chore(mypy): add mypy support to makefile

[michaelbrewer]

Issue #, if available:

• Official support for MyPy powertools-lambda#3

Description of changes:

• Add mypy as a dev dependency
• Add mypy as task in the Makefile
• Put in some initial fixes (mostly just ignore untyped imports)

Example usage

$ make mypy 
poetry run mypy aws_lambda_powertools
aws_lambda_powertools/tracing/extensions.py:11: error: Skipping analyzing "aws_xray_sdk.ext.aiohttp.client": found module but no type hints or library stubs
aws_lambda_powertools/tracing/extensions.py:11: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
aws_lambda_powertools/tracing/base.py:9: error: Argument 1 to "contextmanager" has incompatible type "Callable[[BaseProvider, Any, KwArg(Any)], ContextManager[Any]]"; expected "Callable[..., Iterator[<nothing>]]"
aws_lambda_powertools/tracing/base.py:22: error: Argument 1 to "contextmanager" has incompatible type "Callable[[BaseProvider, Any, KwArg(Any)], AsyncContextManager[Any]]"; expected "Callable[..., Iterator[<nothing>]]"
aws_lambda_powertools/utilities/parameters/base.py:96: error: Incompatible types in assignment (expression has type "Union[Dict[Any, Any], bytes, None]", variable has type "str")
aws_lambda_powertools/utilities/parameters/base.py:154: error: Incompatible types in assignment (expression has type "Dict[str, str]", variable has type "Dict[str, Union[str, bytes, Dict[Any, Any], None]]")
aws_lambda_powertools/utilities/parameters/base.py:154: note: "Dict" is invariant -- see https://mypy.readthedocs.io/en/stable/common_issues.html#variance
aws_lambda_powertools/utilities/parameters/base.py:154: note: Consider using "Mapping" instead, which is covariant in the value type
aws_lambda_powertools/utilities/parameters/base.py:160: error: Incompatible types in assignment (expression has type "str", variable has type "Tuple[str, Optional[str]]")
aws_lambda_powertools/utilities/parameters/base.py:161: error: Argument 1 to "get_transform_method" has incompatible type "Tuple[str, Optional[str]]"; expected "str"
aws_lambda_powertools/utilities/parameters/base.py:165: error: Invalid index type "Tuple[str, Optional[str]]" for "Dict[str, Union[str, bytes, Dict[Any, Any], None]]"; expected type "str"
aws_lambda_powertools/utilities/parameters/base.py:165: error: Argument 1 to "transform_value" has incompatible type "Union[str, bytes, Dict[Any, Any], None]"; expected "str"
aws_lambda_powertools/utilities/parameters/base.py:169: error: Incompatible return value type (got "Dict[str, Union[str, bytes, Dict[Any, Any], None]]", expected "Union[Dict[str, str], Dict[str, Dict[Any, Any]], Dict[str, bytes]]")
aws_lambda_powertools/tracing/tracer.py:19: error: "LazyLoader" has no attribute "core"
aws_lambda_powertools/tracing/tracer.py:509: error: "Callable[..., Any]" has no attribute "__wrapped__"
aws_lambda_powertools/logging/formatter.py:109: error: Cannot assign to a method
aws_lambda_powertools/logging/formatter.py:109: error: Invalid self argument "LambdaPowertoolsFormatter" to attribute function "converter" with type "Callable[[Optional[float]], struct_time]"
aws_lambda_powertools/logging/formatter.py:131: error: Invalid self argument "LambdaPowertoolsFormatter" to attribute function "converter" with type "Callable[[Optional[float]], struct_time]"
aws_lambda_powertools/logging/formatter.py:131: error: Too many arguments
aws_lambda_powertools/logging/formatter.py:184: error: Argument 1 has incompatible type "str"; expected "Dict[Any, Any]"
aws_lambda_powertools/logging/formatter.py:204: error: Item "None" of "Optional[Type[BaseException]]" has no attribute "__name__"
aws_lambda_powertools/utilities/parameters/ssm.py:87: error: Signature of "get" incompatible with supertype "BaseProvider"
aws_lambda_powertools/utilities/data_classes/sqs_event.py:78: error: Return type "Optional[SQSMessageAttribute]" of "__getitem__" incompatible with return type "SQSMessageAttribute" in supertype "dict"
aws_lambda_powertools/utilities/data_classes/sqs_event.py:78: error: Return type "Optional[SQSMessageAttribute]" of "__getitem__" incompatible with return type "SQSMessageAttribute" in supertype "Mapping"
aws_lambda_powertools/utilities/data_classes/sqs_event.py:80: error: Argument 1 to "SQSMessageAttribute" has incompatible type "SQSMessageAttribute"; expected "Dict[str, Any]"
aws_lambda_powertools/logging/logger.py:355: error: Item "None" of "Optional[PowertoolsFormatter]" has no attribute "remove_keys"
aws_lambda_powertools/utilities/idempotency/persistence/base.py:104: error: Argument 1 to "loads" has incompatible type "Optional[str]"; expected "Union[str, bytes]"
aws_lambda_powertools/utilities/idempotency/persistence/base.py:286: error: Unsupported target for indexed assignment ("Optional[LRUDict]")
aws_lambda_powertools/utilities/idempotency/persistence/base.py:291: error: Item "None" of "Optional[LRUDict]" has no attribute "get"
aws_lambda_powertools/utilities/idempotency/persistence/base.py:301: error: Unsupported right operand type for in ("Optional[LRUDict]")
aws_lambda_powertools/utilities/idempotency/persistence/base.py:302: error: Item "None" of "Optional[LRUDict]" has no attribute "__delitem__"
aws_lambda_powertools/middleware_factory/factory.py:121: error: Item "None" of "Optional[Callable[..., Any]]" has no attribute "__qualname__"
Found 29 errors in 10 files (checked 108 source files)
make: *** [mypy] Error 1

