[an8kk]

Treat explicit JSON/null property values as unset for cohort and person-property matching.

Previously, set filters could match properties whose key existed but whose value was JSON null. This makes set require a non-null value and makes not set include missing or null values across ClickHouse SQL, Django query construction, override matching, and the Rust cohort/feature-flag matcher.

ClickHouse materialized-property filters now check the raw JSON value for null semantics, keeping the literal string "null" distinct from JSON null.

Verified with focused Python property-filter tests and targeted Rust matcher tests.

Fixes #29916

[greptile-apps]

Comments Outside Diff (2)

1. posthog/queries/base.py, line 83-84 (link)

   The docstring comment on line 84 is now inaccurate. is_not_set is supported by this PR when the key exists in override_property_values with a None value.

   Prompt To Fix With AI

   This is a comment left during a code review.
   Path: posthog/queries/base.py
   Line: 83-84
   
   Comment:
   The docstring comment on line 84 is now inaccurate. `is_not_set` is supported by this PR when the key exists in `override_property_values` with a `None` value.
   
   
   
   How can I resolve this? If you propose a fix, please make it concise.

2. ee/clickhouse/models/test/test_property.py, line 1856-1893 (link)

   Non-parameterised test for the materialized case

   The codebase convention is to prefer parameterised tests. test_prop_filter_json_extract_set_operators_use_raw_json_when_materialized tests is_set and is_not_set as separate assertions inside one test body. These two operator cases could be expressed as a @pytest.mark.parametrize table (similar to the adjacent test_prop_filter_json_extract_set_operators_handle_json_null_values test), making each case independently named and easier to debug in CI.

   Prompt To Fix With AI

   This is a comment left during a code review.
   Path: ee/clickhouse/models/test/test_property.py
   Line: 1856-1893
   
   Comment:
   **Non-parameterised test for the materialized case**
   
   The codebase convention is to prefer parameterised tests. `test_prop_filter_json_extract_set_operators_use_raw_json_when_materialized` tests `is_set` and `is_not_set` as separate assertions inside one test body. These two operator cases could be expressed as a `@pytest.mark.parametrize` table (similar to the adjacent `test_prop_filter_json_extract_set_operators_handle_json_null_values` test), making each case independently named and easier to debug in CI.
   
   How can I resolve this? If you propose a fix, please make it concise.

   Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

Prompt To Fix All With AI

Fix the following 3 code review issues. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 3
posthog/queries/base.py:115-120
The `is_not_set` block contains dead code. The guard at lines 86–87 (`if property.key not in override_property_values: raise ValidationError(...)`) guarantees that `key` is always in `override_property_values` by the time we reach this branch — so `if key in override_property_values:` is always `True` and the `raise` on line 120 can never be reached. The whole block reduces to a single `return`.

```suggestion
    if operator == "is_not_set":
        return override_value is None
```

### Issue 2 of 3
posthog/queries/base.py:83-84
The docstring comment on line 84 is now inaccurate. `is_not_set` is supported by this PR when the key exists in `override_property_values` with a `None` value.

```suggestion
    # only looks for matches where key exists in override_property_values
    # supports is_not_set when the key is present with a None value
```

### Issue 3 of 3
ee/clickhouse/models/test/test_property.py:1856-1893
**Non-parameterised test for the materialized case**

The codebase convention is to prefer parameterised tests. `test_prop_filter_json_extract_set_operators_use_raw_json_when_materialized` tests `is_set` and `is_not_set` as separate assertions inside one test body. These two operator cases could be expressed as a `@pytest.mark.parametrize` table (similar to the adjacent `test_prop_filter_json_extract_set_operators_handle_json_null_values` test), making each case independently named and easier to debug in CI.

_{Reviews (1): Last reviewed commit: "fix(cohorts): Treat null properties as u..." | Re-trigger Greptile}

[an8kk]

Fixed in 266afc6: simplified the is_not_set branch, updated the matcher comment, and parameterized the materialized-property test cases.