Py3: correctly guess the signature of ObjectPath(...) and Signature(...)

Under Python 2, ObjectPath and Signature are subtypes of str (= bytes),
and the existing type-guessing worked.

The type-guessing code assumed that all unicode objects were just
strings, but that assumption became false in the Python 3 port:
ObjectPath and Signature are still subtypes of str, but str now means
unicode, not bytes.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=50740

2 files changed, 14 insertions, 2 deletions

diff --git a/_dbus_bindings/message-append.c b/_dbus_bindings/message-append.c
index f4f843b..df3190d 100644
--- a/_dbus_bindings/message-append.c
+++ b/_dbus_bindings/message-append.c
@@ -249,8 +249,16 @@ _signature_string_from_pyobject(PyObject *obj, long *variant_level_ptr)
             return NATIVESTR_FROMSTR(DBUS_TYPE_INT64_AS_STRING);
     }
 #endif  /* PY3 */
-    else if (PyUnicode_Check(obj))
-        return NATIVESTR_FROMSTR(DBUS_TYPE_STRING_AS_STRING);
+    else if (PyUnicode_Check(obj)) {
+        /* Object paths and signatures are unicode subtypes in Python 3
+         * (the first two cases will never be true in Python 2) */
+        if (DBusPyObjectPath_Check(obj))
+            return NATIVESTR_FROMSTR(DBUS_TYPE_OBJECT_PATH_AS_STRING);
+        else if (DBusPySignature_Check(obj))
+            return NATIVESTR_FROMSTR(DBUS_TYPE_SIGNATURE_AS_STRING);
+        else
+            return NATIVESTR_FROMSTR(DBUS_TYPE_STRING_AS_STRING);
+    }
 #if defined(DBUS_TYPE_UNIX_FD)
     else if (DBusPyUnixFd_Check(obj))
         return NATIVESTR_FROMSTR(DBUS_TYPE_UNIX_FD_AS_STRING);
@@ -266,6 +274,8 @@ _signature_string_from_pyobject(PyObject *obj, long *variant_level_ptr)
             return NATIVESTR_FROMSTR(DBUS_TYPE_DOUBLE_AS_STRING);
     }
     else if (PyBytes_Check(obj)) {
+        /* Object paths and signatures are bytes subtypes in Python 2
+         * (the first two cases will never be true in Python 3) */
         if (DBusPyObjectPath_Check(obj))
             return NATIVESTR_FROMSTR(DBUS_TYPE_OBJECT_PATH_AS_STRING);
         else if (DBusPySignature_Check(obj))
diff --git a/test/test-standalone.py b/test/test-standalone.py
index 95b636a..6f403ee 100755
--- a/test/test-standalone.py
+++ b/test/test-standalone.py
@@ -322,6 +322,8 @@ class TestMessageMarshalling(unittest.TestCase):
         aeq(Message.guess_signature(('a',)), '(s)')
         aeq(Message.guess_signature(['a']), 'as')
         aeq(Message.guess_signature({'a':'b'}), 'a{ss}')
+        aeq(Message.guess_signature(types.ObjectPath('/')), 'o')
+        aeq(Message.guess_signature(types.Signature('x')), 'g')
 
     def test_guess_signature_python_ints(self):
         aeq = self.assertEqual