Support for translation components without translations

Once we're able to add new translations, it's not necessary to have one
existing, users can add new one.

Fixes #878
Signed-off-by: Michal Čihař <michal@cihar.com>

docs/changes.rst

@@ -16,6 +16,7 @@ Released on ? 2015.
 * Added support for generating contributor stats.
 * Site wide search can search only in one language.
 * Improve quality checks for Armenian.
+* Support for starting translation components without existing translations.
 
 weblate 2.4
 -----------

weblate/trans/models/subproject.py

@@ -1135,7 +1135,7 @@ class SubProject(models.Model, PercentMixin, URLMixin, PathMixin):
         '''
         Validates that there are no double language codes found in the files.
         '''
-        if len(matches) == 0:
+        if len(matches) == 0 and not self.can_add_new_language():
             raise ValidationError(_('The mask did not match any files!'))
         langs = set()
         translated_langs = set()

weblate/trans/tests/test_models.py

@@ -180,6 +180,14 @@ class RepoTestCase(TestCase):
             'po/*.po',
         )
 
+    def create_po_empty(self):
+        return self._create_subproject(
+            'po',
+            'po-empty/*.po',
+            new_base='po-empty/hello.pot',
+            new_lang='add',
+        )
+
     def create_po_mercurial(self):
         return self._create_subproject(
             'po',
@@ -352,7 +360,7 @@ class SubProjectTest(RepoTestCase):
     """
     SubProject object testing.
     """
-    def verify_subproject(self, project, translations, lang, units,
+    def verify_subproject(self, project, translations, lang=None, units=0,
                           unit='Hello, world!\n', fail=False):
         # Validation
         if fail:
@@ -368,12 +376,13 @@ class SubProjectTest(RepoTestCase):
         self.assertEqual(
             project.translation_set.count(), translations
         )
-        # Grab translation
-        translation = project.translation_set.get(language_code=lang)
-        # Count units in it
-        self.assertEqual(translation.unit_set.count(), units)
-        # Check whether unit exists
-        self.assertTrue(translation.unit_set.filter(source=unit).exists())
+        if lang is not None:
+            # Grab translation
+            translation = project.translation_set.get(language_code=lang)
+            # Count units in it
+            self.assertEqual(translation.unit_set.count(), units)
+            # Check whether unit exists
+            self.assertTrue(translation.unit_set.filter(source=unit).exists())
 
     def test_create(self):
         project = self.create_subproject()
@@ -478,6 +487,10 @@ class SubProjectTest(RepoTestCase):
         project = self.create_po_mercurial()
         self.verify_subproject(project, 3, 'cs', 4)
 
+    def test_create_po_empty(self):
+        project = self.create_po_empty()
+        self.verify_subproject(project, 0)
+
     def test_create_po_link(self):
         project = self.create_po_link()
         self.verify_subproject(project, 4, 'cs', 4)