fix: no-op flag helpers on API errors

[marandaneto]

💡 Motivation and Context

The Python Client-only feature flag helpers should return default values instead of raising when /flags fails because the SDK is non-operational, for example due to an invalid non-empty project API key.

Changes:

• Catch flag API exceptions in Client.get_flags_decision() and return an empty normalized flags response.
• Cover the convenience helpers that depend on get_flags_decision() (get_feature_variants, get_feature_payloads, and get_feature_flags_and_payloads).
• Add a Sampo changeset.

💚 How did you test it?

• uv run pytest posthog/test/test_client.py -q

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.

If releasing new changes

• Ran sampo add to generate a changeset file

[github-actions]

posthog-python Compliance Report

Date: 2026-06-01 07:36:11 UTC
Duration: 176135ms

✅ All Tests Passed!

45/45 tests passed

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Capture Tests

✅ 29/29 tests passed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	518ms
Format Validation.Event Has Uuid	✅	1508ms
Format Validation.Event Has Lib Properties	✅	1507ms
Format Validation.Distinct Id Is String	✅	1507ms
Format Validation.Token Is Present	✅	1507ms
Format Validation.Custom Properties Preserved	✅	1507ms
Format Validation.Event Has Timestamp	✅	1507ms
Retry Behavior.Retries On 503	✅	9519ms
Retry Behavior.Does Not Retry On 400	✅	3506ms
Retry Behavior.Does Not Retry On 401	✅	3508ms
Retry Behavior.Respects Retry After Header	✅	9515ms
Retry Behavior.Implements Backoff	✅	23530ms
Retry Behavior.Retries On 500	✅	7506ms
Retry Behavior.Retries On 502	✅	7513ms
Retry Behavior.Retries On 504	✅	7512ms
Retry Behavior.Max Retries Respected	✅	23519ms
Deduplication.Generates Unique Uuids	✅	1509ms
Deduplication.Preserves Uuid On Retry	✅	7516ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	14521ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	7509ms
Deduplication.No Duplicate Events In Batch	✅	1503ms
Deduplication.Different Events Have Different Uuids	✅	1507ms
Compression.Sends Gzip When Enabled	✅	1508ms
Batch Format.Uses Proper Batch Structure	✅	1507ms
Batch Format.Flush With No Events Sends Nothing	✅	1005ms
Batch Format.Multiple Events Batched Together	✅	1506ms
Error Handling.Does Not Retry On 403	✅	3507ms
Error Handling.Does Not Retry On 413	✅	3508ms
Error Handling.Retries On 408	✅	7516ms

Feature_Flags Tests

✅ 16/16 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	1003ms
Request Payload.Flags Request Uses V2 Query Param	✅	1007ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	1007ms
Request Payload.Flags Request Omits Authorization Header	✅	1007ms
Request Payload.Token In Flags Body Matches Init	✅	1007ms
Request Payload.Groups Round Trip	✅	1007ms
Request Payload.Groups Default To Empty Object	✅	1006ms
Request Payload.Person Properties Distinct Id Auto Populated When Caller Omits It	✅	1006ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	1007ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	1007ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	1007ms
Request Lifecycle.No Flags Request On Init Alone	✅	503ms
Request Lifecycle.No Flags Request On Normal Capture	✅	1507ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	1011ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	1003ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	1509ms

[greptile-apps]

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

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### Issue 1 of 1
posthog/test/test_client.py:107-120
**Non-parameterized test for multiple helpers**

The test bundles four independent assertions in one method, so a failure in the first assertion (e.g. `get_flags_decision`) silences the remaining three. The codebase already uses both `@parameterized.expand` and `subTest` loops for exactly this scenario — see the `test_methods_handle_exceptions` test at line 2825 for a close parallel. Using `subTest` (or `@parameterized.expand`) would let all four helpers run independently and report individually, which is the team's stated preference for parameterised tests.

_{Reviews (1): Last reviewed commit: "fix: preserve flag error handling on fla..." | Re-trigger Greptile}