Merge pull request #42374 from rails/backport-42316-42341

Backport #42316 and #42341 to 6-1-stable
rails · Jun 3, 2021 · 519b551 · 519b551
2 parents d83a318 + 17a4a0c
commit 519b551
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Showing 3 changed files with 19 additions and 6 deletions.
diff --git 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.

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
@@ -20,14 +20,18 @@ def convert
           end
 
           formatted_string =
-            if rounded_number.nan? || rounded_number.infinite? || rounded_number == rounded_number.to_i
-              "%00.#{precision}f" % rounded_number
-            else
+            if rounded_number.finite?
               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
+            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
@@ -207,6 +207,8 @@ 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)
+          assert_equal "-Inf", number_helper.number_to_rounded(-Float::INFINITY, precision: 0, significant: true)
         end
       end