Migrate basestring to a python3 compatible type (#17199)

lib/ansible/module_utils/pycompat24.py

@@ -42,3 +42,47 @@ def get_exception():
 
     """
     return sys.exc_info()[1]
+
+try:
+    # Python 2.6+
+    from ast import literal_eval
+except ImportError:
+    # a replacement for literal_eval that works with python 2.4. from:
+    # https://mail.python.org/pipermail/python-list/2009-September/551880.html
+    # which is essentially a cut/paste from an earlier (2.6) version of python's
+    # ast.py
+    from compiler import ast, parse
+    from ansible.module_utils.six import binary_type, string_types, text_type
+
+    def literal_eval(node_or_string):
+        """
+        Safely evaluate an expression node or a string containing a Python
+        expression.  The string or node provided may only consist of the  following
+        Python literal structures: strings, numbers, tuples, lists, dicts,  booleans,
+        and None.
+        """
+        _safe_names = {'None': None, 'True': True, 'False': False}
+        if isinstance(node_or_string, string_types):
+            node_or_string = parse(node_or_string, mode='eval')
+        if isinstance(node_or_string, ast.Expression):
+            node_or_string = node_or_string.node
+
+        def _convert(node):
+            # Okay to use long here because this is only for python 2.4 and 2.5
+            if isinstance(node, ast.Const) and isinstance(node.value, (text_type, binary_type, int, float, long, complex)):
+                return node.value
+            elif isinstance(node, ast.Tuple):
+                return tuple(map(_convert, node.nodes))
+            elif isinstance(node, ast.List):
+                return list(map(_convert, node.nodes))
+            elif isinstance(node, ast.Dict):
+                return dict((_convert(k), _convert(v)) for k, v in node.items())
+            elif isinstance(node, ast.Name):
+                if node.name in _safe_names:
+                    return _safe_names[node.name]
+            elif isinstance(node, ast.UnarySub):
+                return -_convert(node.expr)
+            raise ValueError('malformed string')
+        return _convert(node_or_string)
+
+__all__ = ('get_exception', 'literal_eval')