Binary package hint: libgtk2-ruby
In Ubuntu 9.10 with the version of libgtk2-ruby from the repositories (0.19.0), new threads cause the Gtk main loop to freeze. As an example, the following code will never produce any output:
===== Impact =====
I don't know which program available directly within Ubuntu is written in Ruby-GTK+, but those which do and which are using the Ruby Thread class are broken, and of course developing such a program is broken too.
The fix is available in ruby-gnome2 since version 0.19.2 and was introduced through SVN revisions 3692[1] and 3694[2]. Both are within the attachment "ruby-gnome2-gtk-thread-patch.debdiff" in comment #1.
[1] http://ruby-gnome2.svn.sourceforge.net/viewvc/ruby-gnome2?view=rev&revision=3692
[2] http://ruby-gnome2.svn.sourceforge.net/viewvc/ruby-gnome2?view=rev&revision=3694
TEST CASE:
require 'gtk2'
Thread.new do
sleep 1 # Look busy
exit # Finished, exit
end
# Main loop
loop do
# Process all currently pending events
Gtk.main_iteration while Gtk.events_pending?
print '.'
end
However, when the latest version of the bindings is installed (0.19.3) the program works as expected, filling the screen with dots.
TEST CASE 2:
Here is another example for reproducing this bug:
require "gtk2"
include Gtk, GLib
# Create widgets
window = Window.new
vbox = VBox.new(false, 2)
button = Button.new("Run Thread")
progress = ProgressBar.new
# Pack widgets
window.add(vbox)
vbox.add(button)
vbox.add(progress)
# Set default window size
window.default_width = 120
window.default_height = 50
window.show_all
# Connect signals
button.signal_connect("clicked") do
Thread.new do
puts "Thread started!"
loop do
progress.pulse
sleep 1
end
end
end
window.signal_connect("destroy") { main_quit }
# Show all and run
main # start the GTK+ main loop
The test program shows a window with a button and a progress bar. Clicking the button will execute a Ruby Thread object, and the GUI visual elements/the GTK+ main loop will remain freezed.
REGRESSION:
The following applications use libgtk2-ruby and threads: fantasdic-1.0beta7 geekast-0.1.3 kazehakase-0.5.8 mhc-0.25.1+20090120 rbbr-0.6.0 xnetcardconfig-0.2.1
The example in the bug description is supposed to print dots, and instead it doesn't.
This problem is also reported at:
http://sourceforge.net/mailarchive/forum.php?thread_name=dc3bf8581001120746kb5da118udd0a74439cc4dcd9%40mail.gmail.com&forum_name=ruby-gnome2-devel-en
I attach a patch (debdiff) for the package which fixes the use of Thread objects inside GTK+/GLib main loops. It worked fine for me. The patch includes the two patches from Ruby-GNOME2 0.19.2.