Issue IDNAError for the U-label "xn--" (fixes #82)

kjd · Mar 14, 2020 · efc1607 · efc1607 · olaure · May 28, 2020
1 parent 133fc01
commit efc1607
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diff --git a/idna/core.py b/idna/core.py
@@ -300,6 +300,8 @@ def ulabel(label):
     label = label.lower()
     if label.startswith(_alabel_prefix):
         label = label[len(_alabel_prefix):]
+        if not label:
+            raise IDNAError('Malformed A-label, no Punycode eligible content found')
         if label.decode('ascii')[-1] == '-':
             raise IDNAError('A-label must not end with a hyphen')
     else:

diff --git a/tests/test_idna.py b/tests/test_idna.py
@@ -258,6 +258,7 @@ def test_decode(self):
                          u'\u0521\u0525\u0523-\u0523\u0523-----\u0521\u0523\u0523\u0523.aa')
         self.assertRaises(idna.IDNAError, idna.decode, 'XN---------90GGLBAGAAC.AA')
         self.assertRaises(idna.IDNAError, idna.decode, 'xn---------90gglbagaac.aa')
+        self.assertRaises(idna.IDNAError, idna.decode, 'xn--')
 
 if __name__ == '__main__':
     unittest.main()