fix: include experiment key on local-eval exposure events#67
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Local evaluation exposure events emit `metadata.experimentKey` inside the metadata blob but never lift it onto a top-level event property. Custom reports keying off `[Experiment] Experiment Key` therefore see no value for customers using local evaluation. When `variant.metadata['experimentKey']` is present, set `event_properties['[Experiment] Experiment Key']`. Mirrors the equivalent fix in the Node SDK (amplitude/experiment-node-server#83). Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
kyeh-amp
approved these changes
May 7, 2026
kyeh-amp
approved these changes
May 7, 2026
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Summary
Exposure::toEvents()carriedexperimentKeyonly inside themetadatablob — the top-level event property[Experiment] Experiment Keywas never set, so custom reports keying off it saw no value for local-eval customers.variant->metadata['experimentKey']is truthy, setevent->eventProperties['[Experiment] Experiment Key']. Additive and backwards-compatible —metadata,[Experiment] Flag Key,[Experiment] Variant, user properties, andinsertIdare unchanged.Test plan
with_experiment_keyfixture toExposureServiceTest::testToEventsCreatesOneEventPerFlag. Asserts[Experiment] Experiment Keyequals'exp-1'for that flag and is absent for the others.vendor/bin/phpunit tests/Exposure/ExposureServiceTest.php— 2 tests, 70 assertions, all pass.🤖 Generated with Claude Code
Note
Low Risk
Low risk: additive event-property change gated on existing
metadata['experimentKey'], with a focused unit test update.Overview
Local-eval
Exposure::toEvents()now copiesvariant->metadata['experimentKey']onto a top-level event property,"[Experiment] Experiment Key", when present (while still including the fullmetadatablob).Tests extend
ExposureServiceTest::testToEventsCreatesOneEventPerFlagwith a newwith_experiment_keyfixture, update the expected event count, and assert the property is set only for that flag and absent otherwise.Reviewed by Cursor Bugbot for commit 79da2e9. Bugbot is set up for automated code reviews on this repo. Configure here.