- Added a new type-level modifier :meth:`.TypeEngine.evaluates_none`

which indicates to the ORM that a positive set of None should be
persisted as the value NULL, instead of omitting the column from
the INSERT statement.  This feature is used both as part of the
implementation for :ticket:`3514` as well as a standalone feature
available on any type.  fixes #3250
- add new documentation section illustrating the "how to force null"
 use case of #3250
- alter our change from #3514 so that the class-level flag is now
called "should_evaluate_none"; so that "evaluates_none" is now
a generative method.

1 files changed, 46 insertions, 1 deletions

diff --git a/test/orm/test_unitofworkv2.py b/test/orm/test_unitofworkv2.py
index d4870adc6..09240dfdb 100644
--- a/test/orm/test_unitofworkv2.py
+++ b/test/orm/test_unitofworkv2.py
@@ -1964,7 +1964,7 @@ class NullEvaluatingTest(fixtures.MappedTest, testing.AssertsExecutionResults):
         class EvalsNull(TypeDecorator):
             impl = String(50)
 
-            evaluates_none = True
+            should_evaluate_none = True
 
             def process_bind_param(self, value, dialect):
                 if value is None:
@@ -1979,6 +1979,11 @@ class NullEvaluatingTest(fixtures.MappedTest, testing.AssertsExecutionResults):
             Column('evals_null_default', EvalsNull(), default='default_val'),
             Column('no_eval_null_no_default', String(50)),
             Column('no_eval_null_default', String(50), default='default_val'),
+            Column(
+                'builtin_evals_null_no_default', String(50).evaluates_none()),
+            Column(
+                'builtin_evals_null_default',
+                String(50).evaluates_none(), default='default_val'),
         )
 
     @classmethod
@@ -2121,3 +2126,43 @@ class NullEvaluatingTest(fixtures.MappedTest, testing.AssertsExecutionResults):
         self._test_bulk_insert_novalue(
             "no_eval_null_default", 'default_val'
         )
+
+    def test_builtin_evalnull_nodefault_insert(self):
+        self._test_insert(
+            "builtin_evals_null_no_default", None
+        )
+
+    def test_builtin_evalnull_nodefault_bulk_insert(self):
+        self._test_bulk_insert(
+            "builtin_evals_null_no_default", None
+        )
+
+    def test_builtin_evalnull_nodefault_insert_novalue(self):
+        self._test_insert_novalue(
+            "builtin_evals_null_no_default", None
+        )
+
+    def test_builtin_evalnull_nodefault_bulk_insert_novalue(self):
+        self._test_bulk_insert_novalue(
+            "builtin_evals_null_no_default", None
+        )
+
+    def test_builtin_evalnull_default_insert(self):
+        self._test_insert(
+            "builtin_evals_null_default", None
+        )
+
+    def test_builtin_evalnull_default_bulk_insert(self):
+        self._test_bulk_insert(
+            "builtin_evals_null_default", None
+        )
+
+    def test_builtin_evalnull_default_insert_novalue(self):
+        self._test_insert_novalue(
+            "builtin_evals_null_default", 'default_val'
+        )
+
+    def test_builtin_evalnull_default_bulk_insert_novalue(self):
+        self._test_bulk_insert_novalue(
+            "builtin_evals_null_default", 'default_val'
+        )