refactor(shared): add from __future__ import annotations (#4942)

* refactor(shared): add from __future__ import annotations

and update code according to ruff rules TCH, UP006, UP007, UP037 and
FA100.

* Inline if

---------

Co-authored-by: Leandro Damascena <[email protected]>

Author: ericbn

aws_lambda_powertools/shared/cookies.py

@@ -1,7 +1,11 @@
-from datetime import datetime
+from __future__ import annotations
+
 from enum import Enum
 from io import StringIO
-from typing import List, Optional
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from datetime import datetime
 
 
 class SameSite(Enum):
@@ -41,10 +45,10 @@ def __init__(
         domain: str = "",
         secure: bool = True,
         http_only: bool = False,
-        max_age: Optional[int] = None,
-        expires: Optional[datetime] = None,
-        same_site: Optional[SameSite] = None,
-        custom_attributes: Optional[List[str]] = None,
+        max_age: int | None = None,
+        expires: datetime | None = None,
+        same_site: SameSite | None = None,
+        custom_attributes: list[str] | None = None,
     ):
         """
 
@@ -62,13 +66,13 @@ def __init__(
             Marks the cookie as secure, only sendable to the server with an encrypted request over the HTTPS protocol
         http_only: bool
             Enabling this attribute makes the cookie inaccessible to the JavaScript `Document.cookie` API
-        max_age: Optional[int]
+        max_age: int | None
             Defines the period of time after which the cookie is invalid. Use negative values to force cookie deletion.
-        expires: Optional[datetime]
+        expires: datetime | None
             Defines a date where the permanent cookie expires.
-        same_site: Optional[SameSite]
+        same_site: SameSite | None
             Determines if the cookie should be sent to third party websites
-        custom_attributes: Optional[List[str]]
+        custom_attributes: list[str] | None
             List of additional custom attributes to set on the cookie
         """
         self.name = name

aws_lambda_powertools/shared/dynamodb_deserializer.py

@@ -1,5 +1,7 @@
+from __future__ import annotations
+
 from decimal import Clamped, Context, Decimal, Inexact, Overflow, Rounded, Underflow
-from typing import Any, Callable, Dict, Optional, Sequence, Set
+from typing import Any, Callable, Sequence
 
 # NOTE: DynamoDB supports up to 38 digits precision
 # Therefore, this ensures our Decimal follows what's stored in the table
@@ -21,7 +23,7 @@ class TypeDeserializer:
     since we don't support Python 2.
     """
 
-    def deserialize(self, value: Dict) -> Any:
+    def deserialize(self, value: dict) -> Any:
         """Deserialize DynamoDB data types into Python types.
 
         Parameters
@@ -57,7 +59,7 @@ def deserialize(self, value: Dict) -> Any:
         """
 
         dynamodb_type = list(value.keys())[0]
-        deserializer: Optional[Callable] = getattr(self, f"_deserialize_{dynamodb_type}".lower(), None)
+        deserializer: Callable | None = getattr(self, f"_deserialize_{dynamodb_type}".lower(), None)
         if deserializer is None:
             raise TypeError(f"Dynamodb type {dynamodb_type} is not supported")
 
@@ -78,17 +80,17 @@ def _deserialize_s(self, value: str) -> str:
     def _deserialize_b(self, value: bytes) -> bytes:
         return value
 
-    def _deserialize_ns(self, value: Sequence[str]) -> Set[Decimal]:
+    def _deserialize_ns(self, value: Sequence[str]) -> set[Decimal]:
         return set(map(self._deserialize_n, value))
 
-    def _deserialize_ss(self, value: Sequence[str]) -> Set[str]:
+    def _deserialize_ss(self, value: Sequence[str]) -> set[str]:
         return set(map(self._deserialize_s, value))
 
-    def _deserialize_bs(self, value: Sequence[bytes]) -> Set[bytes]:
+    def _deserialize_bs(self, value: Sequence[bytes]) -> set[bytes]:
         return set(map(self._deserialize_b, value))
 
