From: Luis Lavena <luislavena@...>
Date: 2011-06-22T00:44:25+09:00
Subject: [ruby-core:37262] Re: 1.8.7 release next month

On Sun, Jun 19, 2011 at 10:55 PM, Hidetoshi NAGAI
<nagai@ai.kyutech.ac.jp> wrote:
>
> I can't generate the problem.
> "ruby -r tk -e 'p Tk.tk_call("info", "library")'" prints the value of
> TCL_LIBRARY environment variable.
> Is the env var really exported?
> When not do "export TCL_LIBRARY" on the terminal, the value of the env
> var has no effect.

Hello,

I'll try to clarify my previous statement.

Tcl/Tk libs are not placed in the default directory ($ruby/lib) but
instead in a custom directory ($ruby/lib/tcltk)

Because of it, attempting to require 'tk' fails because is unable to
find init.tcl anywhere in the whole path options for lib.

What we did, as this patch shows:

https://github.com/oneclick/rubyinstaller/blob/master/resources/patches/tk/0002-Use-Tcl-Tk-from-different-directory.diff

Is set TCL_LIBRARY before loading the C extension.

This works perfectly against 1.9.3 (trunk), but fails on 1.8.7

TCL_LIBRARY is set inside Ruby and can't be set/exported from outside
ruby code because that will pollute the environment.

Your example works on trunk:

V:\sandbox>ruby -v
ruby 1.9.3dev (2011-06-21 trunk 32188) [i386-mingw32]

V:\sandbox>ruby -r tk -e 'p Tk.tk_call("info", "library")'"
"V:/sandbox/ruby19_mingw/lib/tcltk/tcl8.5"

But fails with ruby_1_8_7 branch:

V:\sandbox>ruby -v
ruby 1.8.7 (2011-06-16 patchlevel 348) [i386-mingw32]

V:\sandbox>ruby -r tk -e 'p Tk.tk_call("info", "library")'"
V:/sandbox/ruby18_mingw/lib/ruby/1.8/tk.rb:1132:in `initialize': Can't
find a usable init.tcl in the following directories:  (RuntimeError)
    V:/sandbox/ruby18_mingw/lib/tcl8.5
V:/sandbox/ruby18_mingw/lib/tcl8.5 V:/sandbox/lib/tcl8.5
V:/sandbox/ruby18_mingw/library V:/sandbox/library
V:/sandbox/tcl8.5.9/library V:/tcl8.5.9/library



This probably means that Tcl wasn't installed properly.
        from V:/sandbox/ruby18_mingw/lib/ruby/1.8/tk.rb:1132:in `new'
        from V:/sandbox/ruby18_mingw/lib/ruby/1.8/tk.rb:1132

===

As you can see, it is ignoring TCL_LIBRARY value set from inside Ruby itself.

Now, setting it from outside the process works:

V:\sandbox>set TCL_LIBRARY
Environment variable TCL_LIBRARY not defined

V:\sandbox>SET TCL_LIBRARY=V:\sandbox\ruby18_mingw\lib\tcltk\tcl8.5

V:\sandbox>ruby -r tk -e 'p Tk.tk_call("info", "library")'"
"V:\\sandbox\\ruby18_mingw\\lib\\tcltk\\tcl8.5"

===

Which could indicate another problem with TCL_LIBRARY?

-- 
Luis Lavena
AREA 17
-
Perfection in design is achieved not when there is nothing more to add,
but rather when there is nothing more to take away.
Antoine de Saint-Exup�ry