From: Martin v. Löwis <martin@v.loewis.de>
Date: Sat, 17 Apr 2004 19:36:48 +0000 (+0000)
Subject: Special case normalization of empty strings. Fixes #924361.
X-Git-Tag: v2.4a1~486
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=61e40bd897da8ab4bf2dffe817d0163e984c1e40;p=python

Special case normalization of empty strings. Fixes #924361.
Backported to 2.3.
---

diff --git a/Lib/test/test_unicodedata.py b/Lib/test/test_unicodedata.py
index 61b4ffb133..8157fb38e4 100644
--- a/Lib/test/test_unicodedata.py
+++ b/Lib/test/test_unicodedata.py
@@ -170,6 +170,7 @@ class UnicodeFunctionsTest(UnicodeDatabaseTest):
     def test_normalize(self):
         self.assertRaises(TypeError, self.db.normalize)
         self.assertRaises(ValueError, self.db.normalize, 'unknown', u'xx')
+        self.assertEqual(self.db.normalize('NFKC', u''), u'')
         # The rest can be found in test_normalization.py
         # which requires an external file.
 
diff --git a/Modules/unicodedata.c b/Modules/unicodedata.c
index 311db296bd..ba218a3e58 100644
--- a/Modules/unicodedata.c
+++ b/Modules/unicodedata.c
@@ -515,6 +515,13 @@ unicodedata_normalize(PyObject *self, PyObject *args)
                          &form, &PyUnicode_Type, &input))
         return NULL;
 
+    if (PyUnicode_GetSize(input) == 0) {
+        /* Special case empty input strings, since resizing
+           them  later would cause internal errors. */
+        Py_INCREF(input);
+        return input;
+    }
+
     if (strcmp(form, "NFC") == 0)
         return nfc_nfkc(input, 0);
     if (strcmp(form, "NFKC") == 0)