fix(node): captureException uses distinctId from request context

.changeset/warm-foxes-glow.md

@@ -0,0 +1,5 @@
+---
+'posthog-node': patch
+---
+
+fix: captureException now uses distinctId from request context

packages/node/src/__tests__/context.spec.ts

@@ -459,4 +459,42 @@ describe('PostHog Context', () => {
       expect(body.distinct_id).toBe('explicit-user')
     })
   })
+
+  it.each([
+    {
+      label: 'no distinctId and no context → personless',
+      contextDistinctId: undefined,
+      explicitDistinctId: undefined,
+      expectedDistinctId: (id: string) => expect(typeof id).toBe('string'),
+      expectedProcessPersonProfile: false,
+    },
+    {
+      label: 'context distinctId only → uses context',
+      contextDistinctId: 'context-user',
+      explicitDistinctId: undefined,
+      expectedDistinctId: (id: string) => expect(id).toBe('context-user'),
+      expectedProcessPersonProfile: undefined,
+    },
+    {
+      label: 'explicit distinctId overrides context',
+      contextDistinctId: 'context-user',
+      explicitDistinctId: 'explicit-user',
+      expectedDistinctId: (id: string) => expect(id).toBe('explicit-user'),
+      expectedProcessPersonProfile: undefined,
+    },
+  ])(
+    'captureException $label',
+    async ({ contextDistinctId, explicitDistinctId, expectedDistinctId, expectedProcessPersonProfile }) => {
+      const run = () => posthog.captureException(new Error('test error'), explicitDistinctId)
+      contextDistinctId ? posthog.withContext({ distinctId: contextDistinctId }, run) : run()
+
+      await waitForFlush()
+
+      const events = getLastBatchEvents()
+      expect(events).toHaveLength(1)
+      expect(events?.[0].event).toBe('$exception')
+      expectedDistinctId(events?.[0].distinct_id)
+      expect(events?.[0].properties.$process_person_profile).toBe(expectedProcessPersonProfile)
+    }
+  )
 })

packages/node/src/extensions/error-tracking/index.ts

@@ -1,6 +1,6 @@
 import { addUncaughtExceptionListener, addUnhandledRejectionListener } from './autocapture'
 import { PostHogBackendClient } from '@/client'
-import { isObject, uuidv7 } from '@posthog/core'
+import { isObject } from '@posthog/core'
 import { EventMessage, PostHogOptions } from '@/types'
 import type { Logger } from '@posthog/core'
 import { BucketedRateLimiter } from '@posthog/core'
@@ -46,20 +46,16 @@ export default class ErrorTracking {
   ): Promise<EventMessage> {
     const properties: EventMessage['properties'] = { ...additionalProperties }
 
-    // Given stateless nature of Node SDK we capture exceptions using personless processing when no
-    // user can be determined because a distinct_id is not provided e.g. exception autocapture
-    if (!distinctId) {
-      properties.$process_person_profile = false
-    }
-
     const exceptionProperties = this.errorPropertiesBuilder.buildFromUnknown(error, hint)
     exceptionProperties.$exception_list = await this.errorPropertiesBuilder.modifyFrames(
       exceptionProperties.$exception_list
     )
 
     return {
       event: '$exception',
-      distinctId: distinctId || uuidv7(),
+      // Leave distinctId resolution to prepareEventMessage which checks request context
+      // and falls back to a random UUID with $process_person_profile = false
+      distinctId: distinctId,
       properties: {
         ...exceptionProperties,
         ...properties,