`TypeError` on `require 'digest/sha2'`

[ojab]

$ ruby -v
truffleruby 21.3.0, like ruby 2.7.4, GraalVM CE Native [x86_64-linux]
$ bundle exec irb
irb(main):001:0> require 'digest/sha2'

From: /home/ojab/.rbenv/versions/truffleruby+graalvm-21.3.0/graalvm/languages/ruby/lib/truffle/truffle/cext.rb @ line 979 :

    974:       const = Object.const_get(path, false)
    975:     rescue NameError
    976:       raise ArgumentError, "undefined class/module #{path}"
    977:     end
    978:     unless const.is_a?(Class)
 => 979:       binding.irb
    980:       raise TypeError
    981:     end
    982:     const
    983:   end
    984: 

irb(Truffle::CExt):001:0> path
=> "Digest"
irb(Truffle::CExt):002:0> const.is_a?(Class)
=> false
irb(Truffle::CExt):003:0> const.is_a?(Module)
=> true
irb(Truffle::CExt):004:0> 
Traceback (most recent call last):
/home/ojab/.rbenv/versions/truffleruby+graalvm-21.3.0/graalvm/languages/ruby/lib/truffle/truffle/cext.rb:980:in `rb_path_to_class': TypeError (TypeError)

[eregon]

I cannot reproduce, could you share your Gemfile or parts of it?

$ ruby -v
truffleruby 21.3.0, like ruby 2.7.4, GraalVM CE Native [x86_64-linux]
$ irb
irb(main):001:0> require 'digest/sha2'
=> true

[eregon]

The full backtrace you get without the binding.irb would also be helpful.

[ojab]

hmm, right, it happens only inside bundle. Let me debug it some more and I will get back with reproducer.

[ojab]

ah, quite easy, Gemfile.lock has digest-3.0.0, so

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'digest', '3.0.0'
end

require 'digest/sha2'

[ojab]

I guess could be #1390 duplicate?

[eregon]

Sorry, I missed your reply somehow.

That repro works correctly now (no output and no error), because TruffleRuby master already ships with digest 3.0.0 as a default gem.

gem i digest fails though:

$ gem i digest
Fetching digest-3.0.0.gem
Building native extensions. This could take a while...
ERROR:  Error installing digest:
	ERROR: Failed to build gem native extension.

    current directory: /home/eregon/.rubies/truffleruby-dev/lib/gems/gems/digest-3.0.0/ext/digest
/home/eregon/.rubies/truffleruby-dev/bin/truffleruby -I /home/eregon/.rubies/truffleruby-dev/lib/mri -r ./siteconf20211112-17074-qqi4qj.rb extconf.rb
creating Makefile

current directory: /home/eregon/.rubies/truffleruby-dev/lib/gems/gems/digest-3.0.0/ext/digest
make DESTDIR\= clean

current directory: /home/eregon/.rubies/truffleruby-dev/lib/gems/gems/digest-3.0.0/ext/digest
make DESTDIR\=
compiling digest.c
linking shared-object digest.so

current directory: /home/eregon/.rubies/truffleruby-dev/lib/gems/gems/digest-3.0.0/ext/digest
make DESTDIR\= install
/usr/bin/install -c -m 0755 digest.so ./.gem.20211112-17074-pymstw
/usr/bin/install: missing destination file operand after './digest.h'
Try '/usr/bin/install --help' for more information.
make: *** [Makefile:177: /digest.h] Error 1
make: *** Waiting for unfinished jobs....
installing digest libraries

make install failed, exit code 2

Gem files will remain installed in /home/eregon/.rubies/truffleruby-dev/lib/gems/gems/digest-3.0.0 for inspection.
Results logged to /home/eregon/.rubies/truffleruby-dev/lib/gems/extensions/x86_64-linux/3.0.2.4/digest-3.0.0/gem_make.out

In general it's probably better to avoid an explicit dependency on the digest gem, but I guess maybe it's through a transitive dependency or so?

We'll likely need fixes in https://github.com/ruby/digest to make this work (either always use the builtin version, or make sure the C extension works and add truffleruby in CI there).

[eregon]

After setting sitehdrdir in RbConfig and fixing the check for rb_path2class() it works fine:

$ gem i digest
...
$ ruby -v -rdigest/sha2 -e 'p Digest::SHA2.hexdigest "abc"'
truffleruby 22.0.0-dev-ffc70bd5, like ruby 3.0.2, Interpreted JVM [x86_64-linux]
"ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad"

[ojab]

Yep, it's transitive via updated net-smtp that we need for ruby/net-smtp#26.

So I guess it's a minor incompatibility issue with particular cext at the end of the day?
Bailing out in truffleruby-dev looks fine, but building ext and bailing out on require in 21.3 looks like a truffleruby bug for me.

If it would work — even better, anyway.

[eregon]

looks like a truffleruby bug for me.

Yeah, that's a fair assessment, it was a bug of rb_path2class() to only accept classes and not modules.

Regarding the issue label/changelog, compatibility is typically used for "didn't work yet" and bug for incorrect behavior which can cause incorrect result.

[eregon]

To clarify, it'll be fixed soon and it will be in the next release.