Merge pull request #2 from akshat62/s4lmj0-codex/fix-bug-related-to-issue-62094

Preserve day freq on DatetimeIndex subtraction

Author: akshat62

doc/source/whatsnew/v3.0.0.rst

@@ -758,6 +758,10 @@ Datetimelike
 - Bug in :meth:`to_datetime` reports incorrect index in case of any failure scenario. (:issue:`58298`)
 - Bug in :meth:`to_datetime` with ``format="ISO8601"`` and ``utc=True`` where naive timestamps incorrectly inherited timezone offset from previous timestamps in a series. (:issue:`61389`)
 - Bug in :meth:`to_datetime` wrongly converts when ``arg`` is a ``np.datetime64`` object with unit of ``ps``. (:issue:`60341`)
+- Bug in subtracting a :class:`Timestamp` from a :class:`DatetimeIndex` with
+  ``freq="D"`` dropping the frequency and causing subsequent
+  :meth:`TimedeltaIndex.shift` calls to raise ``NullFrequencyError``
+  (:issue:`62094`)
 - Bug in constructing arrays with :class:`ArrowDtype` with ``timestamp`` type incorrectly allowing ``Decimal("NaN")`` (:issue:`61773`)
 - Bug in constructing arrays with a timezone-aware :class:`ArrowDtype` from timezone-naive datetime objects incorrectly treating those as UTC times instead of wall times like :class:`DatetimeTZDtype` (:issue:`61775`)
 - Bug in setting scalar values with mismatched resolution into arrays with non-nanosecond ``datetime64``, ``timedelta64`` or :class:`DatetimeTZDtype` incorrectly truncating those scalars (:issue:`56410`)