Here is quote from the article of Ruby Inside.
(http://www.rubyinside.com/ruby-1-9-2-p290-released-the-lowdown-on-rubys-latest-production-release-5145.html) For more change, please refer:
http://svn.ruby-lang.org/repos/ruby/tags/v1_9_2_290/ChangeLog
What's Changed From p180 to p290?
Quite a lot got changed in terms of the numbers. 132 files were
tweaked with a total of 3505 lines added and 788 taken away.
A selection of the fixes:
* require 'date'; Date.new === nil throws an undefined method error for
coerce on p180 - this has now been fixed
* The Thread.kill segfaults when the object to be killed isn't a thread bug
has been resolved.
* Tweaks to reduce segmentation faults when using zlib on x86-64 Darwin
(OS X) - always good
* Modification to prevent random number sequence repetition on forked child
processes in SecureRandom
* Fix to io system to resolve a Windows-only bug where characters are being
read incorrectly due to ASCII not being treated as 7 bit
* A tweak to Psych (the YAML parser) to plug a memory leak
* Load paths are now always expanded by rb_et_expanded_load_path (I think
this might yield a performance gain?)
* Fixes to Psych's treatment and testing of string taint
* Prevention of temporary objects being garbage collected in some cases
* Fixes to resolve compilation problems with Visual C++ 2010
* A fix so that Tk's extconf.rb would run successfully
* Lots of Tk related fixes generally - I'm guessing Tk is very popular
amongst the core team, particularly in Japan, because it seems to be a
common release blocker.
* A fix to string parsing to resolve an obscure symbol-containing-newlines
parsing bug
=== 3.9.1 / ??
* Bug fixes
* Fix RDoc::Markup parser for a header followed by a non-text token. Issue
#56 by Adam Tait
* Fix RDoc::Markup::ToHtmlCrossref#gen_url for non-<tt>rdoc-ref</tt> links.
* Fix bug report URL when rdoc crashes.
=== 3.9 / 2011-07-30
* Minor enhancements
* RDoc::Parser::C now supports :doc: and :nodoc: for class comments
* Added the <tt>rdoc-ref:</tt> link scheme which links to a named reference.
<tt>rdoc-ref:</tt> can resolve references to classes, modules, methods,
files, etc. This can be used to create cross-generator named links unlike
the <tt>link:</tt> scheme which is dependent upon the exact file name.
Issue #53 by Simon Chiang
* Pulled RDoc::CrossReference out of RDoc::Markup::ToHtmlCrossref.
Cross-references can now be created easily for non-HTML formatters.
* Bug fixes
* `ri []` and other special methods now work properly. Issue #52 by
ddebernardy.
* `ri` now has space between class comments from multiple files.
* :stopdoc: no longer creates Object references. Issue #55 by Simon Chiang
* :nodoc: works on class aliases now. Issue #51 by Steven G. Harms
* Remove tokenizer restriction on header lengths for verbatim sections.
Issue #49 by trans
If it specified, it modify gemspec's dependency using update-gemspec.rb
Ruby script.
The goal is avoid to use patch for modifying depending version or gem's
name since gemspec files' content differ using rubygem's version.
* Derek Lamb's patch to avoid an uninitialised variable error.
* Diab Jarius's Solaris Studio 10 patch and his gfortran patch (with mods).
Note g77 is still the default if both it and gfortran are present.
* Rob's big Win32 patch (Nov 2010 version)
* IMPORTANT. Added in simplification of GNU fortran compilers
(g77, gfortran, g95, fort77) etc. suggested by Tim Jeness. I used his code
but made a slightly different implementaion introducing a 'Generic' 'GNU'
database entry to which others point.
This also superceded some of the above patches.
Hope this works!
* Removed places where .gcclibs() is added to the link line, this appears to
no loner be necessary. Routine left in there (but orphaned) just in case.
* Remove test boilerplate the reorganisation of dual-life modules in the perl
code made unnecessary.
* Remove Shell::Command - that module is now available in the Shell::Command
distribution on CPAN.
* do not avoid the clock_gettime call on GNU/Linux anymore, as EV
links against -lpthread anyways - as a result, EV might now take
advantage of fast userspace clock_gettime implementations,
but also links against -lrt.
* (libev) lots of event port bug workarounds.
* (libev) officially support files in I/O watchers.
* (libev) new function ev_feed_signal.
* fix documentation parts still refering to the 3.x API.
