Support default extension gems

[eregon]

This an issue to track all default gems with an extension, which might need specific support for TruffleRuby.
For some, we might just reuse the C extension and add TruffleRuby in the CI of those gems.

These default extension gems are problematic when they included in a Gemfile.lock, https://bugs.ruby-lang.org/issues/18567#note-30 has more details.
Related JRuby issue: jruby/jruby#6682

For some extensions gems, we have a different implementation, typically pure-Ruby.
For some extensions gems we use them as-is (just need to add truffleruby in CI).

• bigdecimal: Add TruffleRuby in CI ruby/bigdecimal#247
• cgi: should add to CI and look into failures. JRuby support PR for cgi/escape Add TruffleRuby support and add it in CI ruby/cgi#44
• date
• debug: actually a bundled gem Compile iseq_collector.c logic only on CRuby ruby/debug#1039
• digest: Add Digest framework support #1390 We probably want to use the C extension to support ruby/digest.h
• etc: Add TruffleRuby in CI and use the correct fallback pattern for rb_io_descriptor() ruby/etc#27
• fcntl
• fiddle
• io-console: Use the C extension on truffleruby ruby/io-console#23
• io-nonblock: Add TruffleRuby & JRuby in CI and use the correct fallback pattern for rb_io_descriptor() ruby/io-nonblock#12
• io-wait
• json: Test with TruffleRuby in CI flori/json#402
• openssl
• pathname
• pp: Fixes for Data and add TruffleRuby in CI ruby/pp#20
• psych
• racc
• readline-ext
• stringio: we have a pure-Ruby implementation, similar to strscan Do not compile the C extension on TruffleRuby ruby/stringio#71 Add workflow to ensure the gem installs fine on truffleruby ruby/stringio#74
• strscan: we have a pure-Ruby implementation require "strscan.so" uses the strscan gem and does not work #2420 Add support for TruffleRuby in the gem ruby/strscan#35
• syslog
• zlib Add truffleruby-head in CI ruby/zlib#62

Pure-Ruby gems (good to add truffleruby in CI):

• rdoc: Use a more portable way to check if code is parseable ruby/rdoc#1032
• timeout: Reimplement Timeout.timeout with a single thread and a Queue ruby/timeout#15 the original pure-Ruby impl is too slow with 1 new Thread per call

[chrisseaton]

Do JRuby have an approach to this problem? Do they all include Java code?

[eregon]

Yes basically JRuby's approach so far is to mostly upstream their JRuby-specific extension Java code into those default gems' repositories (and publish a java platform gem).
You can check the linked PRs in the linked JRuby issue for more details.

[eregon]

Here is a list of default gems with extensions in 3.1:

$ grep -a -R extensions lib/gems/specifications/default  | sort
lib/gems/specifications/default/bigdecimal-3.1.1.gemspec:  s.extensions = ["ext/bigdecimal/extconf.rb".freeze]
lib/gems/specifications/default/cgi-0.3.5.gemspec:  s.extensions = ["ext/cgi/escape/extconf.rb".freeze]
lib/gems/specifications/default/date-3.2.2.gemspec:  s.extensions = ["ext/date/extconf.rb".freeze]
lib/gems/specifications/default/digest-3.1.0.gemspec:  s.extensions = ["ext/digest/bubblebabble/extconf.rb".freeze, "ext/digest/extconf.rb".freeze, "ext/digest/md5/extconf.rb".freeze, "ext/digest/rmd160/extconf.rb".freeze, "ext/digest/sha1/extconf.rb".freeze, "ext/digest/sha2/extconf.rb".freeze]
lib/gems/specifications/default/etc-1.3.0.gemspec:  s.extensions = ["ext/etc/extconf.rb".freeze]
lib/gems/specifications/default/fcntl-1.0.1.gemspec:  s.extensions = ["ext/fcntl/extconf.rb".freeze]
lib/gems/specifications/default/fiddle-1.1.0.gemspec:  s.extensions = ["ext/fiddle/extconf.rb".freeze]
lib/gems/specifications/default/io-console-0.5.11.gemspec:  s.extensions = ["ext/io/console/extconf.rb".freeze]
lib/gems/specifications/default/io-nonblock-0.1.0.gemspec:  s.extensions = ["ext/io/nonblock/extconf.rb".freeze]
lib/gems/specifications/default/io-wait-0.2.1.gemspec:  s.extensions = ["ext/io/wait/extconf.rb".freeze]
lib/gems/specifications/default/json-2.6.1.gemspec:  s.extensions = ["ext/json/ext/generator/extconf.rb".freeze, "ext/json/ext/parser/extconf.rb".freeze, "ext/json/extconf.rb".freeze]
lib/gems/specifications/default/openssl-3.0.1.gemspec:  s.extensions = ["ext/openssl/extconf.rb".freeze]
lib/gems/specifications/default/pathname-0.2.0.gemspec:  s.extensions = ["ext/pathname/extconf.rb".freeze]
lib/gems/specifications/default/psych-4.0.4.gemspec:  s.extensions = ["ext/psych/extconf.rb".freeze]
lib/gems/specifications/default/racc-1.6.0.gemspec:  s.extensions = ["ext/racc/cparse/extconf.rb".freeze]
lib/gems/specifications/default/readline-ext-0.1.4.gemspec:  s.extensions = ["ext/readline/extconf.rb".freeze]
lib/gems/specifications/default/stringio-3.0.1.gemspec:  s.extensions = ["ext/stringio/extconf.rb".freeze]
lib/gems/specifications/default/strscan-3.0.1.gemspec:  s.extensions = ["ext/strscan/extconf.rb".freeze]
lib/gems/specifications/default/syslog-0.1.0.gemspec:  s.extensions = ["ext/syslog/extconf.rb".freeze]
lib/gems/specifications/default/zlib-2.1.1.gemspec:  s.extensions = ["ext/zlib/extconf.rb".freeze]

And for the raw list:

grep -a -R extensions lib/gems/specifications/default  | sort | ruby -e 'puts STDIN.readlines.map { |line| line[/\/([a-z-]+?)-\d/,1] }'

We should prioritize adding truffleruby in the CI of those to make sure they work and keep working on truffleruby.