feat: send $release_id from POSTHOG_RELEASE_ID on every event

[ablaszkiewicz]

💡 Motivation and Context

A Ruby app cannot link its error tracking issues to a release. posthog-cli injects the release id into JavaScript bundles, and a Ruby app has no build step to inject into. This is the Ruby counterpart of posthog-python#975.

• The client reads POSTHOG_RELEASE_ID (the id that posthog-cli release resolve prints) and sends it as $release_id on every event.
• On $exception events the server resolves the release by a direct id lookup.
• The value is read once, when the client is created. It is trimmed, and a blank value counts as unset.
• The id is added in Client#enqueue, the one path that capture, capture_exception, identify, group_identify and alias share. before_send runs after it, so it can still change or remove the id.
• An explicit $release_id in the event properties or the request context wins over the env var.
• It stays out of $set and $group_set, so it never becomes a person or group property.

💚 How did you test it?

• 14 new specs: one per event type, person and group properties, explicit string and symbol keys, before_send, trimming, blank and unset values, and minimal $feature_flag_called events.
• Without the lib/ change, 7 of them fail: the five event types, trimming and the minimal event. The others guard against overriding or leaking the id.
• bundle exec rspec (1215 passed) and bundle exec rake public_api:check pass. bundle exec rubocop reports no offense in the changed files.
• End to end against a local PostHog stack: a gem built from this branch, a release from a locally built posthog-cli release resolve, one handled exception, and one plain event. Both events carried $release_id, and the server resolved ruby-release-env@1.0.0 from it. Not tested against production.

The issue page resolves the release that the CLI created:

The event JSON, filtered to release, shows the $release_id that the SDK sent and the $exception_release that the server resolved from it (same id):

📝 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)

Written with Claude Code (Claude Opus 5.5), directed by the PR assignee.

• The behavior follows posthog-python#975, which the assignee reviewed. The deployment side for PostHog's own app is PostHog/posthog#104420.
• The assignee asked for the id on all events, so minimal $feature_flag_called events carry it too. That is the one difference from Python.
• One hook in enqueue was chosen over one per public method, so a new event type cannot miss it.
• The changeset file was written by hand, not with the pnpm changeset command.

🤖 Generated with Claude Code

[github-actions]

posthog-ruby-sync Compliance Report

Date: 2026-09-23T08:34:40.240734+00:00
Duration: 93923ms

⚠️ Some Tests Failed

45/47 tests passed, 2 failed

---

Capture Tests

⚠️ 29/30 tests passed, 1 failed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	9ms
Format Validation.Event Has Uuid	✅	7ms
Format Validation.Event Has Lib Properties	✅	6ms
Format Validation.Distinct Id Is String	✅	8ms
Format Validation.Token Is Present	✅	5ms
Format Validation.Custom Properties Preserved	✅	6ms
Format Validation.Event Has Timestamp	✅	5ms
Format Validation.Non Utc Event Timestamp Is Converted To Utc	✅	6ms
Retry Behavior.Retries On 503	✅	5267ms
Retry Behavior.Does Not Retry On 400	✅	2011ms
Retry Behavior.Does Not Retry On 401	✅	2010ms
Retry Behavior.Respects Retry After Header	✅	8017ms
Retry Behavior.Implements Backoff	✅	15254ms
Retry Behavior.Retries On 500	✅	5114ms
Retry Behavior.Retries On 502	✅	5151ms
Retry Behavior.Retries On 504	✅	5113ms
Retry Behavior.Max Retries Respected	✅	15477ms
Deduplication.Generates Unique Uuids	✅	18ms
Deduplication.Preserves Uuid On Retry	✅	5155ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	10318ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	5121ms
Deduplication.No Duplicate Events In Batch	✅	17ms
Deduplication.Different Events Have Different Uuids	✅	9ms
Compression.Sends Gzip When Enabled	✅	5ms
Batch Format.Uses Proper Batch Structure	✅	5ms
Batch Format.Flush With No Events Sends Nothing	✅	3ms
Batch Format.Multiple Events Batched Together	❌	19ms
Error Handling.Does Not Retry On 403	✅	2009ms
Error Handling.Does Not Retry On 413	✅	2010ms
Error Handling.Retries On 408	✅	5165ms

