Invent a new utility to deal with native strings

beets/ui/commands.py

@@ -1617,7 +1617,7 @@ def config_func(lib, opts, args):
     # Dump configuration.
     else:
         config_out = config.dump(full=opts.defaults, redact=opts.redact)
-        print_(util.as_string(config_out))
+        print_(util.text_string(config_out))
 
 
 def config_edit():
@@ -1687,7 +1687,7 @@ def completion_script(commands):
     """
     base_script = os.path.join(_package_path('beets.ui'), 'completion_base.sh')
     with open(base_script, 'r') as base_script:
-        yield util.as_string(base_script.read())
+        yield util.text_string(base_script.read())
 
     options = {}
     aliases = {}

beets/util/__init__.py

@@ -647,6 +647,19 @@ def as_string(value):
         return six.text_type(value)
 
 
+def text_string(value, encoding='utf8'):
+    """Convert a string, which can either be bytes or unicode, to
+    unicode.
+
+    Text (unicode) is left untouched; bytes are decoded. This is useful
+    to convert from a "native string" (bytes on Python 2, str on Python
+    3) to a consistently unicode value.
+    """
+    if isinstance(value, bytes):
+        return value.decode(encoding)
+    return value
+
+
 def plurality(objs):
     """Given a sequence of hashble objects, returns the object that
     is most common in the set and the its number of appearance. The