INTPYTHON-967 Add support for the ExtractQuarter database function

Author: timgraham

django_mongodb_backend/features.py

@@ -725,10 +725,6 @@ def django_test_skips(self):
         (NotSupportedError, "TruncDate with tzinfo (Africa/Nairobi) isn't supported on MongoDB."): {
             "timezones.tests.NewDatabaseTests.test_query_convert_timezones",
         },
-        (NotSupportedError, "ExtractQuarter is not supported."): {
-            "db_functions.datetime.test_extract_trunc.DateFunctionTests.test_extract_quarter_func",
-            "db_functions.datetime.test_extract_trunc.DateFunctionTests.test_extract_quarter_func_boundaries",
-        },
         (NotSupportedError, "StringAgg is not supported."): {
             "aggregation.tests.AggregateTestCase.test_distinct_on_stringagg",
             "aggregation.tests.AggregateTestCase.test_string_agg_escapes_delimiter",

django_mongodb_backend/functions.py

@@ -15,6 +15,7 @@
     ExtractIsoYear,
     ExtractMinute,
     ExtractMonth,
+    ExtractQuarter,
     ExtractSecond,
     ExtractWeek,
     ExtractWeekDay,
@@ -101,6 +102,9 @@ def cot(self, compiler, connection):
 
 def extract(self, compiler, connection):
     lhs_mql = process_lhs(self, compiler, connection, as_expr=True)
+    # ExtractQuarter lacks a built-in operator.
+    if self.lookup_name == "quarter":
+        return extract_quarter(self, compiler, connection)
     operator = EXTRACT_OPERATORS.get(self.lookup_name)
     if operator is None:
         raise NotSupportedError(f"{self.__class__.__name__} is not supported.")
@@ -109,6 +113,13 @@ def extract(self, compiler, connection):
     return {f"${operator}": lhs_mql}
 
 
+def extract_quarter(self, compiler, connection):
+    lhs_mql = process_lhs(self, compiler, connection, as_expr=True)
+    if timezone := self.get_tzname():
+        lhs_mql = {"date": lhs_mql, "timezone": timezone}
+    return {"$ceil": {"$divide": [{"$month": lhs_mql}, 3]}}
+
+
 def func(self, compiler, connection):
     lhs_mql = process_lhs(self, compiler, connection, as_expr=True)
     if self.function is None:
@@ -329,6 +340,7 @@ def register_functions():
     ConcatPair.as_mql_expr = concat_pair
     Cot.as_mql_expr = cot
     Extract.as_mql_expr = extract
+    ExtractQuarter.as_mql_expr = extract_quarter
     Func.as_mql_expr = func
     Func.can_use_path = False
     JSONArray.as_mql_expr = partialmethod(process_lhs, as_expr=True)

docs/releases/6.0.x.rst

@@ -12,6 +12,7 @@ New features
 
 - Added support for the following database functions:
 
+  - :class:`~django.db.models.functions.ExtractQuarter`
   - :class:`~django.db.models.functions.MD5` (requires MongoDB 8.3+)
   - :class:`~django.db.models.functions.Right`
   - :class:`~django.db.models.functions.SHA256` (requires MongoDB 8.3+)

docs/topics/known-issues.rst

@@ -76,7 +76,6 @@ Database functions
 - Some of Django's built-in database functions aren't supported by MongoDB:
 
   - :class:`~django.db.models.functions.Chr`
-  - :class:`~django.db.models.functions.ExtractQuarter`
   - :class:`~django.db.models.functions.LPad`,
     :class:`~django.db.models.functions.RPad`
   - :class:`~django.db.models.functions.Ord`