feat: swap the default to identified_only

src/__tests__/personProcessing.test.ts

@@ -44,18 +44,23 @@ describe('person processing', () => {
         mockURLGetter.mockReturnValue('https://example.com?utm_source=foo')
     })
 
-    const setup = async (person_profiles: 'always' | 'identified_only' | 'never' | undefined, token?: string) => {
+    const setup = async (
+        person_profiles: 'always' | 'identified_only' | 'never' | undefined,
+        token?: string,
+        persistence_name?: string
+    ) => {
         token = token || uuidv7()
         const onCapture = jest.fn()
         const posthog = await createPosthogInstance(token, {
             _onCapture: onCapture,
             person_profiles,
+            persistence_name,
         })
         return { token, onCapture, posthog }
     }
 
     describe('init', () => {
-        it("should default to 'always' person_profiles", async () => {
+        it("should default to 'identified_only' person_profiles", async () => {
             // arrange
             const token = uuidv7()
 
@@ -65,7 +70,7 @@ describe('person processing', () => {
             })
 
             // assert
-            expect(posthog.config.person_profiles).toEqual('always')
+            expect(posthog.config.person_profiles).toEqual('identified_only')
         })
         it('should read person_profiles from init config', async () => {
             // arrange
@@ -547,4 +552,48 @@ describe('person processing', () => {
             expect(onCapture.mock.calls[2][1].properties.$process_person_profile).toEqual(false)
         })
     })
+
+    describe('persistence', () => {
+        it('should remember that a user set the mode to always on a previous visit', async () => {
+            // arrange
+            const persistenceName = uuidv7()
+            const { posthog: posthog1, onCapture: onCapture1 } = await setup('always', undefined, persistenceName)
+            posthog1.capture('custom event 1')
+            const { posthog: posthog2, onCapture: onCapture2 } = await setup(
+                'identified_only',
+                undefined,
+                persistenceName
+            )
+
+            // act
+            posthog2.capture('custom event 2')
+
+            // assert
+            expect(onCapture1.mock.calls.length).toEqual(1)
+            expect(onCapture2.mock.calls.length).toEqual(1)
+            expect(onCapture1.mock.calls[0][1].properties.$process_person_profile).toEqual(true)
+            expect(onCapture2.mock.calls[0][1].properties.$process_person_profile).toEqual(true)
+        })
+
+        it('should work when always is set on a later visit', async () => {
+            // arrange
+            const persistenceName = uuidv7()
+            const { posthog: posthog1, onCapture: onCapture1 } = await setup(
+                'identified_only',
+                undefined,
+                persistenceName
+            )
+            posthog1.capture('custom event 1')
+            const { posthog: posthog2, onCapture: onCapture2 } = await setup('always', undefined, persistenceName)
+
+            // act
+            posthog2.capture('custom event 2')
+
+            // assert
+            expect(onCapture1.mock.calls.length).toEqual(1)
+            expect(onCapture2.mock.calls.length).toEqual(1)
+            expect(onCapture1.mock.calls[0][1].properties.$process_person_profile).toEqual(false)
+            expect(onCapture2.mock.calls[0][1].properties.$process_person_profile).toEqual(true)
+        })
+    })
 })

src/__tests__/posthog-core.test.ts

@@ -115,6 +115,7 @@ describe('posthog core', () => {
                 const { posthog, onCapture } = setup({
                     token,
                     persistence_name: token,
+                    person_profiles: 'always',
                 })
 
                 // act
@@ -135,6 +136,7 @@ describe('posthog core', () => {
                 const { posthog: posthog1 } = setup({
                     token,
                     persistence_name: token,
+                    person_profiles: 'always',
                 })
                 posthog1.capture(eventName, eventProperties)
                 mockReferrerGetter.mockReturnValue('https://referrer2.example.com/some/path')
@@ -165,6 +167,7 @@ describe('posthog core', () => {
                 const { posthog: posthog1 } = setup({
                     token,
                     persistence_name: token,
+                    person_profiles: 'always',
                 })
                 posthog1.capture(eventName, eventProperties)
                 mockReferrerGetter.mockReturnValue('https://referrer2.example.com/some/path')
@@ -195,6 +198,7 @@ describe('posthog core', () => {
                 const { posthog, onCapture } = setup({
                     token,
                     persistence_name: token,
+                    person_profiles: 'always',
                 })
 
                 // act

src/__tests__/posthog-core.ts

@@ -4,7 +4,7 @@ import { Info } from '../utils/event-utils'
 import { document, window } from '../utils/globals'
 import { uuidv7 } from '../uuidv7'
 import * as globals from '../utils/globals'
-import { USER_STATE } from '../constants'
+import { ENABLE_PERSON_PROCESSING, USER_STATE } from '../constants'
 import { createPosthogInstance, defaultPostHog } from './helpers/posthog-instance'
 import { logger } from '../utils/logger'
 import { DecideResponse, PostHogConfig } from '../types'
@@ -345,6 +345,20 @@ describe('posthog core', () => {
 
             expect(posthog.compression).toEqual('gzip-js')
         })
+        it('uses defaultIdentifiedOnly from decide response', () => {
+            const posthog = posthogWith({})
+
+            posthog._afterDecideResponse({ defaultIdentifiedOnly: true } as DecideResponse)
+            expect(posthog.config.person_profiles).toEqual('identified_only')
+
+            posthog._afterDecideResponse({ defaultIdentifiedOnly: false } as DecideResponse)
+            expect(posthog.config.person_profiles).toEqual('always')
+        })
+        it('defaultIdentifiedOnly does not override person_profiles if already set', () => {
+            const posthog = posthogWith({ person_profiles: 'always' })
+            posthog._afterDecideResponse({ defaultIdentifiedOnly: true } as DecideResponse)
+            expect(posthog.config.person_profiles).toEqual('always')
+        })
 
