None, lambda x: x)
+    event = m.FromRequest(event_class(), data.headers[event_class], b"", lambda x: x)
     assert event is not None
     assert event.EventType() == data.ce_type
     assert event.EventID() == data.ce_id

diff --git a/cloudevents/tests/test_event_pipeline.py b/cloudevents/tests/test_event_pipeline.py
@@ -77,7 +77,7 @@ def test_object_event_v1():
     _, structured_body = m.ToRequest(event)
     assert isinstance(structured_body, bytes)
     structured_obj = json.loads(structured_body)
-    error_msg = f"Body was {structured_body}, obj is {structured_obj}"
+    error_msg = f"Body was {structured_body!r}, obj is {structured_obj}"
     assert isinstance(structured_obj, dict), error_msg
     assert isinstance(structured_obj["data"], dict), error_msg
     assert len(structured_obj["data"]) == 1, error_msg