Detect wrong plugin naming which contains extra kind prefix

[kenhys]

Which issue(s) this PR fixes:

Fixes N/A

Bit related issue: https://github.com/fluent-plugins-nursery/fluent-package-builder/issues/334

What this PR does / why we need it:

As a plugin naming scheme, register_xxx should not be pre-fixed with kind.

For examples, input plugin in_xxx.rb, @type xxx is specified in section. output plugin out_xxx.rb, @type xxx is specified in section.

There is a well known failure case, plugin doesn't detected because of not following above plugin naming rule.

In this PR, it checks whether prefixed plugin name is specified, then it raise an error with more informative message.

Docs Changes:

N/A

Release Note:

N/A

[kenhys]

I'll simplify test case.

[kenhys]

TODO: check plugin gemdir.

[kenhys]

What is the good way to detect dummy plugin? Just idea: launch fluentd with --gem-path and put dummy plugin for it. But Gem::Specification.find_all can't detect it. :thinking:

[kenhys]

Even though launched via assert_fluentd_fails_to_start with --gemfile, it cause an error with " error: You seem to use bundle exec already." It seems that BUNDLE_BIN_PATH checked and exit there.

[github-actions[bot]]

This PR has been automatically marked as stale because it has been open 90 days with no activity. Remove stale label or comment or this PR will be closed in 30 days

[ashie]

I close this pull request that has been pending for a long time and has no solution for now, and not so serious even if it's not resolved.