Do we need to require the .ru extension for rackup files?

[dentarg]

Not ending your rackup file with .ru leads to strange errors due to this code

puma/lib/puma/rack/builder.rb

Lines 155 to 169 in c2aa737

	def self.parse_file(config, opts = Options.new)
	options = {}
	if config =~ /\.ru$/
	cfgfile = ::File.read(config)
	if cfgfile[/^#\\(.*)/] && opts
	options = opts.parse! $1.split(/\s+/)
	end
	cfgfile.sub!(/^__END__\n.*\Z/m, '')
	app = new_from_string cfgfile, config
	else
	require config
	app = Object.const_get(::File.basename(config, '.rb').capitalize)
	end
	[app, options]
	end

Examples:

$ echo "run [200, {} ['OK']]" > foo.rb

$ puma ./foo.rb
Puma starting in single mode...
* Puma version: 6.4.2 (ruby 3.2.2-p53) ("The Eagle of Durango")
*  Min threads: 0
*  Max threads: 5
*  Environment: development
*          PID: 34772
! Unable to load application: NoMethodError: undefined method `run' for main:Object
/Users/dentarg/Dropbox/mort/code-snippets/rack-3/foo.rb:1:in `<top (required)>': undefined method `run' for main:Object (NoMethodError)

run [200, {} ['OK']]
^^^
	from <internal:/Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/3.2.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
	from <internal:/Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/3.2.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/rack-3.0.9/lib/rack/builder.rb:66:in `parse_file'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/configuration.rb:368:in `load_rackup'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/configuration.rb:290:in `app'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/runner.rb:162:in `load_and_bind'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/single.rb:44:in `run'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/launcher.rb:194:in `run'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/cli.rb:75:in `run'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/bin/puma:10:in `<top (required)>'
	from /Users/dentarg/.arm64_rubies/3.2.2/bin/puma:25:in `load'
	from /Users/dentarg/.arm64_rubies/3.2.2/bin/puma:25:in `<main>'

$ echo 'rackup "./foo.rb"' | puma --config /dev/stdin
Puma starting in single mode...
* Puma version: 6.4.2 (ruby 3.2.2-p53) ("The Eagle of Durango")
*  Min threads: 0
*  Max threads: 5
*  Environment: development
*          PID: 35386
! Unable to load application: NoMethodError: undefined method `run' for main:Object
/Users/dentarg/Dropbox/mort/code-snippets/rack-3/foo.rb:1:in `<top (required)>': undefined method `run' for main:Object (NoMethodError)

run [200, {} ['OK']]
^^^
	from <internal:/Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/3.2.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
	from <internal:/Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/3.2.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/rack-3.0.9/lib/rack/builder.rb:66:in `parse_file'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/configuration.rb:368:in `load_rackup'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/configuration.rb:290:in `app'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/runner.rb:162:in `load_and_bind'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/single.rb:44:in `run'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/launcher.rb:194:in `run'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/cli.rb:75:in `run'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/bin/puma:10:in `<top (required)>'
	from /Users/dentarg/.arm64_rubies/3.2.2/bin/puma:25:in `load'
	from /Users/dentarg/.arm64_rubies/3.2.2/bin/puma:25:in `<main>'

without ./ your file is not found

$ echo 'rackup "foo.rb"' | puma --config /dev/stdin
Puma starting in single mode...
* Puma version: 6.4.2 (ruby 3.2.2-p53) ("The Eagle of Durango")
*  Min threads: 0
*  Max threads: 5
*  Environment: development
*          PID: 35352
! Unable to load application: LoadError: cannot load such file -- foo.rb
<internal:/Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/3.2.0/rubygems/core_ext/kernel_require.rb>:85:in `require': cannot load such file -- foo.rb (LoadError)
	from <internal:/Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/3.2.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/rack-3.0.9/lib/rack/builder.rb:66:in `parse_file'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/configuration.rb:368:in `load_rackup'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/configuration.rb:290:in `app'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/runner.rb:162:in `load_and_bind'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/single.rb:44:in `run'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/launcher.rb:194:in `run'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/lib/puma/cli.rb:75:in `run'
	from /Users/dentarg/.arm64_rubies/3.2.2/lib/ruby/gems/3.2.0/gems/puma-6.4.2/bin/puma:10:in `<top (required)>'
	from /Users/dentarg/.arm64_rubies/3.2.2/bin/puma:25:in `load'
	from /Users/dentarg/.arm64_rubies/3.2.2/bin/puma:25:in `<main>'