fix: Retry flags requests on 502 and 504

[marandaneto]

💡 Motivation and Context

Remote feature flag evaluation uses /flags/?v=2. The SDK already retries transient curl/network failures using feature_flag_request_max_retries; this extends that same retry loop to retry HTTP 502 and 504 responses for the flags endpoint only.

This does not change capture/batch retry behavior, and non-retryable flags HTTP statuses such as 408, 429, and 500 remain non-retryable.

💚 How did you test it?

• composer install --no-interaction --prefer-dist
• ./vendor/bin/phpunit --no-coverage --filter 'testFlagsRequest(RetriesHttp502And504|DoesNotRetryHttp502And504WhenConfiguredMaxRetriesIsZero|DoesNotRetryHttpStatusErrors|RetriesTransientCurlErrors|StopsAfterExhaustingTransientCurlErrorRetries|DoesNotRetryWhenConfiguredMaxRetriesIsZero|DoesNotRetryConnectionRefused)' test/FeatureFlagTest.php
• ./vendor/bin/phpunit --no-coverage --filter 'testFlagsRequest(RetriesHttp502And504|DoesNotRetryHttp502And504WhenConfiguredMaxRetriesIsZero)' test/FeatureFlagTest.php
• php -l lib/Client.php && php -l lib/PostHog.php && php -l test/FeatureFlagTest.php
• ./vendor/bin/phpcs lib/Client.php lib/PostHog.php test/FeatureFlagTest.php (0 errors; existing warnings remain)

📝 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 pnpm changeset to generate a changeset file

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Implemented with an AI coding agent in response to a human-directed request. The change was kept to the flags request path: HTTP 502/504 now reuse the existing feature flag retry budget, while transient curl retry behavior is preserved and other HTTP status errors remain non-retryable.

[greptile-apps]

_{Reviews (1): Last reviewed commit: "fix: retry flags requests on 502 and 504" | Re-trigger Greptile}

[github-actions]

posthog-php Compliance Report

Date: 2026-07-02 11:46:42 UTC
Duration: 95089ms

✅ All Tests Passed!

45/45 tests passed

---

Capture Tests

✅ 29/29 tests passed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	11ms
Format Validation.Event Has Uuid	✅	6ms
Format Validation.Event Has Lib Properties	✅	6ms
Format Validation.Distinct Id Is String	✅	6ms
Format Validation.Token Is Present	✅	6ms
Format Validation.Custom Properties Preserved	✅	6ms
Format Validation.Event Has Timestamp	✅	5ms
Retry Behavior.Retries On 503	✅	5315ms
Retry Behavior.Does Not Retry On 400	✅	2009ms
Retry Behavior.Does Not Retry On 401	✅	2010ms
Retry Behavior.Respects Retry After Header	✅	8015ms
Retry Behavior.Implements Backoff	✅	15725ms
Retry Behavior.Retries On 500	✅	5114ms
Retry Behavior.Retries On 502	✅	5114ms
Retry Behavior.Retries On 504	✅	5114ms
Retry Behavior.Max Retries Respected	✅	16528ms
Deduplication.Generates Unique Uuids	✅	11ms
Deduplication.Preserves Uuid On Retry	✅	5113ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	10312ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	5116ms
Deduplication.No Duplicate Events In Batch	✅	11ms
Deduplication.Different Events Have Different Uuids	✅	7ms
Compression.Sends Gzip When Enabled	✅	6ms
Batch Format.Uses Proper Batch Structure	✅	6ms
Batch Format.Flush With No Events Sends Nothing	✅	3ms
Batch Format.Multiple Events Batched Together	✅	11ms
Error Handling.Does Not Retry On 403	✅	2007ms
Error Handling.Does Not Retry On 413	✅	2009ms
Error Handling.Retries On 408	✅	5113ms

Feature_Flags Tests

✅ 16/16 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	6ms
Request Payload.Flags Request Uses V2 Query Param	✅	5ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	4ms
Request Payload.Flags Request Omits Authorization Header	✅	5ms
Request Payload.Token In Flags Body Matches Init	✅	4ms
Request Payload.Groups Round Trip	✅	5ms
Request Payload.Groups Default To Empty Object	✅	5ms
Request Payload.Person Properties Distinct Id Auto Populated When Caller Omits It	✅	4ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	5ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	4ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	5ms
Request Lifecycle.No Flags Request On Init Alone	✅	2ms
Request Lifecycle.No Flags Request On Normal Capture	✅	6ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	7ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	5ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	6ms

[greptile-apps]

_{Reviews (2): Last reviewed commit: "chore: add flags retry changeset" | Re-trigger Greptile}