Apply percent sign escaping to literal binds, comments

Fixed bug in new percent-sign support (e.g. :ticket:`3740`) where a bound
parameter rendered with literal_binds would fail to escape percent-signs
for relevant dialects.  In addition, ensured new table / column comment
support feature also fully makes use of literal-rendered parameters so that
this percent sign support takes place with table / column comment DDL as
well, allowing percent sign support for the mysql / psycopg2 backends that
require escaping of percent signs.

Change-Id: Ia4136a300933e9bc6a01a7b9afd5c7b9a3fee4e3
Fixes: #4054
Fixes: #4052

4 files changed, 22 insertions, 6 deletions

diff --git a/lib/sqlalchemy/dialects/mysql/base.py b/lib/sqlalchemy/dialects/mysql/base.py
index 0cffae389..9d6dd7188 100644
--- a/lib/sqlalchemy/dialects/mysql/base.py
+++ b/lib/sqlalchemy/dialects/mysql/base.py
@@ -1171,7 +1171,9 @@ class MySQLDDLCompiler(compiler.DDLCompiler):
         ], nonpart_options):
             arg = opts[opt]
             if opt in _reflection._options_of_type_string:
-                arg = "'%s'" % arg.replace("\\", "\\\\").replace("'", "''")
+
+                arg = self.sql_compiler.render_literal_value(
+                    arg, sqltypes.String())
 
             if opt in ('DATA_DIRECTORY', 'INDEX_DIRECTORY',
                        'DEFAULT_CHARACTER_SET', 'CHARACTER_SET',
@@ -1196,7 +1198,8 @@ class MySQLDDLCompiler(compiler.DDLCompiler):
         ], part_options):
             arg = opts[opt]
             if opt in _reflection._options_of_type_string:
-                arg = "'%s'" % arg.replace("\\", "\\\\").replace("'", "''")
+                arg = self.sql_compiler.render_literal_value(
+                    arg, sqltypes.String())
 
             opt = opt.replace('_', ' ')
             joiner = ' '
diff --git a/lib/sqlalchemy/sql/sqltypes.py b/lib/sqlalchemy/sql/sqltypes.py
index 6838baa5f..fe9a56b6e 100644
--- a/lib/sqlalchemy/sql/sqltypes.py
+++ b/lib/sqlalchemy/sql/sqltypes.py
@@ -205,6 +205,10 @@ class String(Concatenable, TypeEngine):
     def literal_processor(self, dialect):
         def process(value):
             value = value.replace("'", "''")
+
+            if dialect.identifier_preparer._double_percents:
+                value = value.replace('%', '%%')
+
             return "'%s'" % value
         return process
 
diff --git a/lib/sqlalchemy/testing/suite/test_reflection.py b/lib/sqlalchemy/testing/suite/test_reflection.py
index 54b59a432..7674338b4 100644
--- a/lib/sqlalchemy/testing/suite/test_reflection.py
+++ b/lib/sqlalchemy/testing/suite/test_reflection.py
@@ -104,9 +104,12 @@ class ComponentReflectionTest(fixtures.TablesTest):
               )
         Table('comment_test', metadata,
               Column('id', sa.Integer, primary_key=True, comment='id comment'),
-              Column('data', sa.String(20), comment='data comment'),
+              Column('data', sa.String(20), comment='data % comment'),
+              Column(
+                  'd2', sa.String(20),
+                  comment=r"""Comment types type speedily ' " \ '' Fun!"""),
               schema=schema,
-              comment='the test table comment')
+              comment=r"""the test % ' " \ table comment""")
 
         if testing.requires.index_reflection.enabled:
             cls.define_index(metadata, users)
@@ -274,7 +277,7 @@ class ComponentReflectionTest(fixtures.TablesTest):
 
         eq_(
             insp.get_table_comment("comment_test", schema=schema),
-            {"text": "the test table comment"}
+            {"text": r"""the test % ' " \ table comment"""}
         )
 
         eq_(
@@ -290,7 +293,9 @@ class ComponentReflectionTest(fixtures.TablesTest):
             ],
             [
                 {'comment': 'id comment', 'name': 'id'},
-                {'comment': 'data comment', 'name': 'data'}
+                {'comment': 'data % comment', 'name': 'data'},
+                {'comment': r"""Comment types type speedily ' " \ '' Fun!""",
+                 'name': 'd2'}
             ]
         )
 
diff --git a/lib/sqlalchemy/testing/suite/test_types.py b/lib/sqlalchemy/testing/suite/test_types.py
index a345454be..83aac2850 100644
--- a/lib/sqlalchemy/testing/suite/test_types.py
+++ b/lib/sqlalchemy/testing/suite/test_types.py
@@ -187,6 +187,10 @@ class TextTest(_LiteralRoundTripFixture, fixtures.TablesTest):
         data = r'backslash one \ backslash two \\ end'
         self._literal_round_trip(Text, [data], [data])
 
+    def test_literal_percentsigns(self):
+        data = r'percent % signs %% percent'
+        self._literal_round_trip(Text, [data], [data])
+
 
 class StringTest(_LiteralRoundTripFixture, fixtures.TestBase):
     __backend__ = True