Remove all remaining removed_in_20 warnings slated for removal

Finalize all remaining removed-in-2.0 changes so that we
can begin doing pep-484 typing without old things
getting in the way (we will also have to do public_factory).

note there are a few "moved_in_20()" and "became_legacy_in_20()"
warnings still in place.  The SQLALCHEMY_WARN_20 variable
is now removed.

Also removed here are the legacy "in place mutators" for Select
statements, and some keyword-only argument signatures in Core
have been added.

Also in the big change department, the ORM mapper() function
is removed entirely; the Mapper class is otherwise unchanged,
just the public-facing API function.  Mappers are now always
given a registry in which to participate, however the
argument signature of Mapper is not changed. ideally "registry"
would be the first positional argument.

Fixes: #7257

Change-Id: Ic70c57b9f1cf7eb996338af5183b11bdeb3e1623

1 files changed, 11 insertions, 0 deletions

diff --git a/test/sql/test_selectable.py b/test/sql/test_selectable.py
index c3a2d8d3c..a63ae5be4 100644
--- a/test/sql/test_selectable.py
+++ b/test/sql/test_selectable.py
@@ -608,6 +608,17 @@ class SelectableTest(
             "table1.col3, table1.colx FROM table1) AS anon_1",
         )
 
+    def test_with_only_generative_no_list(self):
+        s1 = table1.select().scalar_subquery()
+
+        with testing.expect_raises_message(
+            exc.ArgumentError,
+            r"The \"columns\" argument to "
+            r"Select.with_only_columns\(\), when referring "
+            "to a sequence of items, is now passed",
+        ):
+            s1.with_only_columns([s1])
+
     @testing.combinations(
         (
             [table1.c.col1],