Fixes #566167

git-svn-id: http://svn.zope.org/repos/main/zc.buildout/trunk@120917 62d5b8a3-27da-0310-9561-8e5933582275

src/zc/buildout/download.py

@@ -175,16 +175,19 @@ class Download(object):
         urllib._urlopener = url_opener
         handle, tmp_path = tempfile.mkstemp(prefix='buildout-')
         try:
-            try:
-                tmp_path, headers = urllib.urlretrieve(url, tmp_path)
-                if not check_md5sum(tmp_path, md5sum):
-                    raise ChecksumError(
-                        'MD5 checksum mismatch downloading %r' % url)
-            finally:
-                os.close(handle)
-        except:
+            tmp_path, headers = urllib.urlretrieve(url, tmp_path)
+            if not check_md5sum(tmp_path, md5sum):
+                raise ChecksumError(
+                    'MD5 checksum mismatch downloading %r' % url)
+        except IOError, e:
+            os.remove(tmp_path)
+            raise zc.buildout.UserError("Error downloading extends for URL "
+                              "%s: %r" % (url, e[1:3]))
+        except Exception, e:
             os.remove(tmp_path)
             raise
+        finally:
+            os.close(handle)
 
         if path:
             shutil.move(tmp_path, path)

src/zc/buildout/download.txt

@@ -254,6 +254,13 @@ ChecksumError: MD5 checksum mismatch downloading 'http://localhost/foo.txt'
 
 >>> remove(path)
 
+If the file is completely missing it should notify the user of the error:
+
+>>> download(server_url+'bar.txt')
+Traceback (most recent call last):
+UserError: Error downloading extends for URL http://localhost/bar.txt: (404, 'Not Found')
+>>> ls(cache)
+
 Finally, let's see what happens if the download cache to be used doesn't exist
 as a directory in the file system yet: