Ensure escaping of percent signs in columns, parameters

Improved support for column names that contain percent signs in the string,
including repaired issues involving anoymous labels that also embedded a
column name with a percent sign in it, as well as re-established support
for bound parameter names with percent signs embedded on the psycopg2
dialect, using a late-escaping process similar to that used by the
cx_Oracle dialect.

* Added new constructor for _anonymous_label() that ensures incoming
  string tokens based on column or table names will have percent
  signs escaped; abstracts away the format of the label.

* generalized cx_Oracle's quoted_bind_names facility into the compiler
  itself, and leveraged this for the psycopg2 dialect's issue with
  percent signs in names as well.  the parameter substitution is now
  integrated with compiler.construct_parameters() as well as the
  recently reworked set_input_sizes(), reducing verbosity in the
  cx_Oracle dialect.

Fixes: #5653

Change-Id: Ia2ad13ea68b4b0558d410026e5a33f5cb3fbab2c

2 files changed, 19 insertions, 1 deletions

diff --git a/test/sql/test_compiler.py b/test/sql/test_compiler.py
index ffabf9379..ef2f75b2d 100644
--- a/test/sql/test_compiler.py
+++ b/test/sql/test_compiler.py
@@ -941,6 +941,24 @@ class SelectTest(fixtures.TestBase, AssertsCompiledSQL):
             "AS z FROM keyed) AS anon_2) AS anon_1",
         )
 
+    @testing.combinations("per cent", "per % cent", "%percent")
+    def test_percent_names_collide_with_anonymizing(self, name):
+        table1 = table("t1", column(name))
+
+        jj = select(table1.c[name]).subquery()
+        jjj = join(table1, jj, table1.c[name] == jj.c[name])
+
+        j2 = jjj.select().apply_labels().subquery("foo")
+
+        self.assert_compile(
+            j2.select(),
+            'SELECT foo."t1_%(name)s", foo."anon_1_%(name)s" FROM '
+            '(SELECT t1."%(name)s" AS "t1_%(name)s", anon_1."%(name)s" '
+            'AS "anon_1_%(name)s" FROM t1 JOIN (SELECT t1."%(name)s" AS '
+            '"%(name)s" FROM t1) AS anon_1 ON t1."%(name)s" = '
+            'anon_1."%(name)s") AS foo' % {"name": name},
+        )
+
     def test_exists(self):
         s = select(table1.c.myid).where(table1.c.myid == 5)
 
diff --git a/test/sql/test_selectable.py b/test/sql/test_selectable.py
index b98fbd3d0..c75e8886d 100644
--- a/test/sql/test_selectable.py
+++ b/test/sql/test_selectable.py
@@ -740,7 +740,7 @@ class SelectableTest(
         assert u2.corresponding_column(s1.selected_columns.col1) is u2.c.col1
         assert u2.corresponding_column(s2.selected_columns.col1) is u2.c.col1
 
-    def test_foo(self):
+    def test_union_alias_misc(self):
         s1 = select(table1.c.col1, table1.c.col2)
         s2 = select(table1.c.col2, table1.c.col1)