basestring and str are gone since Python 3

alembic/autogenerate.py

@@ -1,6 +1,10 @@
 """Provide the 'autogenerate' feature which can produce migration operations
 automatically."""
 
+try:
+    import builtins
+except ImportError:
+    import __builtin__ as builtins
 import logging
 import re
 
@@ -584,17 +588,18 @@ def _render_column(column, autogen_context):
     }
 
 def _render_server_default(default, autogen_context):
+    string_type = getattr(builtins, 'basestring', str)
     rendered = _user_defined_render("server_default", default, autogen_context)
     if rendered is not False:
         return rendered
 
     if isinstance(default, sa_schema.DefaultClause):
-        if isinstance(default.arg, basestring):
+        if isinstance(default.arg, string_type):
             default = default.arg
         else:
             default = str(default.arg.compile(
                             dialect=autogen_context['dialect']))
-    if isinstance(default, basestring):
+    if isinstance(default, string_type):
         # TODO: this is just a hack to get
         # tests to pass until we figure out
         # WTF sqlite is doing

alembic/ddl/impl.py

@@ -1,3 +1,8 @@
+try:
+    import builtins
+except ImportError:
+    import __builtin__ as builtins
+
 from sqlalchemy.sql.expression import _BindParamClause
 from sqlalchemy.ext.compiler import compiles
 from sqlalchemy import schema, text
@@ -58,12 +63,13 @@ class DefaultImpl(ImplMeta('_ImplBase', (object,), {})):
     def _exec(self, construct, execution_options=None,
                             multiparams=(),
                             params=util.immutabledict()):
-        if isinstance(construct, basestring):
+        if isinstance(construct, getattr(builtins, 'basestring', str)):
             construct = text(construct)
         if self.as_sql:
             if multiparams or params:
                 # TODO: coverage
                 raise Exception("Execution arguments not allowed with as_sql")
+            unicode = getattr(builtins, 'unicode', str)
             self.static_output(unicode(
                     construct.compile(dialect=self.dialect)
                     ).replace("\t", "    ").strip() + self.command_terminator)

alembic/ddl/mysql.py

@@ -1,3 +1,8 @@
+try:
+    import builtins
+except ImportError:
+    import __builtin__ as builtins
+
 from sqlalchemy.ext.compiler import compiles
 from sqlalchemy import types as sqltypes
 from sqlalchemy import schema
@@ -89,7 +94,7 @@ def _mysql_alter_column(element, compiler, **kw):
     )
 
 def _render_value(compiler, expr):
-    if isinstance(expr, basestring):
+    if isinstance(expr, getattr(builtins, 'basestring', str)):
         return "'%s'" % expr
     else:
         return compiler.sql_compiler.process(expr)

alembic/operations.py

@@ -1,3 +1,7 @@
+try:
+    import builtins
+except ImportError:
+    import __builtin__ as builtins
 from contextlib import contextmanager
 
 from sqlalchemy.types import NULLTYPE, Integer
@@ -143,7 +147,7 @@ class Operations(object):
         ForeignKey.
 
         """
-        if isinstance(fk._colspec, basestring):
+        if isinstance(fk._colspec, getattr(builtins, 'basestring', str)):
             table_key, cname = fk._colspec.rsplit('.', 1)
             sname, tname = self._parse_table_key(table_key)
             if table_key not in metadata.tables:

tests/__init__.py

@@ -97,6 +97,7 @@ def _get_dialect(name):
 
 def assert_compiled(element, assert_string, dialect=None):
     dialect = _get_dialect(dialect)
+    unicode = getattr(builtins, 'unicode', str)
     eq_(
         unicode(element.compile(dialect=dialect)).\
                     replace("\n", "").replace("\t", ""),
@@ -160,6 +161,8 @@ def op_fixture(dialect='default', as_sql=False):
             # as tests get more involved
             self.connection = None
         def _exec(self, construct, *args, **kw):
+            basestring = getattr(builtins, 'basestring', str)
+            unicode = getattr(builtins, 'unicode', str)
             if isinstance(construct, basestring):
                 construct = text(construct)
             sql = unicode(construct.compile(dialect=self.dialect))
@@ -315,6 +318,8 @@ def clear_staging_env():
 def write_script(scriptdir, rev_id, content):
     old = scriptdir._revision_map[rev_id]
     path = old.path
+    if not hasattr(builtins, 'unicode') and isinstance(content, bytes):
+        content = content.decode()
     with open(path, 'w') as fp:
         fp.write(textwrap.dedent(content))
     pyc_path = util.pyc_file_from_path(path)

tests/test_autogenerate.py

@@ -667,7 +667,7 @@ class AutogenerateDiffTest(AutogenTest, TestCase):
         )
         eq_(
             [(rec[0], rec[1].name) for rec in diffs],
-            [('remove_table', 'extra'), ('remove_table', u'user')]
+            [('remove_table', 'extra'), ('remove_table', 'user')]
         )
 
 class AutogenKeyTest(AutogenTest, TestCase):