From 1425c52227045fac17764b426a90d1b4ac369ba0 Mon Sep 17 00:00:00 2001
From: Hiroshi SHIBATA <hsbt@ruby-lang.org>
Date: Mon, 9 Mar 2026 17:26:02 +0900
Subject: Parse ISO8601 datetimes without Time.parse

---
 lib/rubygems/yaml_serializer.rb | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/lib/rubygems/yaml_serializer.rb b/lib/rubygems/yaml_serializer.rb
index 28616cdfde..edc0133ce2 100644
--- a/lib/rubygems/yaml_serializer.rb
+++ b/lib/rubygems/yaml_serializer.rb
@@ -271,12 +271,16 @@ module Gem
           return Sequence.new if inner.empty?
           items = inner.split(/\s*,\s*/).reject(&:empty?).map {|e| Scalar.new(value: coerce(e)) }
           Sequence.new(items: items)
-        elsif /^\d{4}-\d{2}-\d{2}/.match?(val)
-          require "time"
+        elsif /\A\d{4}-\d{2}-\d{2}([ T]\d{2}:\d{2}:\d{2})?/.match?(val)
           begin
-            Time.parse(val)
+            Time.new(val)
           rescue ArgumentError
-            val
+            # date-only format like "2024-06-15" is not supported by Time.new
+            if /\A(\d{4})-(\d{2})-(\d{2})\z/.match(val)
+              Time.utc($1.to_i, $2.to_i, $3.to_i)
+            else
+              val
+            end
           end
         elsif /^-?\d+$/.match?(val)
           val.to_i
-- 
cgit v1.2.3