From: Tanaka Akira <akr@...>
Date: 2010-04-11T09:27:49+09:00
Subject: [ruby-core:29426] rdoc --no-force-update problem on ext4 filesystem

rdoc --no-force-update doesn't work on a filesystem which have subsecond
timestamp.

I found rdoc --no-force-update doesn't work as follows on one of my machines.

  % rm -rf z
  % ../bin/rdoc --no-force-update --op z lib/base64.rb
  Parsing sources...
  100% [ 1/ 1]  lib/base64.rb

  Generating Darkfish...

  Files:         1
  Classes:       0 (    0 undocumented)
  Constants:     0 (    0 undocumented)
  Modules:       1 (    0 undocumented)
  Methods:       6 (    0 undocumented)
  100.00% documented

  Elapsed: 0.1s
  % ../bin/rdoc --no-force-update --op z lib/base64.rb
  Parsing sources...
  100% [ 1/ 1]  lib/base64.rb

  Generating Darkfish...

  Files:         1
  Classes:       0 (    0 undocumented)
  Constants:     0 (    0 undocumented)
  Modules:       1 (    0 undocumented)
  Methods:       6 (    0 undocumented)
  100.00% documented

  Elapsed: 0.1s

I found that this is caused by the timestamp has nano second resolution.
The filesystem is ext4.

  % ./ruby -rtime -e 'p File.mtime("lib/base64.rb").iso8601(9)'
  "2010-04-11T08:03:30.365903177+09:00"

created.rid contains only second.

  % cat z/created.rid
  Sun, 11 Apr 2010 09:11:13 +0900
  lib/base64.rb   Sun, 11 Apr 2010 08:03:30 +0900

So, lib/base64.rb is always considered as newer than the time in
created.rid.

  % ./ruby -v
  ruby 1.9.2dev (2010-04-11 trunk 27288) [x86_64-linux]
-- 
Tanaka Akira