Bug #11984: DateTime.parse can parse invalid datetime string

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 2.2.4p230 (2015-12-16 revision 53155) [x86_64-linux] and ruby 2.0.0p645 (2015-04-13 revision 50299) [universal.x86_64-darwin15]
• Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN

[lanscene (jarry xu)]

It seems if you pass a string which begins with 2 alphabets and following is 7 numerics, it can be parsed as DateTime, as follows

irb(main):002:0> require 'time'
irb(main):008:0> dt0 = DateTime.parse('fg4534253dd')
=> #<DateTime: 4534-09-10T00:00:00+00:00 ((3377322j,0s,0n),+0s,2299161j)>
irb(main):009:0> dt0 = DateTime.parse('fg4534253')
=> #<DateTime: 4534-09-10T00:00:00+00:00 ((3377322j,0s,0n),+0s,2299161j)>
irb(main):010:0> DateTime.parse('gg1233234')
=> #<DateTime: 1233-08-22T00:00:00+00:00 ((2171645j,0s,0n),+0s,2299161j)>
irb(main):011:0> DateTime.parse('gg1233234dd')
=> #<DateTime: 1233-08-22T00:00:00+00:00 ((2171645j,0s,0n),+0s,2299161j)>

[long_long_float (kazuki niimi)]

Is it a specification? When you pass 'fg4534253dd' to DateTime#parse, parse_ddd is called. It doesn't parse from begin of string.
And document says DateTime#parse is not for validator.

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Rejected

This isn't a bug. DateTime.parse assume the string you are passing in has some date related information in it, and tries the best it can to find something. In this case, it guesses that the first four digits are the year and the last three are the day of the year. The non-digits in this case are ignored.

DateTime._parse('fg4534253dd')
# => {:year=>4534, :yday=>253}

DateTime._parse('4534253')
# => {:year=>4534, :yday=>253}