don't cache TypeDecorator by default

The :class:`.TypeDecorator` class will now emit a warning when used in SQL
compilation with caching unless the ``.cache_ok`` flag is set to ``True``
or ``False``. ``.cache_ok`` indicates that all the parameters passed to the
object are safe to be used as a cache key, ``False`` means they are not.

Fixes: #6436
Change-Id: Ib1bb7dc4b124e38521d615c2e2e691e4915594fb

1 files changed, 5 insertions, 0 deletions

diff --git a/test/sql/test_operators.py b/test/sql/test_operators.py
index 8fe802bf3..932d30742 100644
--- a/test/sql/test_operators.py
+++ b/test/sql/test_operators.py
@@ -500,6 +500,7 @@ class TypeDecoratorComparatorTest(_CustomComparatorTests, fixtures.TestBase):
     def _add_override_factory(self):
         class MyInteger(TypeDecorator):
             impl = Integer
+            cache_ok = True
 
             class comparator_factory(TypeDecorator.Comparator):
                 def __init__(self, expr):
@@ -520,6 +521,7 @@ class TypeDecoratorTypeDecoratorComparatorTest(
     def _add_override_factory(self):
         class MyIntegerOne(TypeDecorator):
             impl = Integer
+            cache_ok = True
 
             class comparator_factory(TypeDecorator.Comparator):
                 def __init__(self, expr):
@@ -533,6 +535,7 @@ class TypeDecoratorTypeDecoratorComparatorTest(
 
         class MyIntegerTwo(TypeDecorator):
             impl = MyIntegerOne
+            cache_ok = True
 
         return MyIntegerTwo
 
@@ -556,6 +559,7 @@ class TypeDecoratorWVariantComparatorTest(
 
         class MyInteger(TypeDecorator):
             impl = Integer
+            cache_ok = True
 
             class comparator_factory(TypeDecorator.Comparator):
                 def __init__(self, expr):
@@ -587,6 +591,7 @@ class CustomEmbeddedinTypeDecoratorTest(
 
         class MyDecInteger(TypeDecorator):
             impl = MyInteger
+            cache_ok = True
 
         return MyDecInteger