fix(api): scope NULL branch in NullableDatetimeRangeFilter for start_date lower bounds [fj4WqyCCw3C5ShR1RfB7MoBPTpkRrBFYP1uT35g3MvT]

[waterWang]

Description

NullableDatetimeRangeFilter was added in #66696 to replace COALESCE(column, now()) with index-friendly OR predicates. For lower bounds (gte/gt), the NULL branch passes unconditionally:

select = select.where(or_(self.attribute >= x, self.attribute.is_(None)))

This is correct for non-terminal rows (a not-yet-started task will eventually start). But it's wrong for terminal dag runs whose start_date is NULL — a failed/success run that never started will never have a start_date, yet it matches every start_date_gte filter forever.

Root cause

When querying GET /dags/~/dagRuns?start_date_gte=<recent-timestamp>, the response includes terminal dag runs from years ago (state: failed, start_date: null, populated end_date) as if they had just occurred. Roughly 99% of a -logical_date-ordered page are these stale null-start_date rows.

Fix

Add an extra_null_condition parameter to NullableDatetimeRangeFilter. For start_date lower bounds, the factory passes model.end_date.is_(None), so the NULL branch becomes:

or_(start_date >= x, and_(start_date IS NULL, end_date IS NULL))

A genuinely pending run has start_date IS NULL AND end_date IS NULL. A terminal run with NULL start_date has end_date IS NOT NULL and is correctly excluded.

Changes

• parameters.py: Add extra_null_condition to NullableDatetimeRangeFilter; update datetime_range_filter_factory to pass it for start_date
• test_parameters.py: Update existing lower-bound test to verify end_date IS NULL; add test for terminal-run exclusion

Related issues

Fixes #70627

[boring-cyborg]

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[ColtenOuO]

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