logname may not produce a login name

Comienza con spec/ruby/library/etc/getlogin_spec.rb:22 y reproduce el ejemplo fallido de Etc.getlogin en JRuby en el entorno de GitHub Actions. Compara los comandos disponibles para obtener el nombre de inicio de sesión y el valor de entorno descrito en el issue, y luego haz que la spec gestione los entornos sin una terminal de control. La tarea estará terminada cuando la spec pase en JRuby y conserve un fallback cuando los comandos no estén disponibles.

Running the specs on JRuby on Github Actions, we see the following message and failing spec:

...
logname: no login name
...
1)
Etc.getlogin returns the name associated with the current login activity FAILED
Expected "runner" == ""
to be truthy but was false
/home/runner/work/jruby/jruby/spec/ruby/library/etc/getlogin_spec.rb:22:in `block in <main>'
...

This can occur when logname is run without a controlling terminal. I'm unsure whether this GHA env is not setting up a tty, or if there's an issue launching the command in JRuby that prevents it inheriting the parent terminal, but it seems like id would be a more reliable command to use:

diff --git a/spec/ruby/library/etc/getlogin_spec.rb b/spec/ruby/library/etc/getlogin_spec.rb
index 7a4fd79ae2..f0dde84ccb 100644
--- a/spec/ruby/library/etc/getlogin_spec.rb
+++ b/spec/ruby/library/etc/getlogin_spec.rb
@@ -18,11 +18,13 @@ describe "Etc.getlogin" do
         else
           # Etc.getlogin returns the same result of logname(2)
           # if it returns non NULL
-          if system("which logname", out: File::NULL, err: File::NULL)
+          if system("which id", out: File::NULL, err: File::NULL)
+            Etc.getlogin.should == `id -un`.chomp
+          elsif system("which logname", out: File::NULL, err: File::NULL)
+            # fallback to `logname` command since `id` is not available
             Etc.getlogin.should == `logname`.chomp
           else
-            # fallback to `id` command since `logname` is not available
-            Etc.getlogin.should == `id -un`.chomp
+            Etc.getlogin.should == ENV['LOGNAME']
           end
         end
       else

However I think we are also stacking too many conditions here. I'm unsure of the "best" way to get the current login, but clearly logname has issues that make it undesirable.

FWIW some forums suggest logname -t which will ensure a tty is created, but this flag is not present on BSD-likes.