Checklist

• Meet tenets criteria
• Update tests
• Update docs
• PR title follows conventional commit semantics

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-commenter]

Codecov Report

Merging #508 (eff22cb) into develop (43b828e) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #508   +/-   ##
========================================
  Coverage    99.90%   99.90%           
========================================
  Files          107      107           
  Lines         4280     4280           
  Branches       212      212           
========================================
  Hits          4276     4276           
  Misses           1        1           
  Partials         3        3           

Impacted Files	Coverage Δ
aws_lambda_powertools/logging/logger.py	100.00% <100.00%> (ø)
aws_lambda_powertools/utilities/validation/base.py	100.00% <100.00%> (ø)

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[heitorlessa]

Let's create a mypy.ini file to best ignore untyped libraries among other features we can enable like a pydantic plugin.

• Config: https://mypy.readthedocs.io/en/stable/config_file.html

Example that we can start with, errors will become easier to read too:

[mypy]
warn_return_any=False
warn_unused_configs=True
no_implicit_optional=True
warn_redundant_casts=True
warn_unused_ignores=True
pretty = True
show_column_numbers = True
show_error_codes = True
show_error_context = True

[mypy-jmespath]
ignore_missing_imports=True

[michaelbrewer]

@heitorlessa no_implicit_optional=True seems a bit strict to me.

[michaelbrewer]

@heitorlessa no_implicit_optional=True seems a bit strict to me.

Before this was an implicit optional

def foo(msg: str = None):
   ...

now it needs to be

from typing import Optional


def foo(msg: Optional[str] = None):
   ...

[heitorlessa]

@heitorlessa no_implicit_optional=True seems a bit strict to me.

Before this was an implicit optional

def foo(msg: str = None):
   ...

now it needs to be

from typing import Optional


def foo(msg: Optional[str] = None):
   ...

This is correct actually. It's the issue that @Nr18 was having too. Challenge with Python is the mutable defaults