[pypy-commit] pypy release-2.2.x: avoid a fail attempt to copy nothing to a nullptr buffer

[pjenvey]

Author: Philip Jenvey <pjenvey at underboss.org>
Branch: release-2.2.x
Changeset: r68312:87aa9de10f9c
Date: 2013-11-15 11:44 -0800
http://bitbucket.org/pypy/pypy/changeset/87aa9de10f9c/

Log:	avoid a fail attempt to copy nothing to a nullptr buffer (grafted
	from 8d0da723fb85a16a3c850f2d7ed6d98b967cb6e2)

diff --git a/pypy/module/array/interp_array.py b/pypy/module/array/interp_array.py
--- a/pypy/module/array/interp_array.py
+++ b/pypy/module/array/interp_array.py
@@ -236,6 +236,8 @@
             raise OperationError(self.space.w_ValueError, self.space.wrap(msg))
         oldlen = self.len
         new = len(s) / self.itemsize
+        if not new:
+            return
         self.setlen(oldlen + new)
         cbuf = self._charbuf_start()
         copy_string_to_raw(llstr(s), rffi.ptradd(cbuf, oldlen * self.itemsize), 0, len(s))
diff --git a/pypy/module/array/test/test_array.py b/pypy/module/array/test/test_array.py
--- a/pypy/module/array/test/test_array.py
+++ b/pypy/module/array/test/test_array.py
@@ -171,6 +171,9 @@
         a = self.array('c')
         a.fromstring('Hi!')
         assert a[0] == 'H' and a[1] == 'i' and a[2] == '!' and len(a) == 3
+        a = self.array('c')
+        a.fromstring('')
+        assert not len(a)
 
         for t in 'bBhHiIlLfd':
             a = self.array(t)