From 0492a6597feae153b50ae6488888b0de2473ab0c Mon Sep 17 00:00:00 2001
From: Ayush Jhanwar <ayush.jhanwar@dashverse.ai>
Date: Wed, 2 Sep 2026 13:29:06 +0530
Subject: [PATCH] fix(track): don't drop increment/decrement for a
 not-yet-created profile

adjustProfileProperty threw HttpError 404 ('Profile not found') when
getProfileById returned nothing, and 400 when the existing value wasn't
numeric. Both cases silently drop the operation.

A missing profile is not an error condition here: an increment/decrement
routinely fires before the profile's first event or identify has landed
(a race), or for an anonymous/transient id. Rejecting it loses the delta
and never creates the counter.

Adopt Mixpanel $add / $subtract semantics: treat the current value as 0,
upsert (creating the profile if needed), and apply the delta. A
non-numeric existing value is skipped rather than 400'd, and is never
overwritten with NaN. Existing numeric profiles are unaffected.
---
 apps/api/src/controllers/track.controller.ts | 30 +++++++++++---------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/apps/api/src/controllers/track.controller.ts b/apps/api/src/controllers/track.controller.ts
index 3452de4f8..55efe6bae 100644
--- a/apps/api/src/controllers/track.controller.ts
+++ b/apps/api/src/controllers/track.controller.ts
@@ -321,29 +321,33 @@ async function adjustProfileProperty(
 ): Promise<void> {
   const { profileId, property, value } = payload;
   const profile = await getProfileById(String(profileId), projectId);
-  if (!profile) {
-    throw new HttpError('Profile not found', { status: 404 });
-  }
+
+  // A missing profile is not an error. An increment/decrement legitimately
+  // fires before the profile's first event or identify has landed (a common
+  // race), or for an anonymous/transient id. Follow Mixpanel `$add`/`$subtract`
+  // semantics — treat the current value as 0 and upsert — so the delta is
+  // preserved and the profile is created, instead of dropping the operation.
+  const properties = profile?.properties ?? {};
 
   const parsed = Number.parseInt(
-    pathOr<string>('0', property.split('.'), profile.properties),
+    pathOr<string>('0', property.split('.'), properties),
     10
   );
 
+  // An existing value that isn't a number can't be adjusted; skip rather than
+  // rejecting the request (and never overwrite it with a NaN).
   if (Number.isNaN(parsed)) {
-    throw new HttpError('Property value is not a number', { status: 400 });
+    return;
   }
 
-  profile.properties = assocPath(
-    property.split('.'),
-    parsed + direction * (value || 1),
-    profile.properties
-  );
-
   await upsertProfile({
-    id: profile.id,
+    id: profile?.id ?? String(profileId),
     projectId,
-    properties: profile.properties,
+    properties: assocPath(
+      property.split('.'),
+      parsed + direction * (value || 1),
+      properties
+    ),
     isExternal: true,
   });
 }