Failures

batch_format.multiple_events_batched_together

Expected 1 requests, got 5

Feature_Flags Tests

⚠️ 16/17 tests passed, 1 failed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	9ms
Request Payload.Flags Request Uses V2 Query Param	✅	6ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	6ms
Request Payload.Flags Request Omits Authorization Header	✅	6ms
Request Payload.Token In Flags Body Matches Init	✅	6ms
Request Payload.Groups Round Trip	✅	6ms
Request Payload.Groups Default To Empty Object	✅	6ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	6ms
Request Payload.Disable Geoip Omitted Defaults To False	❌	7ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	6ms
Request Lifecycle.No Flags Request On Init Alone	✅	2ms
Request Lifecycle.No Flags Request On Normal Capture	✅	5ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	9ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	6ms
Retry Behavior.Retries Flags On 502	✅	148ms
Retry Behavior.Retries Flags On 504	✅	137ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	9ms

Failures

request_payload.disable_geoip_omitted_defaults_to_false

Field 'geoip_disable' not found in /flags request body at path 'geoip_disable'. Available keys: ['distinct_id', 'groups', 'person_properties', 'group_properties', 'flag_keys_to_evaluate', 'token']

[github-actions]

posthog-ruby-async Compliance Report

Date: 2026-09-23T08:34:54.941347+00:00
Duration: 98390ms

⚠️ Some Tests Failed

46/47 tests passed, 1 failed

---

Capture Tests

✅ 30/30 tests passed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	107ms
Format Validation.Event Has Uuid	✅	106ms
Format Validation.Event Has Lib Properties	✅	108ms
Format Validation.Distinct Id Is String	✅	107ms
Format Validation.Token Is Present	✅	106ms
Format Validation.Custom Properties Preserved	✅	107ms
Format Validation.Event Has Timestamp	✅	106ms
Format Validation.Non Utc Event Timestamp Is Converted To Utc	✅	7ms
Retry Behavior.Retries On 503	✅	5311ms
Retry Behavior.Does Not Retry On 400	✅	2110ms
Retry Behavior.Does Not Retry On 401	✅	2110ms
Retry Behavior.Respects Retry After Header	✅	8117ms
Retry Behavior.Implements Backoff	✅	15523ms
Retry Behavior.Retries On 500	✅	5212ms
Retry Behavior.Retries On 502	✅	5211ms
Retry Behavior.Retries On 504	✅	5212ms
Retry Behavior.Max Retries Respected	✅	15623ms
Deduplication.Generates Unique Uuids	✅	114ms
Deduplication.Preserves Uuid On Retry	✅	5211ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	10417ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	5215ms
Deduplication.No Duplicate Events In Batch	✅	111ms
Deduplication.Different Events Have Different Uuids	✅	108ms
Compression.Sends Gzip When Enabled	✅	107ms
Batch Format.Uses Proper Batch Structure	✅	107ms
Batch Format.Flush With No Events Sends Nothing	✅	4ms
Batch Format.Multiple Events Batched Together	✅	114ms
Error Handling.Does Not Retry On 403	✅	2108ms
Error Handling.Does Not Retry On 413	✅	2109ms
Error Handling.Retries On 408	✅	5211ms

Feature_Flags Tests

⚠️ 16/17 tests passed, 1 failed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	108ms
Request Payload.Flags Request Uses V2 Query Param	✅	106ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	106ms
Request Payload.Flags Request Omits Authorization Header	✅	107ms
Request Payload.Token In Flags Body Matches Init	✅	108ms
Request Payload.Groups Round Trip	✅	106ms
Request Payload.Groups Default To Empty Object	✅	106ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	107ms
Request Payload.Disable Geoip Omitted Defaults To False	❌	107ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	106ms
Request Lifecycle.No Flags Request On Init Alone	✅	3ms
Request Lifecycle.No Flags Request On Normal Capture	✅	106ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	112ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	108ms
Retry Behavior.Retries Flags On 502	✅	209ms
Retry Behavior.Retries Flags On 504	✅	244ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	108ms

Failures

request_payload.disable_geoip_omitted_defaults_to_false

Field 'geoip_disable' not found in /flags request body at path 'geoip_disable'. Available keys: ['distinct_id', 'groups', 'person_properties', 'group_properties', 'flag_keys_to_evaluate', 'token']

[greptile-apps]

The PR appears safe to merge with no actionable correctness, security, or repository-rule violations identified.

_{Reviews (1) · Last reviewed commit: "feat: send $release_id from POSTHOG_RELE..."}

[posthog]

🦔 PostHog Review reviewed this pull request

Nothing worth raising this time, so here's a calming picture instead: