Python: S5864 FP using type[Enum]

[wieslander (Pär Wieslander)]

• SonarQube Server Enterprise Edition v2025.4.3 (113915)
• Deployed using Docker

I’m getting a false positive for Python static code analysis when trying to dynamically look up the value of a specific key for Enum subclasses. Here’s a simplified example that clearly shows the false positive:

from enum import Enum

def enum_value(enum_class: type[Enum], key: str):
    return enum_class[key]  # FP S5864 on this line

The last line of this file triggers python:S5864 with the error description:

Fix this “_getitem_” operation; Previous type checks suggest that “enum_class” does not have this method.

This is a false positive as enum_class is declared to be a subclass of Enum, and all Enum classes support dynamic key lookup using __getitem__: enum — Support for enumerations — Python 3.14.0 documentation

[ganncamp (G Ann Campbell)]

Hi,

Thanks for this report. We have a ticket in the backlog that I believe matches this. I would give you the link, but the project is private. Here’s the description tho:

S5864: Type check is wrongly interpreted

some_var = generate_some_var()
if type(some_var) is tuple:
    some_var = some_var[0] # FP`

The rule complains with the following message:

Fix this “getitem” operation; Previous type checks suggest that “some_var” does not have this method.sonarqube(python:S5864)

It seems that the rule gets confused with the type check and what the valid operations are.

 
Ann