When polib raises an exception, re-raise it as a ParseError

so that:

1. The error message the user gets helps him/her resolve the problem
2. We don't show a 500 error to the user
3. We don't get a report in sentry

Related: https://sentry.int.transifex.com/developers/transifex/issues/25094/

openformats/formats/po.py

@@ -30,7 +30,11 @@ def parse(self, content, is_source=False):
         stringset = []
         self.is_source = is_source
         self.order_generator = itertools.count()
-        po = polib.pofile(content)
+        try:
+            po = polib.pofile(content)
+        except Exception, e:
+            raise ParseError("Error while validating PO file syntax: {}".
+                             format(e.message))
         self.only_values = False
         self.only_keys = False
         self.new_po = copy.copy(po)

openformats/tests/formats/po/test_po.py

@@ -1,12 +1,12 @@
 import unittest
 import itertools
 
-from openformats.strings import OpenString
+from openformats.exceptions import ParseError
 from openformats.formats.po import PoHandler
+from openformats.strings import OpenString
 from openformats.tests.formats.common import CommonFormatTestMixin
-from openformats.tests.utils.strings import (
-    strip_leading_spaces, generate_random_string
-)
+from openformats.tests.utils.strings import (strip_leading_spaces,
+                                             generate_random_string)
 
 
 class PoTestCase(CommonFormatTestMixin, unittest.TestCase):
@@ -462,3 +462,8 @@ def test_incomplete_plurals(self):
             u"Incomplete plural forms found on the entry with msgid `p1` "
             u"and msgid_plural `p2`."
         )
+
+    def test_invalid_po_raised_as_parseerror(self):
+        source = "blyargh"
+        with self.assertRaises(ParseError):
+            self.handler.parse(source)