Bug #11716: Truncation error in Time xmlschema with fraction_digits.

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 2.2.1p85 (2015-02-26 revision 49769) [x86_64-linux]
• Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN

[niroyb (Nick R)]

It looks like xmlschema with the fraction_digits parameter truncates the fractional second part.
Sometimes it truncates too much.
ex : 1447961542.26 with 2 fraction digits gives 1447961542.25 instead of 1447961542.26
Could be due to floating point representation. But tests seem to indicate otherwise.

$ irb $ require 'time' => true $ Time.at(1447961542.26).xmlschema(2) => "2015-11-19T11:32:22.25-08:00" $ Time.at(1447961542.269).xmlschema(2) => "2015-11-19T11:32:22.26-08:00" $ Time.at(1447961542.259).xmlschema(2) => "2015-11-19T11:32:22.25-08:00" $ Time.at(1447961542.25).xmlschema(2) => "2015-11-19T11:32:22.25-08:00" $ 1447961542.26*100.floor => 144796154226.0

[akr (Akira Tanaka)]

• Status changed from Open to Rejected

It's because 1447961542.26 is actually 1447961542.2599999904632568359375.

% ruby -e 'p "%.1000g" % 1447961542.26'
"1447961542.2599999904632568359375"

If 1447961542.26 is exactly given as rational, xmlschema(2) generates ".26" as the fractional part.

% ruby -rtime -e 'p Time.at(1447961542.26).xmlschema(2)'
"2015-11-20T04:32:22.25+09:00"
% ruby -rtime -e 'p Time.at(1447961542.26r).xmlschema(2)'
"2015-11-20T04:32:22.26+09:00"