From 81175fb98a089d3b0b70a8ff8bf82a70556a3ff0 Mon Sep 17 00:00:00 2001
From: Mike Dalessio <mike.dalessio@gmail.com>
Date: Wed, 25 Aug 2021 08:16:27 -0400
Subject: [PATCH] Fix number_to_currency regression in handling "-0.0"

simplifying the method along the way.

This regressed in #42581 and is related to prior work in #39350 and #37865.
---
 .../number_to_currency_converter.rb           | 22 +++++++++----------
 activesupport/test/number_helper_test.rb      |  2 ++
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb b/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
index 4d0f9bd437..241ec903be 100644
--- a/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
@@ -8,23 +8,21 @@ module ActiveSupport
       self.namespace = :currency
 
       def convert
-        number = self.number.to_s.strip
         format = options[:format]
 
-        if number.sub!(/^-/, "")
-          number_f = number.to_f.abs
-          if number_f == 0.0
-            # likely an alternate input format that failed to parse.
-            # see https://github.com/rails/rails/pull/39350
-            format = options[:negative_format]
-          else
-            number_f *= 10**options[:precision]
-            format = options[:negative_format] if number_f >= 0.5
+        number_f = valid_float?
+        if number_f
+          if number_f.negative?
+            number_f = number_f.abs
+            format = options[:negative_format] if (number_f * 10**options[:precision]) >= 0.5
           end
+          number_s = NumberToRoundedConverter.convert(number_f, options)
+        else
+          number_s = number.to_s.strip
+          format = options[:negative_format] if number_s.sub!(/^-/, "")
         end
 
-        rounded_number = NumberToRoundedConverter.convert(number, options)
-        format.gsub("%n", rounded_number).gsub("%u", options[:unit])
+        format.gsub("%n", number_s).gsub("%u", options[:unit])
       end
 
       private
diff --git a/activesupport/test/number_helper_test.rb b/activesupport/test/number_helper_test.rb
index dcda16eb98..acb6f991c6 100644
--- a/activesupport/test/number_helper_test.rb
+++ b/activesupport/test/number_helper_test.rb
@@ -88,6 +88,8 @@ module ActiveSupport
           assert_equal("-$1,11", number_helper.number_to_currency("-1,11"))
           assert_equal("-$0,11", number_helper.number_to_currency("-0,11"))
           assert_equal("-$,11", number_helper.number_to_currency("-,11"))
+          assert_equal("$0.00", number_helper.number_to_currency(-0.0))
+          assert_equal("$0.00", number_helper.number_to_currency("-0.0"))
         end
       end