NameError: (NameError) uninitialized constant Gem::Package from version 9.3.0.0

[Shahafgo]

Hi all,

Currently we use Jruby version: 9.2.20.0 and we would like to upgrade to the latest version (9.4.9.0) but I started to notice this problem from 9.3.0.0.

We have a code that initialize the scriptingContainer like with ruby script:

private static final String GEMS_HELPER = "gems_helper.rb";

public synchronized void init() {
      if (scriptingContainer == null) {
          LocalContextScope localContextScope = resolveLocalContextScope();
          ScriptingContainer scriptingContainerInstance = new ScriptingContainer(localContextScope,
                  LocalVariableBehavior.PERSISTENT);
          scriptingContainerInstance.setClassLoader(Thread.currentThread().getContextClassLoader());
          IRubyObject gemsHelperClass;
          try (InputStream is = scriptingContainerInstance.getClassLoader().getResourceAsStream(GEMS_HELPER)) {
              EmbedEvalUnit result = scriptingContainerInstance.parse(is, GEMS_HELPER);
              gemsHelperClass = result.run();
          } catch (Exception e) {
              throw new IllegalStateException("Could not initialize gems helper", e);
          }

          this.gemsHelper = scriptingContainerInstance.callMethod(gemsHelperClass, "new", Object.class);
          this.scriptingContainer = scriptingContainerInstance;
          log.info("Initialized {} successfully", getClass().getSimpleName());
      }
  }

Ruby script gems_helper.rb:

require 'rubygems'
require 'rubygems/package'

 def name_version_platform(gem_file_path)
      spec = Gem::Package.new(gem_file_path).spec
      spec.name + ',' + spec.version.to_s + ',' + (spec.platform.nil? ? 'unknown' : spec.platform.to_s)
end

From my java code I am trying to call to name_version_platform function

 public NameVersionPlatformTuple getGemNameVersionPlatform(File gemFile) {
        String result = call("name_version_platform", gemFile.getAbsolutePath());
        String[] nvp = result.split(",");
        return new NameVersionPlatformTuple(nvp[0], nvp[1], nvp[2]);
    }

private <T> T call(String method, Object... params) {
            //noinspection unchecked
            return (T) getScriptingContainer().callMethod(gemsHelper, method, params);
    }

When I call name_version_platform from multiple thread in parallel I am getting the following error:

Caused by: org.jruby.exceptions.NameError: (NameError) uninitialized constant Gem::Package
at org.jruby.RubyModule.const_missing(org/jruby/RubyModule.java:4336)
at RUBY.name_version_platform(gems_helper.rb:30)

I have tried to debug the jruby library and I have noticed that the constant map in Jruby in some thread is partially full and does not contain the constant for Gem::Package

In addition I am adding couple of links to problems that seem related to it:

#6139
https://bugs.ruby-lang.org/issues/921

[headius]

I don't believe that either of those issues are relevant, since they both involve autoload and you are explicitly loading both rubygems and rubygems/package.

Command-line use seems to work ok:

$ jruby -rrubygems -rrubygems/package -e 'p Gem::Package'
Gem::Package

However the error message you provide seems odd. Normally when there's a double colon lookup for a constant, only the last element is reported:

$ jruby -e 'p Foo::Package' 
NameError: uninitialized constant Foo
  const_missing at org/jruby/RubyModule.java:4338
         <main> at -e:1

In your case, the error is reported with the full double-colon name Gem::Package which makes it appear like that is the whole name of the constant that was accessed. I suspect something else unusual is happening, like some Java code looking up this constant using the colon name when it should do two lookups for Gem and Package separately (for example).

I'm not sure I can reproduce exactly your example with the code provided. Could you perhaps create a small repo that I can use to reproduce the problem on JRuby 9.4?

[headius]

My mistake... when the last element of the "colon2" constant form is the one that is missing, the rest of the nesting is also shown:

$ jruby -e 'p Gem::Foo'
NameError: uninitialized constant Gem::Foo
  const_missing at org/jruby/RubyModule.java:4336
         <main> at -e:1

I picked a poor example to test this in my previous comment.

Please do try to provide an example reproduction for me.

[Shahafgo]

Sure I will create an example and I will provide it to you, thanks

[Shahafgo]

Hi @headius here is a small repository I created for reporuction, all you need is there, just clone it, build and run the code from the main function, thanks (:

https://github.com/Shahafgo/jruby-test