jruby 9.3 fails to execute expressions

[ubuntuegor]

Steps to reproduce the behavior

1. Install jruby 9.3 (e.g., 9.3.15.0)
2. Try to execute an expression using the '-e' command line switch: ./bin/jruby -e 'print "hi"'

Expected vs. actual behavior

Expected:

Actual:

Additional information

The "expected" screenshot depicts jruby that was installed after reverting this commit: f661b64

[mislav]

Hi, thanks for reporting. Could you also look into which version of jruby-launcher you have installed, and report that here? Optionally, could you try upgrading jruby-launcher?

/cc @headius #2517

[ubuntuegor]

Sure.

~ % gem info jruby-launcher  
2025-07-29T12:43:21.545+03:00 [main] WARN FilenoUtil : Native subprocess control requires open access to the JDK IO subsystem
Pass '--add-opens java.base/sun.nio.ch=ALL-UNNAMED --add-opens java.base/java.io=ALL-UNNAMED' to enable.

*** LOCAL GEMS ***

jruby-launcher (2.0.2)
    Platform: java
    Authors: Nick Sieger, Vladimir Sizikov
    Homepage: http://jruby.org
    Installed at: /Users/egor.kukoverov/.rbenv/versions/jruby-9.3.15.0/lib/ruby/gems/shared

    Native launcher for JRuby
~ % gem update jruby-launcher
2025-07-29T12:43:24.818+03:00 [main] WARN FilenoUtil : Native subprocess control requires open access to the JDK IO subsystem
Pass '--add-opens java.base/sun.nio.ch=ALL-UNNAMED --add-opens java.base/java.io=ALL-UNNAMED' to enable.
Updating installed gems
Nothing to update

[chadlwilson]

Interesting. Some expressions not involving stdout/stderr seem to work fine, but it seems like something is interfering with stdout/stderr, as even ruby -e 'Java::JavaLang::System.out.println "hi"' doesn't work correctly. Going back to jruby-launcher 1.1.19 addresses the issue as well.

It seems like without the rm bin/jruby.sh that was there earlier, the gem install of jruby-launcher cannot/does not override an "old"/existing bin/jruby.sh script that came from the jruby tarball and instead puts the "new" script at jruby.sh.bak ... which seems the opposite of what should happen.

Perhaps it's confused because the binstub is not coming from an existing gem. I dunno. Nevertheless, this old jruby.sh script seems to cause the problem(s). Presumably related to jruby/jruby-launcher#48

Not a valid workaround

• Uninstalling jruby-launcher

Seems to be a valid workaround

• manually removing bin/jruby.sh from the install (without reinstalling jruby-launcher 2.0.2)
• manually removing bin/jruby.sh from the install (while reinstalling jruby-launcher 2.0.2)
• force installing jruby-launcher 1.1.19 (brings a different jruby binary which possibly ignores jruby.sh I guess?)

[mislav]

@chadlwilson Thanks a lot for the extra context and insight! Do you think this should be reported to the jruby-launcher repo?

@ubuntuegor Is that what happened in your installation too, that you ended up with bin/ruby.sh.bak? You can verify that by inspecting the contents of your ./jruby-bad/bin directory

[ubuntuegor]

Yes, there is a bin/jruby.sh.bak file both in jruby-bad and jruby-good.

[chadlwilson]

@mislav Im not sure if the issue can be worked around in jruby-launcher, but adding back the script removal here doesn't seem desirable. Not sure what the true root cause is, might need a bit more digging.

If it doesn't affect JRuby 9.4, and my wild theory is correct, possibly it's because rubygems changed the binstubs override behaviour with those bak files in the version that is bundled with 9.4, but which is problematic in the rubygems bundled with 9.3?

I presume the earlier removal of the jruby.sh might have been a workaround for something similar., but there are a lot of combinations of JRuby, launcher, platform and ruby-build that now need to work together in some fashion :(

[mislav]

Okay, since only JRuby 9.3 is affected, and since JRuby 9.3 is EOL and won't ever receive a fix for this, I've opted to apply a workaround in ruby-build. When installing JRuby 9.3, ruby-build will only ever install jruby-launcher v1.x but never jruby-launcher v2 or above.

BTW, there is a lengthy discussion about improving the jruby-launcher situation in ruby-build going forward: #2545

[chadlwilson]

Okay, since only JRuby 9.3 is affected, and since JRuby 9.3 is EOL and won't ever receive a fix for this, I've opted to apply a workaround in ruby-build. When installing JRuby 9.3, ruby-build will only ever install jruby-launcher v1.x but never jruby-launcher v2 or above.

OK. That does somewhat assume that the problem is with JRuby 9.3 in a way that cannot be addressed in jruby-launcher I suppose. I don't really know whether the intent was for everyone to be able to get to jruby-launcher v2+ to make support easier even for EOL JRubies, or whether it is only really "targetted" to work on newer JRuby versions.

BTW, there is a lengthy discussion about improving the jruby-launcher situation in ruby-build going forward: #2545

Yup, I saw that discussion and considered that this issue here might eventually be somewhat moot.

[headius]

Sorry I didn't jump into this sooner. You've largely figured out the problem but here's a bit more context...

https://github.com/jruby/jruby/blob/jruby-9.3/bin/jruby.sh

The jruby.sh for JRuby 9.3 is a very old version that is only minimally functional. The new jruby.sh that ships with 9.4.x and 10.x releases was not available until JRuby 9.4.0.0 after work by @mrnoname1000 in jruby/jruby#7024.

The recent changes to jruby-launcher were designed to avoid duplicating functionality between that codebase and jruby.sh, so it now just does the equivalent of exec /bin/sh bin/jruby.sh. Unfortunately when using that "skinny" launcher with JRuby 9.3, it's picking up the now very old and barely functional jruby.sh.

FWIW I have considered moving jruby.sh fully into the launcher project, so it can always be upgraded via RubyGems. Users would be able to get the newest command-line features without us re-releasing JRuby, and it would avoid cases like this (although we still wouldn't be testing on very old releases).

As y'all also mentioned, JRuby 9.3.x is EOL and we have no plans to update the shell script or do further releases in OSS.

Users that have a critical dependency on JRuby 9.3 (as well as anyone requiring expert help with JRuby upgrades, issues, or features) may be interested in the commercial support options from Headius Enterprises.

The workaround of either avoiding installing jruby-launcher (only needed on non-Linux unixes) or installing an older version (which will have reduced but equivalent functionality to the 9.3 jruby.bash both seem like fine alternatives for continuing support in ruby-build et al.

[mislav]

Thanks @chadlwilson for debug information and @headius for extra context. For now I've merged a simple workaround, which is installing jruby-launcher 1.x for JRuby 9.3. It does the trick for me locally, so let's hope it also helps other folks.