input `bundler: 2.7.2` didn't run `bundle lock` with the correct version

[dentarg]

Ensure the following before filing this issue

• I verified it reproduces with the latest version with - uses: ruby/setup-ruby@v1 (see Versioning policy)

• I tried to reproduce the issue locally by following the workflow steps (including all commands done by ruby/setup-ruby, except for Downloading Ruby & Extracting Ruby),
  and it did not reproduce locally (if it does reproduce locally, it's not a ruby/setup-ruby issue)

Are you running on a GitHub-hosted runner or a self-hosted runner?

GitHub-hosted runner

Link to the failed workflow job (must be a public workflow job, so the necessary information is available)

https://github.com/sinatra/sinatra/actions/runs/20523194500/job/58961833171?pr=2136#step:4:4

Any other notes?

• Here the bundler: input is set to 2.72.: https://github.com/sinatra/sinatra/actions/runs/20523194500/job/58961833171?pr=2136#step:4:4
• Here bundler 2.7.2 is installed: https://github.com/sinatra/sinatra/actions/runs/20523194500/job/58961833171?pr=2136#step:4:32
• but BUNDLED WITH in the generated lockfile is 4.0.3 https://github.com/sinatra/sinatra/actions/runs/20523194500/job/58961833171?pr=2136#step:4:487

[dentarg]

Looks like BUNDLER_VERSION (the env variable) is only set for Bundler 1

setup-ruby/bundler.js

Lines 165 to 170 in ae195bb

	if (bundlerVersion.startsWith('1') && common.isBundler2PlusDefault(engine, rubyVersion)) {
	// If Bundler 1 is specified on Rubies which ship with Bundler 2+,
	// we need to specify which Bundler version to use explicitly until the lockfile exists.
	console.log(`Setting BUNDLER_VERSION=${bundlerVersion} for "bundle config|lock" commands below to ensure Bundler 1 is used`)
	envOptions = { env: { ...process.env, BUNDLER_VERSION: bundlerVersion } }
	}

I think it would make sense to include BUNDLER_VERSION in envOptions that the bundle lock command uses. I haven't looked if it makes sense in all scenarios but at least when bundler: is set to a specific version.

setup-ruby/bundler.js

Line 184 in ae195bb

await exec.exec('bundle', ['lock'], envOptions)

[dentarg]

For the record I'm able to workaround this issue like this (removing the generated lockfile, running bundle install with BUNDLER_VERSION set) sinatra/sinatra@c694c06

[eregon]

I see, thanks for the report.
I think this is only a problem when there is no checked-in Gemfile.lock, as that would pick the right version due to Bundler auto-switching.

[eregon]

Repro'd in https://github.com/ruby/setup-ruby/actions/runs/20625380512/job/59234986980