Extension gems built for JRuby warn when switching Java version

[headius]

RubyGems warns if an extension gem in JRuby is built for one Java version and then the user switches to another Java version.

Ignoring io-console-0.5.6 because its extensions are not built. Try: gem pristine io-console --version 0.5.6

This affects all gems that have an extensions field in their gemspecs, because in all such cases RubyGems tracks whether the extension build has been run at all. It does not matter if the gem chooses not to actually build an extension, as is the case for some JRuby-specific versions of gems like io-console.

The problem is that RubyGems uses the value of RbConfig::CONFIG['arch'] to determine that platform. JRuby provides the Java version number in that field, which means that installing an extension on one Java version will warn if not re-installed for a different Java version.

[simi]

That check is actually useful. It saved me few times already.

I have seen gems with optional build deps. not trigering this error when installed properly. I was looking at io-console extconf (https://github.com/ruby/io-console/blob/41b6f095745758f979e72bd83518ad6e8cbe2419/ext/io/console/extconf.rb), but it seems a little cryptic for me to read.

Is there any simple minimal gem to reproduce this when installed?

[headius]

Well, io-console on JRuby is the one I can think of offhand, since I saw the warnings earlier today.

The key line there is this:

File.write("Makefile", dummy_makefile($srcdir).join(""))

Where is the code that decides to print this error? I'm curious why it sees my installed io-console as not "installed properly". It installed without error, but it does skip the extension build.

I will try to find another good example gem.

[headius]

bindex is another gem that I believe optionally builds its extension, and I have seen warnings about it as well.

[nobu]

I didn't see that warning.

$ rbenv local
jruby-9.2.11.1

$ rbenv exec gem install io-console
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.headius.backport9.modules.Modules to method sun.nio.ch.NativeThread.signal(long)
WARNING: Please consider reporting this to the maintainers of com.headius.backport9.modules.Modules
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Fetching io-console-0.5.6.gem
Building native extensions. This could take a while...
Successfully installed io-console-0.5.6
Parsing documentation for io-console-0.5.6
Installing ri documentation for io-console-0.5.6
Done installing documentation for io-console after 0 seconds
1 gem installed

$ rbenv exec ruby -e 'p Gem::Specification.find_by_name("io-console").missing_extensions?' 2>/dev/null
false

[deivid-rodriguez]

Would it be possible to get a repro for this ticket?

[deivid-rodriguez]

Closing due to lack of feedback. Feel free to reopen with a repro!

[headius]

@deivid-rodriguez Another example of this appears to be related to RVM, but I am not clear who is really at fault. The message comes from RG, but may be triggered by RVM's gemset logic?

jruby/warbler#374

[deivid-rodriguez]

I'm not clear either... :/

As long as I can get a repro, I can look into it!

[headius]

Hey I think this might be reproducible using a build from JRuby master (or possibly a JRuby 9.2.x build with latest RG) this way:

• gem install jruby-launcher, which builds a binary executable jruby for JRuby's bin dir
• try to run something that requires a non-existent file, which will trigger RubyGems gem-searching logic

I get the following output:

$ jruby -rjunk -e 1
Ignoring jruby-launcher-1.1.18-java because its extensions are not built. Try: gem pristine jruby-launcher --version 1.1.18
LoadError: no such file to load -- junk
  require at org/jruby/RubyKernel.java:1014
  require at /Users/headius/projects/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:85

I get this for other gems that claim an extension but do not build it. I assume there is some logic looking for a build extension... perhaps that is too aggressive?

[headius]

Poking this one again... I still do not have simple steps to reproduce, but I am not the only one who has seen this. It may be due to using Ruby switchers that have multiple gem paths, but I'm not sure.

This SO post is the same problem I have: https://stackoverflow.com/questions/38797458/ignoring-gem-because-its-extensions-are-not-built

Forcing everything to be pristine also fixes it for me but I do not understand how gems get into this state.