Flagsmith/flagsmith

500 when calling /api/v1/features/featurestates/{pk}/ with empty environment

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#6597 opened on Jan 27, 2026

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apigood first issue

Description

Sentry Issue: FLAGSMITH-API-5GQ

AttributeError: 'NoneType' object has no attribute 'id'
(8 additional frame(s) were not displayed)
...
  File "features/serializers.py", line 578, in validate_environment
    if self.instance and self.instance.environment_id != environment.id:  # type: ignore[union-attr]

Acceptance criteria

  • /api/v1/features/featurestates/{pk}/ responds with HTTP 400 if environment is null in the payload.

Contributor guide

Tech stack
pythondjangorest api
Domain
backendapi
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
PythonDjango REST frameworkserializer validation
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
The bug is in features/serializers.py at line 578 in the validate environment method. When environment is null, it tries to access environment.id, causing AttributeError. The fix should add a check for None before accessing id, and return a validation error (HTTP 400) as per acceptance criteria. No linked PRs or comments. The Sentry issue (FLAGSMITH API 5GQ) provides more context.