-    def _deserialize_l(self, value: Sequence[Dict]) -> Sequence[Any]:
+    def _deserialize_l(self, value: Sequence[dict]) -> Sequence[Any]:
         return [self.deserialize(v) for v in value]
 
-    def _deserialize_m(self, value: Dict) -> Dict:
+    def _deserialize_m(self, value: dict) -> dict:
         return {k: self.deserialize(v) for k, v in value.items()}

aws_lambda_powertools/shared/functions.py

@@ -8,7 +8,7 @@
 import warnings
 from binascii import Error as BinAsciiError
 from pathlib import Path
-from typing import Any, Dict, Generator, Optional, Union, overload
+from typing import Any, Generator, overload
 
 from aws_lambda_powertools.shared import constants
 
@@ -32,7 +32,7 @@ def strtobool(value: str) -> bool:
     raise ValueError(f"invalid truth value {value!r}")
 
 
-def resolve_truthy_env_var_choice(env: str, choice: Optional[bool] = None) -> bool:
+def resolve_truthy_env_var_choice(env: str, choice: bool | None = None) -> bool:
     """Pick explicit choice over truthy env value, if available, otherwise return truthy env value
 
     NOTE: Environment variable should be resolved by the caller.
@@ -52,27 +52,27 @@ def resolve_truthy_env_var_choice(env: str, choice: Optional[bool] = None) -> bo
     return choice if choice is not None else strtobool(env)
 
 
-def resolve_max_age(env: str, choice: Optional[int]) -> int:
+def resolve_max_age(env: str, choice: int | None) -> int:
     """Resolve max age value"""
     return choice if choice is not None else int(env)
 
 
 @overload
-def resolve_env_var_choice(env: Optional[str], choice: float) -> float: ...
+def resolve_env_var_choice(env: str | None, choice: float) -> float: ...
 
 
 @overload
-def resolve_env_var_choice(env: Optional[str], choice: str) -> str: ...
+def resolve_env_var_choice(env: str | None, choice: str) -> str: ...
 
 
 @overload
-def resolve_env_var_choice(env: Optional[str], choice: Optional[str]) -> str: ...
+def resolve_env_var_choice(env: str | None, choice: str | None) -> str: ...
 
 
 def resolve_env_var_choice(
-    env: Optional[str] = None,
-    choice: Optional[Union[str, float]] = None,
-) -> Optional[Union[str, float]]:
+    env: str | None = None,
+    choice: str | float | None = None,
+) -> str | float | None:
     """Pick explicit choice over env, if available, otherwise return env value received
 
     NOTE: Environment variable should be resolved by the caller.
@@ -136,12 +136,12 @@ def powertools_debug_is_set() -> bool:
     return False
 
 
-def slice_dictionary(data: Dict, chunk_size: int) -> Generator[Dict, None, None]:
+def slice_dictionary(data: dict, chunk_size: int) -> Generator[dict, None, None]:
     for _ in range(0, len(data), chunk_size):
         yield {dict_key: data[dict_key] for dict_key in itertools.islice(data, chunk_size)}
 
 
-def extract_event_from_common_models(data: Any) -> Dict | Any:
+def extract_event_from_common_models(data: Any) -> dict | Any:
     """Extract raw event from common types used in Powertools
 
     If event cannot be extracted, return received data as is.

aws_lambda_powertools/shared/headers_serializer.py

@@ -1,8 +1,11 @@
+from __future__ import annotations
+
 import warnings
 from collections import defaultdict
-from typing import Any, Dict, List, Union
+from typing import TYPE_CHECKING, Any
 
-from aws_lambda_powertools.shared.cookies import Cookie
+if TYPE_CHECKING:
+    from aws_lambda_powertools.shared.cookies import Cookie
 
 
 class BaseHeadersSerializer:
@@ -11,23 +14,23 @@ class BaseHeadersSerializer:
     ALB and Lambda Function URL response payload.
     """
 
-    def serialize(self, headers: Dict[str, Union[str, List[str]]], cookies: List[Cookie]) -> Dict[str, Any]:
+    def serialize(self, headers: dict[str, str | list[str]], cookies: list[Cookie]) -> dict[str, Any]:
         """
         Serializes headers and cookies according to the request type.
         Returns a dict that can be merged with the response payload.
 
