NoMethodError: undefined method '[]' for nil with ruby3.4.0dev

[mtasaka]

Using ruby 3.4.0dev (2024-12-04 master e539342f65) +PRISM [x86_64-linux]
ruby/ruby@e539342

pupplet-lint git head 167ab94
rspec testsuite does not do anything but exits abnormally:

$ rspec spec/unit ; echo $?
rspec/json_expectations is not available
WARNING: `around(:context)` hooks are not supported and behave like `around(:example)`. Called from /builddir/build/GIT/puppet-lint/spec/unit/puppet-lint/bin_spec.rb:608:in 'block (3 levels) in <top (required)>'.

PuppetLint::Bin
  when running normally
    exitstatus

Finished in 0.00475 seconds (files took 0.32275 seconds to load)
1 example, 0 failures

1

Then explicitly executing testsuite shows backtrace error:

$ env RUBYLIB=$(pwd)/lib ./bin/puppet-lint ./spec/fixtures/test/manifests/init.pp
Whoops! It looks like puppet-lint has encountered an error that it doesn't
know how to handle. Please open an issue at https://github.com/puppetlabs/puppet-lint
and paste the following output into the issue description.
---
puppet-lint version: 4.2.4
ruby version: 3.4.0-p-1
platform: x86_64-linux
file path: ./spec/fixtures/test/manifests/init.pp
file contents:
---
# foo
class test {
}

---
error:
---
NoMethodError: undefined method '[]' for nil
/builddir/build/GIT/puppet-lint/lib/puppet-lint/data.rb:63:in 'PuppetLint::Data.tokens'
/builddir/build/GIT/puppet-lint/lib/puppet-lint/data.rb:608:in 'PuppetLint::Data.parse_control_comments'
/builddir/build/GIT/puppet-lint/lib/puppet-lint/checks.rb:26:in 'PuppetLint::Checks#load_data'
/builddir/build/GIT/puppet-lint/lib/puppet-lint/checks.rb:55:in 'PuppetLint::Checks#run'
/builddir/build/GIT/puppet-lint/lib/puppet-lint.rb:226:in 'PuppetLint#run'
/builddir/build/GIT/puppet-lint/lib/puppet-lint/bin.rb:85:in 'block in PuppetLint::Bin#run'
/builddir/build/GIT/puppet-lint/lib/puppet-lint/bin.rb:80:in 'Array#each'
/builddir/build/GIT/puppet-lint/lib/puppet-lint/bin.rb:80:in 'PuppetLint::Bin#run'
./bin/puppet-lint:7:in '<main>'
---

Works normally with ruby 3.3.6 (2024-11-05 revision 75015d4c1f) [x86_64-linux]

[mtasaka]

So this is due to ruby3.4 backtrace change:

https://github.com/ruby/ruby/blob/e539342f65e468fc7f926277eff61cb8b8a60622/NEWS.md?plain=1#L224-L242

Especially, now single quote is used instead of backtick .
So now this regex does not match:

puppet-lint/lib/puppet-lint/data.rb

Lines 60 to 63 in 167ab94

	begin
	caller(0..0).first[%r{`.*'}][1..-2]
	rescue NoMethodError
	caller(1..1).first[%r{`.*'}][1..-2]

Extra change is that backtrace now shows class name.

A fix for this is something like:

$ git diff
diff --git a/lib/puppet-lint/data.rb b/lib/puppet-lint/data.rb
index f219cf5..0518d58 100644
--- a/lib/puppet-lint/data.rb
+++ b/lib/puppet-lint/data.rb
@@ -58,12 +58,13 @@ class PuppetLint::Data
                          end
                        else
                          begin
-                           caller(0..0).first[%r{`.*'}][1..-2]
+                           caller(0..0).first[%r{[`'].*'}][1..-2]
                          rescue NoMethodError
-                           caller(1..1).first[%r{`.*'}][1..-2]
+                           caller(1..1).first[%r{[`'].*'}][1..-2]
                          end
                        end
 
+      calling_method.gsub!(/^.*[#\.]/, "")
       if calling_method == 'check'
         @tokens.dup
       else

[ekohl]

https://stackoverflow.com/questions/5100299/how-to-get-the-name-of-the-calling-method suggests a better method is to use caller_locations which returns Location objects which have a label method, avoiding the need to do any regular expression parsing.

The same thread mentions it's a Ruby 2 thing, but this Ruby 1 compatibility should have been dropped long ago. Also mentions that caller_locations is faster, so we can drop the RuboCop disable statements as well.