PostHog/posthog

Bug: In Cohorts, the 'set' operator filters in null values for person properties

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#29,916 opened on 2025年3月13日

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説明

Bug description

In Cohorts, 'set' operator filters in null values for person properties.

Expected outcome

  • 'set' should filter out null values
  • 'not set' should include null values

Using Have the property vs Does not have the property doesn't solve this because we want to filter out users who have the property but with a null value.

In filters, 'not set' filters in 'null while 'set' filters it out. This means there's an inconsistency with how we handle this in Cohorts.

How to reproduce

  1. Create a cohort and filter by having a person property that you know some users have null for and select 'set'
  2. notice the list of users includes users with 'null'

You can test with this cohort: https://us.posthog.com/project/53137/cohorts/122367

Additional context

From: https://posthoghelp.zendesk.com/agent/tickets/27021

Debug info

null

コントリビューターガイド

技術スタック
python
領域
backend
Issue 種別
bug
難度新しい貢献者にとっての実装難度です。1 は非常に小さな変更、5 は専門的な作業です。
3
推定時間経験ある貢献者が調査、実装、テスト、pull request 準備にかけるおおよその時間範囲です。
1-3 hours
活動状況Issue が今どれだけ取り組みやすいかを示します。新しい、活発、古い、ブロック中、またはメンテナー入力待ちなどです。
active
明確さ期待される変更、受け入れ条件、次の手順がどれだけ明確かを示します。
clear
前提条件
Understanding of cohort filteringSQL null handling knowledgeFamiliarity with PostHog property filters
初心者向け度初回貢献者にどれだけ取り組みやすいかを 1-100 で推定したスコアです。
50
調査方針
Investigate the cohort filtering logic in the backend, specifically the handling of null values for person properties. Look at the query building code for cohort definitions, likely in the `posthog/models/cohort` or `posthog/queries` directory. Compare the `set` and `not set` operators' behavior with person property filters. Ensure that the SQL query for 'set' excludes null values and 'not set' includes them. Refer to the existing filter logic in `PropertyFilter` classes.