NSIS - jruby fails to access environment variables - jruby

Question

I've made a NSIS script to create an installer for a Rails application.
The application uses JRuby and Java.
In the first section of the installer I set the environment variables: I add jruby\bin to PATH and I create JAVA_HOME variable, which points to Java\jre6.
!define JRubyBinPath "$PROGRAMFILES\${PRODUCT_PUBLISHER}\JRuby\jruby-1.6.3\bin"
Function SetEnvVars
# set JAVA_HOME
${EnvVarUpdate} $0 "JAVA_HOME" "A" "HKCU" "C:\Program Files\Java\jre6"
# add jruby to Path
${EnvVarUpdate} $0 "Path" "A" "HKLM" "${JRubyBinPath}"
FunctionEnd
Section "Pre" SEC01
Call SetEnvVars
...
SectionEnd
** All the paths are correct. **
In the second section of the installer, after packing all the application files and JRuby files, I initialize the database using the following commands:
Section "Installer" SEC02
...
SetOutPath $INSTDIR
nsExec::ExecToLog "jruby -S bundle exec rake db:create RAILS_ENV=production"
nsExec::ExecToLog "jruby -S bundle exec rake db:migrate RAILS_ENV=production"
nsExec::ExecToLog "jruby -S bundle exec rake db:seed RAILS_ENV=production"
...
SectionEnd
The problem is that when I run the installer on a clean Windows system, all the code executes correctly, except for the lines that contain commands using "jruby". I get no error in the installer window, it just won't execute those lines.
Anyway, if I manually run those commands in a console right after the installer finishes, everything works as expected.
From what I have seen so far, the problem is that the installer cannot access the environment variables until it finishes.
* What I have done so far to solve this problem is creating the main installer Installer.exe (here I pack all the files and I set the environment variables), and another executable Init.exe which initializes the database.
If I manually run these executables - first Installer.exe then Init.exe - the application installs correctly. But if I try to launch Init.exe from Installer.exe, it won't work.
However, if there would be a way to execute the "jruby" commands in a new/different thread than the one that sets the environment variables, I think the problem would be solved. But I still couldn't find the way to do that.
Thanks.

Answer 1

NSIS doesn't have any threading. Apparently not quite true—but in your own code, you don't get to use threads.
You may need to set PATH for the current process; I'm not familiar with ${EnvVarUpdate}, but looking at its script it doesn't seem to updates the variable in the current process. Try this:
${EnvVarUpdate} $0 PATH A HKLM "${JRubyBinPath}" # The line you already have
System::Call Kernel32::SetEnvironmentVariable(t"PATH",tr0)
Another note: you are hard-coding JRubyBinPath; are you sure you really want to do that?