fix: chain beforeSend hooks - #697
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…of dropping `buildEvent()` in `PostHogStateless` called `beforeSend.run(postHogEvent)` on every loop iteration instead of `beforeSend.run(eventChecked)`, so with 2+ registered hooks each one transformed the *original* event rather than the previous hook's output — mutations from an earlier hook were invisible to later hooks. A throwing hook also dropped the event outright (`return null`) instead of falling back to the last good value. Both bugs affect `posthog-android` and `posthog-server`, which share this code via `PostHogStateless`. Generated-By: PostHog Desktop Task-Id: ea027967-6134-4b68-bcce-ef6a81e507b0
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posthog-android Compliance ReportDate: 2026-08-19 11:25:11 UTC ✅ All Tests Passed!46/46 tests passed Capture Tests✅ 29/29 tests passed View Details
Feature_Flags Tests✅ 17/17 tests passed View Details
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marandaneto
marked this pull request as ready for review
August 18, 2026 13:59
marandaneto
changed the title
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@PostHog/team-client-libraries pls review if you think this is the right approach |
| "posthog-server": patch | ||
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| Fix `beforeSend` hook chaining in `PostHogStateless.buildEvent()`: when multiple hooks are registered, each hook now receives the previous hook's output instead of the original, pre-chain event, so a mutation made by one hook is visible to the next. Hooks that throw continue to drop the event to avoid enqueueing a potentially unsafe, partially processed payload. Affects both `posthog-android` and `posthog-server`, which share this code path. |
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nit: worth trimming this?
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💡 Motivation and Context
Fixes
beforeSendhook chaining in the sharedPostHogStateless.buildEvent()path used by bothposthog-androidandposthog-server.When multiple hooks were registered, every hook received the original event instead of the previous hook's returned event. Each hook now receives the running value, so replacement events and mutations compose in registration order.
If a hook throws, the SDK logs the error and drops the event. This preserves the safer existing behavior: sending an event after a failed redaction or filtering hook could leak PII or enqueue a partially processed payload.
💚 How did you test it?
make checkFormat../gradlew :posthog:test --tests 'com.posthog.PostHogBeforeSendTest' --tests 'com.posthog.PostHogStatelessTest.beforeSend error handling does not crash'.📝 Checklist
If releasing new changes
pnpm changesetto generate a changeset file