feat(error-tracking): standardize exception event metadata

[hpouillot]

💡 Motivation and Context

Standardize Rust exception events across manual error capture, error source chains, and panic hooks with the cross-SDK metadata contract.

Canonical contract: https://github.com/PostHog/sdk-specs/blob/main/openspec/specs/exception-event-metadata/spec.md

💚 How did you test it?

• Focused error-tracking tests
• cargo fmt --check

Strict Clippy remains blocked by existing deprecated test APIs and a duplicate attribute outside this change.

📝 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 pi from the shared OpenSpec contract. Error source traversal is deterministic, cycle-safe, bounded, and records canonical relationship metadata.

[github-actions]

posthog-rs-v0 Compliance Report

Date: 2026-08-26 08:26:43 UTC
Duration: 15571ms

✅ All Tests Passed!

46/46 tests passed

---

Capture Tests

✅ 29/29 tests passed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	161ms
Format Validation.Event Has Uuid	✅	168ms
Format Validation.Event Has Lib Properties	✅	160ms
Format Validation.Distinct Id Is String	✅	159ms
Format Validation.Token Is Present	✅	160ms
Format Validation.Custom Properties Preserved	✅	167ms
Format Validation.Event Has Timestamp	✅	160ms
Retry Behavior.Retries On 503	✅	5168ms
Retry Behavior.Does Not Retry On 400	✅	2167ms
Retry Behavior.Does Not Retry On 401	✅	2167ms
Retry Behavior.Respects Retry After Header	✅	5098ms
Retry Behavior.Implements Backoff	✅	15105ms
Retry Behavior.Retries On 500	✅	5096ms
Retry Behavior.Retries On 502	✅	5097ms
Retry Behavior.Retries On 504	✅	5096ms
Retry Behavior.Max Retries Respected	✅	15098ms
Deduplication.Generates Unique Uuids	✅	97ms
Deduplication.Preserves Uuid On Retry	✅	5024ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	10034ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	5041ms
Deduplication.No Duplicate Events In Batch	✅	27ms
Deduplication.Different Events Have Different Uuids	✅	23ms
Compression.Sends Gzip When Enabled	✅	22ms
Batch Format.Uses Proper Batch Structure	✅	27ms
Batch Format.Flush With No Events Sends Nothing	✅	59ms
Batch Format.Multiple Events Batched Together	✅	130ms
Error Handling.Does Not Retry On 403	✅	2082ms
Error Handling.Does Not Retry On 413	✅	2068ms
Error Handling.Retries On 408	✅	5088ms

Feature_Flags Tests

✅ 17/17 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	49ms
Request Payload.Flags Request Uses V2 Query Param	✅	39ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	32ms
Request Payload.Flags Request Omits Authorization Header	✅	30ms
Request Payload.Token In Flags Body Matches Init	✅	55ms
Request Payload.Groups Round Trip	✅	44ms
Request Payload.Groups Default To Empty Object	✅	41ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	42ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	39ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	39ms
Request Lifecycle.No Flags Request On Init Alone	✅	15ms
Request Lifecycle.No Flags Request On Normal Capture	✅	51ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	54ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	36ms
Retry Behavior.Retries Flags On 502	✅	245ms
Retry Behavior.Retries Flags On 504	✅	245ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	46ms

[github-actions]

posthog-rs-v1 Compliance Report

Date: 2026-08-26 08:27:23 UTC
Duration: 22809ms

✅ All Tests Passed!

