Add warning log for local flag evaluation cold start#452
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When feature_enabled() is called with only_evaluate_locally=True before flag definitions are fetched, the SDK silently returns None. This adds a warning log so users can diagnose the issue immediately. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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posthog-python Compliance ReportDate: 2026-03-05 21:26:34 UTC ✅ All Tests Passed!29/29 tests passed Capture Tests✅ 29/29 tests passed View Details
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gustavohstrassburger
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Mar 5, 2026
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Both AI comments seems legit though.
The warning was in _locally_evaluate_flag which runs for all flag evaluations, including those that fall back to server-side evaluation. Move it to the caller where only_evaluate_locally is known, so it only fires when the caller explicitly opted out of the server fallback.
Use `is None` instead of `not` to avoid firing when flags are loaded but empty (401, 402, no personal_api_key), which already have their own specific error logs.
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Summary
feature_enabled()is called withonly_evaluate_locally=Truebefore feature flag definitions have been fetched, the SDK silently returnsNone. This adds a warning log so users can diagnose the issue immediately instead of debugging SDK internals.Context
Discovered when debugging a "cold start" issue in a Django shell on a production pod. The first call to
feature_enabled(..., only_evaluate_locally=True)returnedNonebecause the initial HTTP fetch of flag definitions hadn't completed (or failed silently). The second call worked fine because the poller had since fetched the flags.The existing error path in
_fetch_feature_flags_from_apialready logs when the fetch itself fails, but there was no log at the point whereNoneis actually returned to the caller.Test plan
self.feature_flagsis falsy (not loaded yet)