Refs #28643 -- Moved db function mixins to a separate module.

2 files changed, 48 insertions, 42 deletions

diff --git a/django/db/models/functions/math.py b/django/db/models/functions/math.py
index c8760652b4..43cbc17a1e 100644
--- a/django/db/models/functions/math.py
+++ b/django/db/models/functions/math.py
@@ -1,56 +1,35 @@
 import math
-import sys
 
 from django.db.models.expressions import Func
-from django.db.models.fields import DecimalField, FloatField, IntegerField
+from django.db.models.fields import FloatField, IntegerField
 from django.db.models.functions import Cast
+from django.db.models.functions.mixins import (
+    FixDecimalInputMixin, NumericOutputFieldMixin,
+)
 from django.db.models.lookups import Transform
 
 
-class DecimalInputMixin:
-
-    def as_postgresql(self, compiler, connection, **extra_context):
-        # Cast FloatField to DecimalField as PostgreSQL doesn't support the
-        # following function signatures:
-        # - LOG(double, double)
-        # - MOD(double, double)
-        output_field = DecimalField(decimal_places=sys.float_info.dig, max_digits=1000)
-        clone = self.copy()
-        clone.set_source_expressions([
-            Cast(expression, output_field) if isinstance(expression.output_field, FloatField)
-            else expression for expression in self.get_source_expressions()
-        ])
-        return clone.as_sql(compiler, connection, **extra_context)
-
-
-class OutputFieldMixin:
-
-    def _resolve_output_field(self):
-        has_decimals = any(isinstance(s.output_field, DecimalField) for s in self.get_source_expressions())
-        return DecimalField() if has_decimals else FloatField()
-
-
 class Abs(Transform):
     function = 'ABS'
     lookup_name = 'abs'
 
 
-class ACos(OutputFieldMixin, Transform):
+class ACos(NumericOutputFieldMixin, Transform):
     function = 'ACOS'
     lookup_name = 'acos'
 
 
-class ASin(OutputFieldMixin, Transform):
+class ASin(NumericOutputFieldMixin, Transform):
     function = 'ASIN'
     lookup_name = 'asin'
 
 
-class ATan(OutputFieldMixin, Transform):
+class ATan(NumericOutputFieldMixin, Transform):
     function = 'ATAN'
     lookup_name = 'atan'
 
 
-class ATan2(OutputFieldMixin, Func):
+class ATan2(NumericOutputFieldMixin, Func):
     function = 'ATAN2'
     arity = 2
 
@@ -80,12 +59,12 @@ class Ceil(Transform):
         return super().as_sql(compiler, connection, function='CEIL', **extra_context)
 
 
-class Cos(OutputFieldMixin, Transform):
+class Cos(NumericOutputFieldMixin, Transform):
     function = 'COS'
     lookup_name = 'cos'
 
 
-class Cot(OutputFieldMixin, Transform):
+class Cot(NumericOutputFieldMixin, Transform):
     function = 'COT'
     lookup_name = 'cot'
 
@@ -93,7 +72,7 @@ class Cot(OutputFieldMixin, Transform):
         return super().as_sql(compiler, connection, template='(1 / TAN(%(expressions)s))', **extra_context)
 
 
-class Degrees(OutputFieldMixin, Transform):
+class Degrees(NumericOutputFieldMixin, Transform):
     function = 'DEGREES'
     lookup_name = 'degrees'
 
@@ -105,7 +84,7 @@ class Degrees(OutputFieldMixin, Transform):
         )
 
 
-class Exp(OutputFieldMixin, Transform):
+class Exp(NumericOutputFieldMixin, Transform):
     function = 'EXP'
     lookup_name = 'exp'
 
@@ -115,12 +94,12 @@ class Floor(Transform):
     lookup_name = 'floor'
 
 
-class Ln(OutputFieldMixin, Transform):
+class Ln(NumericOutputFieldMixin, Transform):
     function = 'LN'
     lookup_name = 'ln'
 
 
-class Log(DecimalInputMixin, OutputFieldMixin, Func):
+class Log(FixDecimalInputMixin, NumericOutputFieldMixin, Func):
     function = 'LOG'
     arity = 2
 
@@ -134,12 +113,12 @@ class Log(DecimalInputMixin, OutputFieldMixin, Func):
         return clone.as_sql(compiler, connection, **extra_context)
 
 
-class Mod(DecimalInputMixin, OutputFieldMixin, Func):
+class Mod(FixDecimalInputMixin, NumericOutputFieldMixin, Func):
     function = 'MOD'
     arity = 2
 
 
-class Pi(OutputFieldMixin, Func):
+class Pi(NumericOutputFieldMixin, Func):
     function = 'PI'
     arity = 0
 
@@ -147,12 +126,12 @@ class Pi(OutputFieldMixin, Func):
         return super().as_sql(compiler, connection, template=str(math.pi), **extra_context)
 
 
-class Power(OutputFieldMixin, Func):
+class Power(NumericOutputFieldMixin, Func):
     function = 'POWER'
     arity = 2
 
 
-class Radians(OutputFieldMixin, Transform):
+class Radians(NumericOutputFieldMixin, Transform):
     function = 'RADIANS'
     lookup_name = 'radians'
 
@@ -169,16 +148,16 @@ class Round(Transform):
     lookup_name = 'round'
 
 
-class Sin(OutputFieldMixin, Transform):
+class Sin(NumericOutputFieldMixin, Transform):
     function = 'SIN'
     lookup_name = 'sin'
 
 
-class Sqrt(OutputFieldMixin, Transform):
+class Sqrt(NumericOutputFieldMixin, Transform):
     function = 'SQRT'
     lookup_name = 'sqrt'
 
 
-class Tan(OutputFieldMixin, Transform):
+class Tan(NumericOutputFieldMixin, Transform):
     function = 'TAN'
     lookup_name = 'tan'
diff --git a/django/db/models/functions/mixins.py b/django/db/models/functions/mixins.py
new file mode 100644
index 0000000000..1bf3d6cbd0
--- /dev/null
+++ b/django/db/models/functions/mixins.py
@@ -0,0 +1,27 @@
+import sys
+
+from django.db.models.fields import DecimalField, FloatField
+from django.db.models.functions import Cast
+
+
+class FixDecimalInputMixin:
+
+    def as_postgresql(self, compiler, connection, **extra_context):
+        # Cast FloatField to DecimalField as PostgreSQL doesn't support the
+        # following function signatures:
+        # - LOG(double, double)
+        # - MOD(double, double)
+        output_field = DecimalField(decimal_places=sys.float_info.dig, max_digits=1000)
+        clone = self.copy()
+        clone.set_source_expressions([
+            Cast(expression, output_field) if isinstance(expression.output_field, FloatField)
+            else expression for expression in self.get_source_expressions()
+        ])
+        return clone.as_sql(compiler, connection, **extra_context)
+
+
+class NumericOutputFieldMixin:
+
+    def _resolve_output_field(self):
+        has_decimals = any(isinstance(s.output_field, DecimalField) for s in self.get_source_expressions())
+        return DecimalField() if has_decimals else FloatField()