         it('enables compression from decide response when only one received', () => {
             const posthog = posthogWith({})
@@ -387,6 +401,8 @@ describe('posthog core', () => {
                 properties: () => ({ distinct_id: 'abc', persistent: 'prop', $is_identified: false }),
                 remove_event_timer: jest.fn(),
                 get_property: () => 'anonymous',
+                props: {},
+                register: jest.fn(),
             } as unknown as PostHogPersistence,
             sessionPersistence: {
                 properties: () => ({ distinct_id: 'abc', persistent: 'prop' }),
@@ -425,7 +441,7 @@ describe('posthog core', () => {
                 $window_id: 'windowId',
                 $session_id: 'sessionId',
                 $is_identified: false,
-                $process_person_profile: true,
+                $process_person_profile: false,
             })
         })
 
@@ -447,7 +463,7 @@ describe('posthog core', () => {
                 $session_id: 'sessionId',
                 $lib_custom_api_host: 'https://custom.posthog.com',
                 $is_identified: false,
-                $process_person_profile: true,
+                $process_person_profile: false,
             })
         })
 
@@ -465,7 +481,7 @@ describe('posthog core', () => {
                 posthog._calculate_event_properties('custom_event', { event: 'prop' }, new Date())[
                     '$process_person_profile'
                 ]
-            ).toEqual(true)
+            ).toEqual(false)
         })
 
         it('only adds token and distinct_id if event_name is $snapshot', () => {
@@ -496,7 +512,7 @@ describe('posthog core', () => {
             expect(posthog._calculate_event_properties('custom_event', { event: 'prop' }, new Date())).toEqual({
                 event_name: 'custom_event',
                 token: 'testtoken',
-                $process_person_profile: true,
+                $process_person_profile: false,
             })
         })
 
@@ -510,6 +526,7 @@ describe('posthog core', () => {
             )
 
             posthog.persistence.get_initial_props = () => ({ initial: 'prop' })
+            posthog.persistence.props[ENABLE_PERSON_PROCESSING] = true // person processing is needed for $set_once
             expect(posthog._calculate_set_once_properties({ key: 'prop' })).toEqual({
                 event_name: '$set_once',
                 token: undefined,

src/posthog-core.ts

@@ -179,7 +179,7 @@ export const defaultConfig = (): PostHogConfig => ({
     bootstrap: {},
     disable_compression: false,
     session_idle_timeout_seconds: 30 * 60, // 30 minutes
-    person_profiles: 'always',
+    person_profiles: 'identified_only',
     __add_tracing_headers: false,
 })
 
@@ -272,6 +272,7 @@ export class PostHog {
     decideEndpointWasHit: boolean
     analyticsDefaultEndpoint: string
     version = Config.LIB_VERSION
+    _initialPersonProfilesConfig: 'always' | 'never' | 'identified_only' | null
 
     SentryIntegration: typeof SentryIntegration
     sentryIntegration: (options?: SentryIntegrationOptions) => ReturnType<typeof sentryIntegration>
@@ -294,6 +295,7 @@ export class PostHog {
         this.__loaded = false
         this.analyticsDefaultEndpoint = '/e/'
         this._initialPageviewCaptured = false
+        this._initialPersonProfilesConfig = null
 
         this.featureFlags = new PostHogFeatureFlags(this)
         this.toolbar = new Toolbar(this)
@@ -390,6 +392,10 @@ export class PostHog {
         this.config = {} as PostHogConfig // will be set right below
         this._triggered_notifs = []
 
+        if (config.person_profiles) {
+            this._initialPersonProfilesConfig = config.person_profiles
+        }
+
         this.set_config(
             extend({}, defaultConfig(), configRenames(config), {
                 name: name,
@@ -408,6 +414,8 @@ export class PostHog {
             this.config.persistence === 'sessionStorage'
                 ? this.persistence
                 : new PostHogPersistence({ ...this.config, persistence: 'sessionStorage' })
+
+        // should I store the initial person profiles config in persistence?
         const initialPersistenceProps = { ...this.persistence.props }
         const initialSessionProps = { ...this.sessionPersistence.props }
 
@@ -538,6 +546,12 @@ export class PostHog {
             this.analyticsDefaultEndpoint = response.analytics.endpoint
         }
 
+        this.config.person_profiles = this._initialPersonProfilesConfig
+            ? this._initialPersonProfilesConfig
+            : response['defaultIdentifiedOnly']
+            ? 'identified_only'
+            : 'always'
+
         this.sessionRecording?.afterDecideResponse(response)
         this.autocapture?.afterDecideResponse(response)
         this.heatmaps?.afterDecideResponse(response)
@@ -977,8 +991,13 @@ export class PostHog {
             properties = sanitize_properties(properties, event_name)
         }
 
-        // add person processing flag as very last step, so it cannot be overridden. process_person=true is default
-        properties['$process_person_profile'] = this._hasPersonProcessing()
+        // add person processing flag as very last step, so it cannot be overridden
+        const hasPersonProcessing = this._hasPersonProcessing()
+        properties['$process_person_profile'] = hasPersonProcessing
+        // if the event has person processing, ensure that all future events will too, even if the setting changes
+        if (hasPersonProcessing) {
+            this._requirePersonProcessing('_calculate_event_properties')
+        }
 
         return properties
     }

src/types.ts

@@ -398,6 +398,7 @@ export interface DecideResponse {
     isAuthenticated: boolean
     siteApps: { id: number; url: string }[]
     heatmaps?: boolean
+    defaultIdentifiedOnly?: boolean
 }
 
 export type FeatureFlagsCallback = (