Parse ISO8601 datetimes without Time.parse

Author: hsbt

lib/rubygems/yaml_serializer.rb

@@ -271,10 +271,19 @@ def coerce(val)
           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})(?: (\d{2}):(\d{2}):(\d{2})(?:\.(\d+))?\s*(Z|[+-]\d{2}:\d{2}))?\z/.match(val)
           begin
-            Time.parse(val)
+            year, mon, mday = $1.to_i, $2.to_i, $3.to_i
+            hour, min, sec = ($4 || 0).to_i, ($5 || 0).to_i, ($6 || 0).to_i
+            nsec = $7 ? $7.ljust(9, "0")[0, 9].to_i : 0
+            tz = $8
+            t = Time.utc(year, mon, mday, hour, min, sec, Rational(nsec, 1000))
+            if tz && tz != "Z"
+              sign = tz[0] == "-" ? 1 : -1
+              tz_hour, tz_min = tz[1..].split(":").map(&:to_i)
+              t += sign * (tz_hour * 3600 + tz_min * 60)
+            end
+            t
           rescue ArgumentError
             val
           end