         Parameters
         ----------
-        headers: Dict[str, List[str]]
+        headers: dict[str, str | list[str]]
             A dictionary of headers to set in the response
-        cookies: List[str]
+        cookies: list[Cookie]
             A list of cookies to set in the response
         """
         raise NotImplementedError()
 
 
 class HttpApiHeadersSerializer(BaseHeadersSerializer):
-    def serialize(self, headers: Dict[str, Union[str, List[str]]], cookies: List[Cookie]) -> Dict[str, Any]:
+    def serialize(self, headers: dict[str, str | list[str]], cookies: list[Cookie]) -> dict[str, Any]:
         """
         When using HTTP APIs or LambdaFunctionURLs, everything is taken care automatically for us.
         We can directly assign a list of cookies and a dict of headers to the response payload, and the
@@ -39,7 +42,7 @@ def serialize(self, headers: Dict[str, Union[str, List[str]]], cookies: List[Coo
 
         # Format 2.0 doesn't have multiValueHeaders or multiValueQueryStringParameters fields.
         # Duplicate headers are combined with commas and included in the headers field.
-        combined_headers: Dict[str, str] = {}
+        combined_headers: dict[str, str] = {}
         for key, values in headers.items():
             # omit headers with explicit null values
             if values is None:
@@ -54,7 +57,7 @@ def serialize(self, headers: Dict[str, Union[str, List[str]]], cookies: List[Coo
 
 
 class MultiValueHeadersSerializer(BaseHeadersSerializer):
-    def serialize(self, headers: Dict[str, Union[str, List[str]]], cookies: List[Cookie]) -> Dict[str, Any]:
+    def serialize(self, headers: dict[str, str | list[str]], cookies: list[Cookie]) -> dict[str, Any]:
         """
         When using REST APIs, headers can be encoded using the `multiValueHeaders` key on the response.
         This is also the case when using an ALB integration with the `multiValueHeaders` option enabled.
@@ -63,7 +66,7 @@ def serialize(self, headers: Dict[str, Union[str, List[str]]], cookies: List[Coo
         https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html#api-gateway-simple-proxy-for-lambda-output-format
         https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html#multi-value-headers-response
         """
-        payload: Dict[str, List[str]] = defaultdict(list)
+        payload: dict[str, list[str]] = defaultdict(list)
         for key, values in headers.items():
             # omit headers with explicit null values
             if values is None:
@@ -83,14 +86,14 @@ def serialize(self, headers: Dict[str, Union[str, List[str]]], cookies: List[Coo
 
 
 class SingleValueHeadersSerializer(BaseHeadersSerializer):
-    def serialize(self, headers: Dict[str, Union[str, List[str]]], cookies: List[Cookie]) -> Dict[str, Any]:
+    def serialize(self, headers: dict[str, str | list[str]], cookies: list[Cookie]) -> dict[str, Any]:
         """
         The ALB integration has `multiValueHeaders` disabled by default.
         If we try to set multiple headers with the same key, or more than one cookie, print a warning.
 
         https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html#respond-to-load-balancer
         """
-        payload: Dict[str, Dict[str, str]] = {}
+        payload: dict[str, dict[str, str]] = {}
         payload.setdefault("headers", {})
 
         if cookies:

aws_lambda_powertools/shared/json_encoder.py

@@ -13,9 +13,7 @@ class Encoder(json.JSONEncoder):
 
     def default(self, obj):
         if isinstance(obj, decimal.Decimal):
-            if obj.is_nan():
-                return math.nan
-            return str(obj)
+            return math.nan if obj.is_nan() else str(obj)
 
         if is_pydantic(obj):
             return pydantic_to_dict(obj)