1 files changed, 26 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/i18n_interpolation_deprecation.rb b/activerecord/lib/active_record/i18n_interpolation_deprecation.rb
new file mode 100644
index 0000000000..cd634e1b8d
--- /dev/null
+++ b/activerecord/lib/active_record/i18n_interpolation_deprecation.rb
@@ -0,0 +1,26 @@
+# Deprecates the use of the former message interpolation syntax in activerecord
+# as in "must have %d characters". The new syntax uses explicit variable names
+# as in "{{value}} must have {{count}} characters".
+
+require 'i18n/backend/simple'
+module I18n
+  module Backend
+    class Simple
+      DEPRECATED_INTERPOLATORS = { '%d' => '{{count}}', '%s' => '{{value}}' }
+
+      protected
+        def interpolate_with_deprecated_syntax(locale, string, values = {})
+          return string unless string.is_a?(String)
+
+          string = string.gsub(/%d|%s/) do |s|
+            instead = DEPRECATED_INTERPOLATORS[s]
+            ActiveSupport::Deprecation.warn "using #{s} in messages is deprecated; use #{instead} instead."
+            instead
+          end
+
+          interpolate_without_deprecated_syntax(locale, string, values)
+        end
+        alias_method_chain :interpolate, :deprecated_syntax
+    end
+  end
+end
+\ No newline at end of file