From 942267b52abfa5b0c5312831002143987b2dbeb8 Mon Sep 17 00:00:00 2001
From: Federico Aldunate <federico.aldunatec@gmail.com>
Date: Fri, 28 May 2021 20:40:49 -0300
Subject: [PATCH 1/3] Use BigDecimal compatible operation in
 NumberToRoundedConverter

---
 .../number_helper/number_to_rounded_converter.rb  | 15 ++++++++++-----
 activesupport/test/number_helper_test.rb          |  1 +
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb b/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
index 8cf412088d6ac..6bd1e1bb66e2f 100644
--- a/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
@@ -20,14 +20,19 @@ def convert
           end
 
           formatted_string =
-            if rounded_number.nan? || rounded_number.infinite? || rounded_number == rounded_number.to_i
-              "%00.#{precision}f" % rounded_number
+            if rounded_number.nan?
+              "NaN"
+            elsif rounded_number.infinite?
+              "Inf"
             else
               s = rounded_number.to_s("F")
-              s << "0" * precision
               a, b = s.split(".", 2)
-              a << "."
-              a << b[0, precision]
+              if precision != 0
+                b << "0" * precision
+                a << "."
+                a << b[0, precision]
+              end
+              a
             end
         else
           formatted_string = rounded_number
diff --git a/activesupport/test/number_helper_test.rb b/activesupport/test/number_helper_test.rb
index 579ba73ede255..ca9a02f536451 100644
--- a/activesupport/test/number_helper_test.rb
+++ b/activesupport/test/number_helper_test.rb
@@ -207,6 +207,7 @@ def test_to_rounded_with_significant_digits
           assert_equal "9775.0000000000000000", number_helper.number_to_rounded("9775", precision: 20, significant: true)
           assert_equal "9775." + "0" * 96, number_helper.number_to_rounded("9775", precision: 100, significant: true)
           assert_equal("97.7", number_helper.number_to_rounded(Rational(9772, 100), precision: 3, significant: true))
+          assert_equal "28729870200000000000000", number_helper.number_to_rounded(0.287298702e23.to_d, precision: 0, significant: true)
         end
       end
 

From 5608ba8e668a5571cd25d196ca6e3a73412e2b3f Mon Sep 17 00:00:00 2001
From: Zachary Scott <zzakscott@gmail.com>
Date: Tue, 1 Jun 2021 16:08:21 +0900
Subject: [PATCH 2/3] NumberToRoundedConverter should handle -Float::INFINITY

cc https://github.com/rails/rails/pull/42316#issuecomment-851606043
---
 .../number_helper/number_to_rounded_converter.rb         | 9 ++++-----
 activesupport/test/number_helper_test.rb                 | 1 +
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb b/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
index 6bd1e1bb66e2f..f48a5158c3362 100644
--- a/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
@@ -20,11 +20,7 @@ def convert
           end
 
           formatted_string =
-            if rounded_number.nan?
-              "NaN"
-            elsif rounded_number.infinite?
-              "Inf"
-            else
+            if rounded_number.finite?
               s = rounded_number.to_s("F")
               a, b = s.split(".", 2)
               if precision != 0
@@ -33,6 +29,9 @@ def convert
                 a << b[0, precision]
               end
               a
+            else
+              # Infinity/NaN
+              "%f" % rounded_number
             end
         else
           formatted_string = rounded_number
diff --git a/activesupport/test/number_helper_test.rb b/activesupport/test/number_helper_test.rb
index ca9a02f536451..9bdec994b74d3 100644
--- a/activesupport/test/number_helper_test.rb
+++ b/activesupport/test/number_helper_test.rb
@@ -208,6 +208,7 @@ def test_to_rounded_with_significant_digits
           assert_equal "9775." + "0" * 96, number_helper.number_to_rounded("9775", precision: 100, significant: true)
           assert_equal("97.7", number_helper.number_to_rounded(Rational(9772, 100), precision: 3, significant: true))
           assert_equal "28729870200000000000000", number_helper.number_to_rounded(0.287298702e23.to_d, precision: 0, significant: true)
+          assert_equal "-Inf", number_helper.number_to_rounded(-Float::INFINITY, precision: 0, significant: true)
         end
       end
 

From 17a4a0c5b5d5bd1dc8a1796b097db0c72b0f99b4 Mon Sep 17 00:00:00 2001
From: Andrew White <andrew.white@unboxed.co>
Date: Thu, 3 Jun 2021 15:27:56 +0100
Subject: [PATCH 3/3] Add CHANGELOG entry for #42316 and #42341

---
 activesupport/CHANGELOG.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 5255ee4fbce3f..89893579f7a39 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,10 @@
+*   Fix bug in `number_with_precision` when using large `BigDecimal` values.
+
+    Fixes #42302.
+
+    *Federico Aldunate*, *Zachary Scott*
+
+
 ## Rails 6.1.3.2 (May 05, 2021) ##
 
 *   No changes.