rspec/rules/S5655/python/rule.adoc

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The CPython interpreter does not check arguments type when functions are called. However a function can express the type it expects for each argument in its documentation or by using https://www.python.org/dev/peps/pep-0484/[Type Hints]. Calling such a function with an argument of a different type can easily create a bug. Even if it works right now it can fail later when APIs evolve or when type checks are added (ex: with ``++isinstance++``).
This rule raises an issue when a function or method is called with an argument of a different type than the one described in its type annotations. It also checks argument types for builtin functions.
== Noncompliant Code Example
----
def func(var: str):
pass
func(42) # Noncompliant
len(1) # Noncompliant
----
== Compliant Solution
----
def func(var: str):
pass
func("42")
len("1")
----
== See
* https://docs.python.org/3/library/functions.html#built-in-funcs[Python documentation - builtins]
* https://www.python.org/dev/peps/pep-0484/[PEP 484 — Type Hints]
* https://docs.python.org/3/library/typing.html[Python documentation - typing — Support for type hints]
ifdef::env-github,rspecator-view[]
'''
== Implementation Specification
(visible only on this page)
include::message.adoc[]
include::highlighting.adoc[]
endif::env-github,rspecator-view[]