"requiring version.rb" strategy has some issues.
- cannot work when cross-compiling
- often introduces wrong namespace
- must know the superclasses
- costs at each runtime than at build-time
etc.
https://github.com/ruby/actions/runs/500526558?check_suite_focus=true#step:16:127
```
Failures:
1) Bundler.setup when Bundler is bundled doesn't blow up
Failure/Error: expect(err).to be_empty
expected `"fatal: not a git repository (or any of the parent directories): .git\nfatal: not a git repository (o...the parent directories): .git\nfatal: not a git repository (or any of the parent directories): .git".empty?` to return true, got false
Commands:
$ /home/runner/work/actions/actions/snapshot-master/ruby \
-I/home/runner/work/actions/actions/snapshot-master/lib:/home/runner/work/actions/actions/snapshot-master/spec/bundler \
-rsupport/hax -rsupport/artifice/fail \
/home/runner/work/actions/actions/snapshot-master/libexec/bundle install --retry 0
Resolving dependencies...
Using bundler 2.1.4
Bundle complete! 1 Gemfile dependency, 1 gem now installed.
Use `bundle info [gemname]` to see where a bundled gem is installed.
fatal: not a git repository (or any of the parent directories): .git
fatal: not a git repository (or any of the parent directories): .git
fatal: not a git repository (or any of the parent directories): .git
# $? => 0
$ /home/runner/work/actions/actions/snapshot-master/ruby \
-I/home/runner/work/actions/actions/snapshot-master/lib:/home/runner/work/actions/actions/snapshot-master/spec/bundler \
-rsupport/hax -rsupport/artifice/fail \
/home/runner/work/actions/actions/snapshot-master/libexec/bundle exec ruby -e \
require\ \'bundler\'\;\ Bundler.setup
fatal: not a git repository (or any of the parent directories): .git
fatal: not a git repository (or any of the parent directories): .git
fatal: not a git repository (or any of the parent directories): .git
# $? => 0
# ./spec/bundler/runtime/setup_spec.rb:1056:in `block (3 levels) in <top (required)>'
# ./spec/bundler/spec_helper.rb:111:in `block (3 levels) in <top (required)>'
# ./spec/bundler/spec_helper.rb:111:in `block (2 levels) in <top (required)>'
# ./spec/bundler/spec_helper.rb:78:in `block (2 levels) in <top (required)>'
make: *** [yes-test-bundler] Error 1
```
