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, 13 insertions, 0 deletions

diff --git a/test/sql/test_text.py b/test/sql/test_text.py
index 4a273e1ee..ca4d10702 100644
--- a/test/sql/test_text.py
+++ b/test/sql/test_text.py
@@ -317,6 +317,19 @@ class BindParamTest(fixtures.TestBase, AssertsCompiledSQL):
             checkparams={'y': 6, 'x': 5, 'z': 7}
         )
 
+    def test_escaping_percent_signs(self):
+        stmt = text("select '%' where foo like '%bar%'")
+        self.assert_compile(
+            stmt,
+            "select '%' where foo like '%bar%'",
+            dialect="sqlite"
+        )
+
+        self.assert_compile(
+            stmt,
+            "select '%%' where foo like '%%bar%%'",
+            dialect="mysql"
+        )
 
 class AsFromTest(fixtures.TestBase, AssertsCompiledSQL):
     __dialect__ = 'default'