[37607] Fix pluralization fallbacks (#9388)

Always use the :other key for falling back to locales, or return nil

to ensure the english pluralization keys are used

https://community.openproject.org/wp/37607

Gemfile.lock

@@ -27,7 +27,7 @@ GIT
 
 GIT
   remote: https://github.com/opf/openproject-translations.git
-  revision: ec6fbe6ef86f82e65f37adb17f37aa5addc17ac4
+  revision: b28dbe0bc4f347e79f34cd5b42cff2f03f2f7404
   branch: dev
   specs:
     openproject-translations (7.4.0)

spec/lib/i18n/pluralization_spec.rb

@@ -0,0 +1,76 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) 2012-2021 the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See docs/COPYRIGHT.rdoc for more details.
+#++
+
+require 'spec_helper'
+
+describe I18n, 'pluralization', type: :helper do
+
+  describe 'with slowenian language and the :two plural key missing' do
+    before do
+      I18n.locale = :sl
+      allow(I18n.backend)
+        .to(receive(:lookup))
+        .and_call_original
+
+      allow(I18n.backend)
+        .to(receive(:lookup))
+        .with(:sl, :label_x_projects, any_args)
+        .and_return({one: "1 projekt", other: "%{count} projektov", zero: "Brez projektov"})
+    end
+
+    it 'allows to pluralize without exceptions (Regression #37607)', :aggregate_failures do
+      expect(I18n.t(:label_x_projects, count: 0)).to eq 'Brez projektov'
+      expect(I18n.t(:label_x_projects, count: 1)).to eq '1 projekt'
+      expect(I18n.t(:label_x_projects, count: 2)).to eq '2 projektov'
+      expect(I18n.t(:label_x_projects, count: 10)).to eq '10 projektov'
+      expect(I18n.t(:label_x_projects, count: 20)).to eq '20 projektov'
+    end
+  end
+
+  describe 'with slowenian language and the :other plural key missing' do
+    before do
+      I18n.locale = :sl
+      allow(I18n.backend)
+        .to(receive(:lookup))
+        .and_call_original
+
+      allow(I18n.backend)
+        .to(receive(:lookup))
+        .with(:sl, :label_x_projects, any_args)
+        .and_return({one: "1 projekt", zero: "Brez projektov"})
+    end
+
+    it 'falls back to english translation (Regression #37607)', :aggregate_failures do
+      expect(I18n.t(:label_x_projects, count: 0)).to eq 'Brez projektov'
+      expect(I18n.t(:label_x_projects, count: 1)).to eq '1 projekt'
+      expect(I18n.t(:label_x_projects, count: 2)).to eq '2 projects'
+      expect(I18n.t(:label_x_projects, count: 10)).to eq '10 projects'
+      expect(I18n.t(:label_x_projects, count: 20)).to eq '20 projects'
+    end
+  end
+end