Validate unescaped `%` chars in PO files

2 files changed, 36 insertions, 3 deletions

diff --git a/lib/gitlab/i18n/po_linter.rb b/lib/gitlab/i18n/po_linter.rb
index c3b1fe582af..2e02787a4f4 100644
--- a/lib/gitlab/i18n/po_linter.rb
+++ b/lib/gitlab/i18n/po_linter.rb
@@ -63,10 +63,25 @@ module Gitlab
         validate_variables(errors, entry)
         validate_newlines(errors, entry)
         validate_number_of_plurals(errors, entry)
+        validate_unescaped_chars(errors, entry)
 
         errors
       end
 
+      def validate_unescaped_chars(errors, entry)
+        if entry.msgid_contains_unescaped_chars?
+          errors << 'contains unescaped `%`, escape it using `%%`'
+        end
+
+        if entry.plural_id_contains_unescaped_chars?
+          errors << 'plural id contains unescaped `%`, escape it using `%%`'
+        end
+
+        if entry.translations_contain_unescaped_chars?
+          errors << 'translation contains unescaped `%`, escape it using `%%`'
+        end
+      end
+
       def validate_number_of_plurals(errors, entry)
         return unless metadata_entry&.expected_plurals
         return unless entry.translated?
@@ -79,15 +94,15 @@ module Gitlab
 
       def validate_newlines(errors, entry)
         if entry.msgid_contains_newlines?
-          errors << "is defined over multiple lines, this breaks some tooling."
+          errors << 'is defined over multiple lines, this breaks some tooling.'
         end
 
         if entry.plural_id_contains_newlines?
-          errors << "plural is defined over multiple lines, this breaks some tooling."
+          errors << 'plural is defined over multiple lines, this breaks some tooling.'
         end
 
         if entry.translations_contain_newlines?
-          errors << "has translations defined over multiple lines, this breaks some tooling."
+          errors << 'has translations defined over multiple lines, this breaks some tooling.'
         end
       end
 
diff --git a/lib/gitlab/i18n/translation_entry.rb b/lib/gitlab/i18n/translation_entry.rb
index 8d4fec0decd..e6c95afca7e 100644
--- a/lib/gitlab/i18n/translation_entry.rb
+++ b/lib/gitlab/i18n/translation_entry.rb
@@ -1,6 +1,8 @@
 module Gitlab
   module I18n
     class TranslationEntry
+      PERCENT_REGEX = /(?:^|[^%])%(?!{\w*}|[a-z%])/.freeze
+
       attr_reader :nplurals, :entry_data
 
       def initialize(entry_data, nplurals)
@@ -64,6 +66,22 @@ module Gitlab
         all_translations.any? { |translation| translation.is_a?(Array) }
       end
 
+      def msgid_contains_unescaped_chars?
+        contains_unescaped_chars?(msgid)
+      end
+
+      def plural_id_contains_unescaped_chars?
+        contains_unescaped_chars?(plural_id)
+      end
+
+      def translations_contain_unescaped_chars?
+        all_translations.any? { |translation| contains_unescaped_chars?(translation) }
+      end
+
+      def contains_unescaped_chars?(string)
+        string =~ PERCENT_REGEX
+      end
+
       private
 
       def translation_keys