111/111 tests passed

---

Capture_V1 Tests

✅ 94/94 tests passed

View Details

Test	Status	Duration
Endpoint And Method.Targets V1 Endpoint	✅	105ms
Endpoint And Method.Does Not Use Legacy Endpoints	✅	105ms
Required Headers.Has Authorization Bearer Header	✅	105ms
Required Headers.Has Content Type Json	✅	104ms
Required Headers.Has Posthog Sdk Info Format	✅	105ms
Required Headers.Has Posthog Attempt Header	✅	103ms
Required Headers.Has Posthog Request Id	✅	105ms
Required Headers.Has Posthog Request Timestamp	✅	103ms
Required Headers.Has User Agent	✅	107ms
Body Format.Body Has Created At And Batch	✅	102ms
Body Format.No Api Key In Body	✅	100ms
Body Format.No Sent At In Body	✅	100ms
Event Format.Event Has Required Root Fields	✅	100ms
Event Format.Event Uuid Is Valid	✅	101ms
Event Format.Event Timestamp Is Rfc3339	✅	100ms
Event Format.Distinct Id Is String	✅	101ms
Event Format.Distinct Id At Root Not Properties	✅	101ms
Event Format.Custom Properties Preserved	✅	100ms
Event Format.Set Properties Preserved	✅	100ms
Event Format.Set Once Properties Preserved	✅	102ms
Event Format.Groups Properties Preserved	✅	88ms
Event Format.Sdk Generates Uuid If Not Provided	✅	87ms
Event Format.Event Has Required Root Fields Batch	✅	110ms
Event Format.Event Uuid Is Valid Batch	✅	109ms
Event Format.Event Timestamp Is Rfc3339 Batch	✅	127ms
Event Format.Distinct Id Is String Batch	✅	126ms
Event Format.Distinct Id At Root Not Properties Batch	✅	115ms
Event Format.Custom Properties Preserved Batch	✅	115ms
Event Format.Set Properties Preserved Batch	✅	126ms
Event Format.Set Once Properties Preserved Batch	✅	122ms
Event Format.Groups Properties Preserved Batch	✅	116ms
Event Format.Sdk Generates Uuid If Not Provided Batch	✅	123ms
Batch Behavior.Multiple Events In Single Batch	✅	142ms
Batch Behavior.Batch Envelope Smoke	✅	143ms
Batch Behavior.Flush With No Events Sends Nothing	✅	64ms
Batch Behavior.Flush At Triggers Batch	✅	1098ms
Batch Behavior.Created At Reflects Batch Creation Time	✅	95ms
Deduplication.Generates Unique Uuids	✅	164ms
Deduplication.Different Events Same Content Different Uuids	✅	94ms
Deduplication.Preserves Uuid On Retry	✅	5098ms
Deduplication.Preserves Timestamp On Retry	✅	5075ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	5091ms
Deduplication.No Duplicate Events In Batch	✅	92ms
Header Behavior On Retry.Attempt Header Starts At One	✅	57ms
Header Behavior On Retry.Attempt Header Increments On Retry	✅	10070ms
Header Behavior On Retry.Request Id Preserved On Retry	✅	5052ms
Header Behavior On Retry.Different Requests Have Different Request Ids	✅	2053ms
Header Behavior On Retry.Request Timestamp Changes On Retry	✅	5038ms
Response Format Validation.Success Response Has Uuid Keyed Results	✅	27ms
Response Format Validation.Success Response Has Ok For Each Event	✅	31ms
Response Format Validation.Success No Retry After When All Ok	✅	17ms
Response Format Validation.Success Retry After Present When Retry Events	✅	21ms
Response Format Validation.Success No Retry After When Drop Only	✅	22ms
Response Format Validation.Response Echoes Request Id	✅	17ms
Retry Behavior.Retries On 408	✅	5022ms
Retry Behavior.Retries On 500	✅	5018ms
Retry Behavior.Retries On 503	✅	5020ms
Retry Behavior.Retries On 504	✅	5019ms
Retry Behavior.Retryable Errors Have Retry After	✅	2020ms
Retry Behavior.Respects Retry After On Retryable Error	✅	8017ms
Retry Behavior.Does Not Retry On 400	✅	2022ms
Retry Behavior.Does Not Retry On 401	✅	2022ms
Retry Behavior.Does Not Retry On 402	✅	2018ms
Retry Behavior.Does Not Retry On 413	✅	2024ms
Retry Behavior.Does Not Retry On 415	✅	2020ms
Retry Behavior.Non Retryable Errors Have No Retry After	✅	2022ms
Retry Behavior.Implements Backoff	✅	15025ms
Retry Behavior.Max Retries Respected	✅	15024ms
Partial Batch Handling.Handles 200 Full Success	✅	2023ms
Partial Batch Handling.Handles 200 With All Ok	✅	3034ms
Partial Batch Handling.Does Not Retry Dropped Events	✅	3027ms
Partial Batch Handling.Does Not Retry Limited Events	✅	3023ms
Partial Batch Handling.Prunes Ok Events On Partial Retry	✅	5025ms
Partial Batch Handling.Prunes Dropped Events On Partial Retry	✅	5019ms
Partial Batch Handling.Retries Only Retry Events From Partial	✅	5019ms
Partial Batch Handling.Partial Retry Preserves Uuids	✅	5020ms
Partial Batch Handling.Partial Retry Attempt Header Increments	✅	5028ms
Partial Batch Handling.Partial Retry Request Id Preserved	✅	5028ms
Partial Batch Handling.Respects Retry After On Partial	✅	5019ms
Partial Batch Handling.Unknown Result Treated As Terminal	✅	3019ms
Partial Batch Handling.Mixed Ok Drop Limited No Retry	✅	3028ms
Compression.Sends Gzip Content Encoding	✅	25ms
Compression.No Content Encoding When Disabled	✅	15ms
Compression.Compressed Body Is Decompressible	✅	16ms
Error Handling.Does Not Retry On Unknown 4Xx	✅	2017ms
Event Options.Cookieless Mode Override	✅	19ms
Event Options.Disable Skew Correction Override	✅	16ms
Event Options.Process Person Profile Override	✅	16ms
Event Options.Product Tour Id Override	✅	15ms
Event Options.Unset Options Omitted	✅	16ms
Event Options.Options Override In Batch	✅	16ms
Geoip And Historical Migration.Geoip Disable Injected Into Properties	✅	16ms
Geoip And Historical Migration.Historical Migration Set In Body	✅	16ms
Geoip And Historical Migration.Historical Migration Absent By Default	✅	17ms

Feature_Flags Tests

✅ 17/17 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	11ms
Request Payload.Flags Request Uses V2 Query Param	✅	11ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	10ms
Request Payload.Flags Request Omits Authorization Header	✅	12ms
Request Payload.Token In Flags Body Matches Init	✅	12ms
Request Payload.Groups Round Trip	✅	11ms
Request Payload.Groups Default To Empty Object	✅	11ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	12ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	13ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	10ms
Request Lifecycle.No Flags Request On Init Alone	✅	8ms
Request Lifecycle.No Flags Request On Normal Capture	✅	15ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	13ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	10ms
Retry Behavior.Retries Flags On 502	✅	215ms
Retry Behavior.Retries Flags On 504	✅	217ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	17ms

[github-actions]

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