Double percent signs based on paramstyle, not dialect

This patch moves the "doubling" of percent signs into
the base compiler and makes it completely a product
of whether or not the paramstyle is format/pyformat or
not.   Without this paramstyle, percent signs
are not doubled across text(), literal_column(), and
column().

Change-Id: Ie2f278ab1dbb94b5078f85c0096d74dbfa049197
Fixes: #3740

1 files changed, 33 insertions, 1 deletions

diff --git a/lib/sqlalchemy/testing/suite/test_dialect.py b/lib/sqlalchemy/testing/suite/test_dialect.py
index 00884a212..0e62c347f 100644
--- a/lib/sqlalchemy/testing/suite/test_dialect.py
+++ b/lib/sqlalchemy/testing/suite/test_dialect.py
@@ -1,9 +1,11 @@
 from .. import fixtures, config
 from ..config import requirements
 from sqlalchemy import exc
-from sqlalchemy import Integer, String
+from sqlalchemy import Integer, String, select, literal_column
 from .. import assert_raises
 from ..schema import Table, Column
+from .. import provide_metadata
+from .. import eq_
 
 
 class ExceptionTest(fixtures.TablesTest):
@@ -39,3 +41,33 @@ class ExceptionTest(fixtures.TablesTest):
                 self.tables.manual_pk.insert(),
                 {'id': 1, 'data': 'd1'}
             )
+
+
+class EscapingTest(fixtures.TestBase):
+    @provide_metadata
+    def test_percent_sign_round_trip(self):
+        """test that the DBAPI accommodates for escaped / nonescaped
+        percent signs in a way that matches the compiler
+
+        """
+        m = self.metadata
+        t = Table('t', m, Column('data', String(50)))
+        t.create(config.db)
+        with config.db.begin() as conn:
+            conn.execute(t.insert(), dict(data="some % value"))
+            conn.execute(t.insert(), dict(data="some %% other value"))
+
+            eq_(
+                conn.scalar(
+                    select([t.c.data]).where(
+                        t.c.data == literal_column("'some % value'"))
+                ),
+                "some % value"
+            )
+
+            eq_(
+                conn.scalar(
+                    select([t.c.data]).where(
+                        t.c.data == literal_column("'some %% other value'"))
+                ), "some %% other value"
+            )