feat: send error tracking stack frames in canonical bottom-up order

[cat-ph]

Problem

PostHog SDKs disagree on the order of stack frames inside $exception_list[].stacktrace.frames. posthog-go currently emits frames in Go's native runtime.CallersFrames order (innermost first, crash/capture site at index 0), while the canonical cross-SDK convention being standardized in PostHog/sdk-specs#11 is bottom-up: entry point first, crash site last. Mixed conventions make the same logical error group, fingerprint, and display differently per platform.

Changes

• DefaultStackTraceExtractor.GetStackTrace reverses the collected frames after the runtime.CallersFrames loop, emitting canonical wire order (frames[0] = outermost/entry point, last = capture site). This matches the already-canonical NativeStackTraceExtractor.
• The single-element $exception_list behavior is unchanged.
• Changeset with a minor bump.

Tests

• Reversed the ordered expectations in the four existing table cases and updated the skip/cap case names and comments (skip drops the tail now; the 64-frame cap drops the head).
• New regression test TestDefaultStackTraceExtractor_CanonicalWireOrder: first frame = entry point (runtime.goexit), last frame = capture site (runtime.Callers).
• go build ./..., go vet ./..., focused error-tracking suite: 31 passed.

Coordination

This is a breaking wire-order change. Do not merge/release until the ingestion pipeline's normalization gate (cymbal) is live; it gates legacy payloads per $lib/$lib_version, so this must ship as a minor release. Part of the cross-SDK ordering standardization tracked in PostHog/sdk-specs#11.

[github-actions]

