apply basic escaping to anon_labels unconditionally

Fixed issue which prevented the :func:`_sql.literal_column` construct from
working properly within the context of a :class:`.Select` construct as well
as other potential places where "anonymized labels" might be generated, if
the literal expression contained characters which could interfere with
format strings, such as open parenthesis, due to an implementation detail
of the "anonymous label" structure.

Fixes: #8724
Change-Id: I3089124fbd055a011c8a245964258503b717d941

1 files changed, 34 insertions, 0 deletions

diff --git a/test/sql/test_labels.py b/test/sql/test_labels.py
index d385b9e8d..42d9c5f00 100644
--- a/test/sql/test_labels.py
+++ b/test/sql/test_labels.py
@@ -3,6 +3,7 @@ from sqlalchemy import Boolean
 from sqlalchemy import cast
 from sqlalchemy import exc as exceptions
 from sqlalchemy import Integer
+from sqlalchemy import literal_column
 from sqlalchemy import MetaData
 from sqlalchemy import or_
 from sqlalchemy import select
@@ -20,6 +21,7 @@ from sqlalchemy.sql.elements import _truncated_label
 from sqlalchemy.sql.elements import ColumnElement
 from sqlalchemy.sql.elements import WrapsColumnExpression
 from sqlalchemy.sql.selectable import LABEL_STYLE_NONE
+from sqlalchemy.sql.visitors import prefix_anon_map
 from sqlalchemy.testing import assert_raises
 from sqlalchemy.testing import assert_raises_message
 from sqlalchemy.testing import AssertsCompiledSQL
@@ -1038,3 +1040,35 @@ class ColExprLabelTest(fixtures.TestBase, AssertsCompiledSQL):
             "SOME_COL_THING(some_table.value) "
             "AS some_table_value FROM some_table",
         )
+
+    @testing.combinations(
+        # the resulting strings are completely arbitrary and are not
+        # exposed in SQL with current implementations.  we want to
+        # only assert that the operation doesn't fail.  It's safe to
+        # change the assertion cases for this test if the label escaping
+        # format changes
+        (literal_column("'(1,2]'"), "'_1,2]'_1"),
+        (literal_column("))"), "__1"),
+        (literal_column("'%('"), "'_'_1"),
+    )
+    def test_labels_w_strformat_chars_in_isolation(self, test_case, expected):
+        """test #8724"""
+
+        pa = prefix_anon_map()
+        eq_(test_case._anon_key_label % pa, expected)
+
+    @testing.combinations(
+        (
+            select(literal_column("'(1,2]'"), literal_column("'(1,2]'")),
+            "SELECT '(1,2]', '(1,2]'",
+        ),
+        (select(literal_column("))"), literal_column("))")), "SELECT )), ))"),
+        (
+            select(literal_column("'%('"), literal_column("'%('")),
+            "SELECT '%(', '%('",
+        ),
+    )
+    def test_labels_w_strformat_chars_in_statements(self, test_case, expected):
+        """test #8724"""
+
+        self.assert_compile(test_case, expected)