From: akr@...
Date: 2015-11-19T22:55:20+00:00
Subject: [ruby-core:71592] [Ruby trunk - Bug #11716] [Rejected] Truncation error in Time xmlschema with fraction_digits.

Issue #11716 has been updated by 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"
```



----------------------------------------
Bug #11716: Truncation error in Time xmlschema with fraction_digits.
https://bugs.ruby-lang.org/issues/11716#change-54975

* Author: Nick R
* Status: Rejected
* Priority: Normal
* Assignee: 
* 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
----------------------------------------
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
`



-- 
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