posthog-go Compliance Report

Date: 2026-07-03 00:16:52 UTC
Duration: 169149ms

⚠️ Some Tests Failed

109/111 tests passed, 2 failed

---

Capture_V1 Tests

✅ 94/94 tests passed

View Details

Test	Status	Duration
Endpoint And Method.Targets V1 Endpoint	✅	25ms
Endpoint And Method.Does Not Use Legacy Endpoints	✅	5ms
Required Headers.Has Authorization Bearer Header	✅	6ms
Required Headers.Has Content Type Json	✅	5ms
Required Headers.Has Posthog Sdk Info Format	✅	6ms
Required Headers.Has Posthog Attempt Header	✅	5ms
Required Headers.Has Posthog Request Id	✅	6ms
Required Headers.Has Posthog Request Timestamp	✅	6ms
Required Headers.Has User Agent	✅	6ms
Body Format.Body Has Created At And Batch	✅	6ms
Body Format.No Api Key In Body	✅	6ms
Body Format.No Sent At In Body	✅	5ms
Event Format.Event Has Required Root Fields	✅	6ms
Event Format.Event Uuid Is Valid	✅	6ms
Event Format.Event Timestamp Is Rfc3339	✅	6ms
Event Format.Distinct Id Is String	✅	6ms
Event Format.Distinct Id At Root Not Properties	✅	5ms
Event Format.Custom Properties Preserved	✅	6ms
Event Format.Set Properties Preserved	✅	6ms
Event Format.Set Once Properties Preserved	✅	6ms
Event Format.Groups Properties Preserved	✅	16ms
Event Format.Sdk Generates Uuid If Not Provided	✅	6ms
Event Format.Event Has Required Root Fields Batch	✅	8ms
Event Format.Event Uuid Is Valid Batch	✅	8ms
Event Format.Event Timestamp Is Rfc3339 Batch	✅	8ms
Event Format.Distinct Id Is String Batch	✅	9ms
Event Format.Distinct Id At Root Not Properties Batch	✅	8ms
Event Format.Custom Properties Preserved Batch	✅	8ms
Event Format.Set Properties Preserved Batch	✅	8ms
Event Format.Set Once Properties Preserved Batch	✅	9ms
Event Format.Groups Properties Preserved Batch	✅	8ms
Event Format.Sdk Generates Uuid If Not Provided Batch	✅	8ms
Batch Behavior.Multiple Events In Single Batch	✅	31ms
Batch Behavior.Batch Envelope Smoke	✅	10ms
Batch Behavior.Flush With No Events Sends Nothing	✅	3ms
Batch Behavior.Flush At Triggers Batch	✅	1007ms
Batch Behavior.Created At Reflects Batch Creation Time	✅	7ms
Deduplication.Generates Unique Uuids	✅	15ms
Deduplication.Different Events Same Content Different Uuids	✅	7ms
Deduplication.Preserves Uuid On Retry	✅	5135ms
Deduplication.Preserves Timestamp On Retry	✅	5136ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	5133ms
Deduplication.No Duplicate Events In Batch	✅	31ms
Header Behavior On Retry.Attempt Header Starts At One	✅	6ms
Header Behavior On Retry.Attempt Header Increments On Retry	✅	10139ms
Header Behavior On Retry.Request Id Preserved On Retry	✅	5136ms
Header Behavior On Retry.Different Requests Have Different Request Ids	✅	2014ms
Header Behavior On Retry.Request Timestamp Changes On Retry	✅	5134ms
Response Format Validation.Success Response Has Uuid Keyed Results	✅	7ms
Response Format Validation.Success Response Has Ok For Each Event	✅	28ms
Response Format Validation.Success No Retry After When All Ok	✅	27ms
Response Format Validation.Success Retry After Present When Retry Events	✅	129ms
Response Format Validation.Success No Retry After When Drop Only	✅	28ms
Response Format Validation.Response Echoes Request Id	✅	6ms
Retry Behavior.Retries On 408	✅	5134ms
Retry Behavior.Retries On 500	✅	5136ms
Retry Behavior.Retries On 503	✅	5135ms
Retry Behavior.Retries On 504	✅	5135ms
Retry Behavior.Retryable Errors Have Retry After	✅	2134ms
Retry Behavior.Respects Retry After On Retryable Error	✅	8133ms
Retry Behavior.Does Not Retry On 400	✅	2133ms
Retry Behavior.Does Not Retry On 401	✅	2132ms
Retry Behavior.Does Not Retry On 402	✅	2133ms
Retry Behavior.Does Not Retry On 413	✅	2132ms
Retry Behavior.Does Not Retry On 415	✅	2133ms
Retry Behavior.Non Retryable Errors Have No Retry After	✅	2133ms
Retry Behavior.Implements Backoff	✅	15142ms
Retry Behavior.Max Retries Respected	✅	15143ms
Partial Batch Handling.Handles 200 Full Success	✅	2009ms
Partial Batch Handling.Handles 200 With All Ok	✅	3031ms
Partial Batch Handling.Does Not Retry Dropped Events	✅	3030ms
Partial Batch Handling.Does Not Retry Limited Events	✅	3032ms
Partial Batch Handling.Prunes Ok Events On Partial Retry	✅	5135ms
Partial Batch Handling.Prunes Dropped Events On Partial Retry	✅	5136ms
Partial Batch Handling.Retries Only Retry Events From Partial	✅	5137ms
Partial Batch Handling.Partial Retry Preserves Uuids	✅	5137ms
Partial Batch Handling.Partial Retry Attempt Header Increments	✅	5136ms
Partial Batch Handling.Partial Retry Request Id Preserved	✅	5135ms
Partial Batch Handling.Respects Retry After On Partial	✅	5136ms
Partial Batch Handling.Unknown Result Treated As Terminal	✅	3031ms
Partial Batch Handling.Mixed Ok Drop Limited No Retry	✅	3033ms
Compression.Sends Gzip Content Encoding	✅	7ms
Compression.No Content Encoding When Disabled	✅	6ms
Compression.Compressed Body Is Decompressible	✅	6ms
Error Handling.Does Not Retry On Unknown 4Xx	✅	2131ms
Event Options.Cookieless Mode Override	✅	7ms
Event Options.Disable Skew Correction Override	✅	6ms
Event Options.Process Person Profile Override	✅	5ms
Event Options.Product Tour Id Override	✅	6ms
Event Options.Unset Options Omitted	✅	5ms
Event Options.Options Override In Batch	✅	9ms
Geoip And Historical Migration.Geoip Disable Injected Into Properties	✅	6ms
Geoip And Historical Migration.Historical Migration Set In Body	✅	6ms
Geoip And Historical Migration.Historical Migration Absent By Default	✅	6ms

Feature_Flags Tests

⚠️ 15/17 tests passed, 2 failed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	15ms
Request Payload.Flags Request Uses V2 Query Param	✅	16ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	15ms
Request Payload.Flags Request Omits Authorization Header	✅	15ms
Request Payload.Token In Flags Body Matches Init	✅	16ms
Request Payload.Groups Round Trip	✅	16ms
Request Payload.Groups Default To Empty Object	✅	15ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	15ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	16ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	16ms
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	✅	29ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	16ms
Retry Behavior.Retries Flags On 502	❌	5ms
Retry Behavior.Retries Flags On 504	❌	5ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	17ms

Failures

retry_behavior.retries_flags_on_502

500, message='Internal Server Error', url='http://sdk-adapter:8080/get_feature_flag'

retry_behavior.retries_flags_on_504

500, message='Internal Server Error', url='http://sdk-adapter:8080/get_feature_flag'

[greptile-apps]

_{Reviews (1): Last reviewed commit: "feat: send error tracking stack frames i..." | Re-trigger Greptile}

[github-actions]

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