Use block parameter rather than `$1` during `gsub!` so `ActiveSupport::SafeBuffer` values aren't mangled.

Fixes #15064

3 files changed, 13 insertions, 1 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 8d16898c80..68b327e0ad 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,12 @@
+*   Fixed an issue when using
+    `ActiveSupport::NumberHelper::NumberToDelimitedConverter` to
+    convert a value that is an `ActiveSupport::SafeBuffer` introduced
+    in 2da9d67.
+
+    For more info see #15064.
+
+    *Mark J. Titorenko*
+
 *   `TimeZone#parse` defaults the day of the month to '1' if any other date
     components are specified. This is more consistent with the behavior of
     `Time#parse`.
diff --git a/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb b/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb
index 6405afc9a6..d85cc086d7 100644
--- a/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb
@@ -13,7 +13,9 @@ module ActiveSupport
 
         def parts
           left, right = number.to_s.split('.')
-          left.gsub!(DELIMITED_REGEX) { "#{$1}#{options[:delimiter]}" }
+          left.gsub!(DELIMITED_REGEX) do |digit_to_delimit|
+            "#{digit_to_delimit}#{options[:delimiter]}"
+          end
           [left, right].compact
         end
     end
diff --git a/activesupport/test/number_helper_test.rb b/activesupport/test/number_helper_test.rb
index 9bdb92024e..b220fd4232 100644
--- a/activesupport/test/number_helper_test.rb
+++ b/activesupport/test/number_helper_test.rb
@@ -97,6 +97,7 @@ module ActiveSupport
           assert_equal("123,456,789.78901", number_helper.number_to_delimited(123456789.78901))
           assert_equal("0.78901", number_helper.number_to_delimited(0.78901))
           assert_equal("123,456.78", number_helper.number_to_delimited("123456.78"))
+          assert_equal("123,456.78", number_helper.number_to_delimited(ActiveSupport::SafeBuffer.new("123456.78")))
         end
       end