Added DatabaseOperations.convert_trunc_expression() hook.

Needed on MongoDB.

2 files changed, 21 insertions, 20 deletions

diff --git a/django/db/backends/base/operations.py b/django/db/backends/base/operations.py
index fac6215899..bc1752df6f 100644
--- a/django/db/backends/base/operations.py
+++ b/django/db/backends/base/operations.py
@@ -7,7 +7,7 @@ from itertools import chain
 import sqlparse
 
 from django.conf import settings
-from django.db import NotSupportedError, transaction
+from django.db import NotSupportedError, models, transaction
 from django.db.models.expressions import Col
 from django.db.models.fields.composite import CompositePrimaryKey
 from django.utils import timezone
@@ -684,6 +684,25 @@ class BaseDatabaseOperations:
         if value is not None:
             return datetime.timedelta(0, 0, value)
 
+    def convert_trunc_expression(self, value, expression):
+        if isinstance(expression.output_field, models.DateTimeField):
+            if not settings.USE_TZ:
+                pass
+            elif value is not None:
+                value = value.replace(tzinfo=None)
+                value = timezone.make_aware(value, expression.tzinfo)
+            elif not self.connection.features.has_zoneinfo_database:
+                raise ValueError(
+                    "Database returned an invalid datetime value. Are time "
+                    "zone definitions for your database installed?"
+                )
+        elif isinstance(value, datetime.datetime):
+            if isinstance(expression.output_field, models.DateField):
+                value = value.date()
+            elif isinstance(expression.output_field, models.TimeField):
+                value = value.time()
+        return value
+
     def check_expression_support(self, expression):
         """
         Check that the backend supports the provided expression.
diff --git a/django/db/models/functions/datetime.py b/django/db/models/functions/datetime.py
index b536690c8a..842987bf26 100644
--- a/django/db/models/functions/datetime.py
+++ b/django/db/models/functions/datetime.py
@@ -1,5 +1,3 @@
-from datetime import datetime
-
 from django.conf import settings
 from django.db.models.expressions import Func
 from django.db.models.fields import (
@@ -344,23 +342,7 @@ class TruncBase(TimezoneMixin, Transform):
         return copy
 
     def convert_value(self, value, expression, connection):
-        if isinstance(self.output_field, DateTimeField):
-            if not settings.USE_TZ:
-                pass
-            elif value is not None:
-                value = value.replace(tzinfo=None)
-                value = timezone.make_aware(value, self.tzinfo)
-            elif not connection.features.has_zoneinfo_database:
-                raise ValueError(
-                    "Database returned an invalid datetime value. Are time "
-                    "zone definitions for your database installed?"
-                )
-        elif isinstance(value, datetime):
-            if isinstance(self.output_field, DateField):
-                value = value.date()
-            elif isinstance(self.output_field, TimeField):
-                value = value.time()
-        return value
+        return connection.ops.convert_trunc_expression(value, expression)
 
 
 class Trunc(TruncBase):