From 26ea95f7281d5971dea895cc553aecc02a5e73a6 Mon Sep 17 00:00:00 2001
From: Brett Hoerner <brett@posthog.com>
Date: Tue, 2 Jul 2024 14:29:23 -0600
Subject: [PATCH] feat(plugin-server): only write personless overrides when
 necessary (#23407)

---
 plugin-server/src/worker/ingestion/person-state.ts |  6 +++---
 .../tests/worker/ingestion/person-state.test.ts    | 14 ++------------
 2 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/plugin-server/src/worker/ingestion/person-state.ts b/plugin-server/src/worker/ingestion/person-state.ts
index 3475bc669528a..6e0ac0202fa7f 100644
--- a/plugin-server/src/worker/ingestion/person-state.ts
+++ b/plugin-server/src/worker/ingestion/person-state.ts
@@ -529,12 +529,12 @@ export class PersonState {
                 'mergeDistinctIds-OneExists',
                 async (tx) => {
                     // See comment above about `distinctIdVersion`
-                    const _insertedDistinctId = await this.db.addPersonlessDistinctIdForMerge(
+                    const insertedDistinctId = await this.db.addPersonlessDistinctIdForMerge(
                         this.teamId,
                         distinctIdToAdd,
                         tx
                     )
-                    const distinctIdVersion = 1 // TODO: Once `posthog_personlessdistinctid` is backfilled: insertedDistinctId ? 0 : 1
+                    const distinctIdVersion = insertedDistinctId ? 0 : 1
 
                     await this.db.addDistinctId(existingPerson, distinctIdToAdd, distinctIdVersion, tx)
                     return [existingPerson, Promise.resolve()]
@@ -584,7 +584,7 @@ export class PersonState {
                     // whether we can optimize away an override by doing a swap, or whether we
                     // need to actually write an override. (But mostly we're being verbose for
                     // documentation purposes)
-                    let distinctId2Version = 1 // TODO: Once `posthog_personlessdistinctid` is backfilled, this should be = 0
+                    let distinctId2Version = 0
                     if (insertedDistinctId1 && insertedDistinctId2) {
                         // We were the first to insert both (neither was used for Personless), so we
                         // can use either as the primary Person UUID and create no overrides.
diff --git a/plugin-server/tests/worker/ingestion/person-state.test.ts b/plugin-server/tests/worker/ingestion/person-state.test.ts
index 06bd8086ead84..f8220ba9ba155 100644
--- a/plugin-server/tests/worker/ingestion/person-state.test.ts
+++ b/plugin-server/tests/worker/ingestion/person-state.test.ts
@@ -278,19 +278,9 @@ describe('PersonState.update()', () => {
                 ])
             )
 
-            // old2 does have an override, because we are temporarily writing out unnecessary
-            // overrides while we backfill `posthog_personlessdistinctid`
+            // old2 has no override, because it wasn't in posthog_personlessdistinctid
             const chOverridesOld = await fetchOverridesForDistinctId('old2')
-            expect(chOverridesOld.length).toEqual(1)
-            expect(chOverridesOld).toEqual(
-                expect.arrayContaining([
-                    expect.objectContaining({
-                        distinct_id: 'old2',
-                        person_id: oldUserUuid,
-                        version: 1,
-                    }),
-                ])
-            )
+            expect(chOverridesOld.length).toEqual(0)
         })
 
         it('force_upgrade works', async () => {