Fixed #26348 -- Added TruncTime and exposed it through the __time lookup.

Thanks Tim for the review.

3 files changed, 40 insertions, 0 deletions

diff --git a/docs/ref/models/database-functions.txt b/docs/ref/models/database-functions.txt
index 20ceadde91..74198ed749 100644
--- a/docs/ref/models/database-functions.txt
+++ b/docs/ref/models/database-functions.txt
@@ -686,6 +686,17 @@ that deal with time-parts can be used with ``TimeField``::
 truncate function. It's also registered as a transform on  ``DateTimeField`` as
 ``__date``.
 
+.. class:: TruncTime(expression, **extra)
+
+.. versionadded:: 1.11
+
+    .. attribute:: lookup_name = 'time'
+    .. attribute:: output_field = TimeField()
+
+``TruncTime`` casts ``expression`` to a time rather than using the built-in SQL
+truncate function. It's also registered as a transform on ``DateTimeField`` as
+``__time``.
+
 .. class:: TruncDay(expression, output_field=None, tzinfo=None, **extra)
 
     .. attribute:: kind = 'day'
diff --git a/docs/ref/models/querysets.txt b/docs/ref/models/querysets.txt
index 6985da5ca6..36d791db0e 100644
--- a/docs/ref/models/querysets.txt
+++ b/docs/ref/models/querysets.txt
@@ -2674,6 +2674,27 @@ When :setting:`USE_TZ` is ``True``, datetime fields are converted to the
 current time zone before filtering. This requires :ref:`time zone definitions
 in the database <database-time-zone-definitions>`.
 
+.. fieldlookup:: time
+
+``time``
+~~~~~~~~
+
+.. versionadded:: 1.11
+
+For datetime fields, casts the value as time. Allows chaining additional field
+lookups. Takes a :class:`datetime.time` value.
+
+Example::
+
+    Entry.objects.filter(pub_date__time=datetime.time(14, 30))
+    Entry.objects.filter(pub_date__time__between=(datetime.time(8), datetime.time(17)))
+
+(No equivalent SQL code fragment is included for this lookup because
+implementation of the relevant query varies among different database engines.)
+
+When :setting:`USE_TZ` is ``True``, fields are converted to the current time
+zone before filtering.
+
 .. fieldlookup:: hour
 
 ``hour``
diff --git a/docs/releases/1.11.txt b/docs/releases/1.11.txt
index 392ded70b8..0ed83a1da8 100644
--- a/docs/releases/1.11.txt
+++ b/docs/releases/1.11.txt
@@ -201,6 +201,10 @@ Models
 * Added support for time truncation to
   :class:`~django.db.models.functions.datetime.Trunc` functions.
 
+* Added the :class:`~django.db.models.functions.datetime.TruncTime` function
+  to truncate :class:`~django.db.models.DateTimeField` to its time component
+  and exposed it through the :lookup:`time` lookup.
+
 Requests and Responses
 ~~~~~~~~~~~~~~~~~~~~~~
 
@@ -273,6 +277,10 @@ Database backend API
   ``lookup_type`` argument can be either ``'hour'``, ``'minute'``, or
   ``'second'``.
 
+* The ``DatabaseOperations.datetime_cast_time_sql()`` method is added to
+  support the :lookup:`time` lookup. It accepts a ``field_name`` and ``tzname``
+  arguments and returns the SQL necessary to cast a datetime value to time value.
+
 Dropped support for PostgreSQL 9.2 and PostGIS 2.0
 --------------------------------------------------