Check if HOME can change or not instead of ENV["CI"]

[znz]

Tests of snapshot tarball are failed, because the CIs run without write permissions to HOME.
So I want to check the desired feature instead of ENV["CI"].

https://github.com/ruby/actions/runs/7617816773?check_suite_focus=true#step:17:2135

  Failure: test_frame_filtering_works_with_unexpanded_path_and_expanded_skip_path(DEBUGGER__::BasicBacktraceTest):
    Test::Unit::AssertionFailedError: 
    --------------------
    | Debugger Session |
    --------------------
    
    > [1, 2] in /tmp/debug-20220801-16442-89w16l.rb
    > =>   1| load "~/foo.rb"
    >      2| Foo.new.bar
    > =>#0	<main> at /tmp/debug-20220801-16442-89w16l.rb:1
    > file = File.open('/home/runner/foo.rb', 'w+') { |f| f.write('class Foo; def bar; debugger; end; end') }
    > �[?2004h(rdbg) file = File.open('/home/runner/foo.rb', 'w+') { |f| f.write('class Foo; def bar; debugger; end; end') }
    > �[?2004l
  eval error: Permission denied @ rb_sysopen - /home/runner/foo.rb
    >   (rdbg)//tmp/debug-20220801-16442-89w16l.rb:1:in `initialize'
    >   (rdbg)//tmp/debug-20220801-16442-89w16l.rb:1:in `open'
    >   (rdbg)//tmp/debug-20220801-16442-89w16l.rb:1:in `<main>'
    > nil
    > c
    > �[?2004h(rdbg) c
    > �[?2004l
  /tmp/debug-20220801-16442-89w16l.rb:1:in `load': cannot load such file -- ~/foo.rb (LoadError)
    > 	from /tmp/debug-20220801-16442-89w16l.rb:1:in `<main>'

[st0012]

@znz Sorry that @ko1 reminded me this may be happening but I forgot to follow up.

But I'm confused by GH Action's behavior because its document says ENV["CI"] should always be true, which applies to this repo. And we can also see it set in the build's Run env | sort step. However it's not picked up by the tests 🤔

[znz]

This fails because chmod -w $HOME at https://github.com/ruby/actions/blob/9d0cf8fffecac5f9c8b8600e452021b87458d974/.github/workflows/snapshot-master.yml#L143 to check that tests does not affect normal environments.
So I want to write nothing under $HOME on CI too.

[st0012]

Thanks for explanation 🙏

However, this change also allows modifying $HOME when it's run locally, which was the patch originally trying to prevent.

❯ cat ~/.rdbgrc
foo

❯ be ruby test/console/rdbg_option_test.rb -n /rc_file/
Calling `DidYouMean::SPELL_CHECKERS.merge!(error_name => spell_checker)' has been deprecated. Please call `DidYouMean.correct_error(error_name, spell_checker)' instead.
Calling `DidYouMean::SPELL_CHECKERS.merge!(error_name => spell_checker)' has been deprecated. Please call `DidYouMean.correct_error(error_name, spell_checker)' instead.
Loaded suite test/console/rdbg_option_test
Started
..
Finished in 0.49796 seconds.
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
2 tests, 12 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
4.02 tests/s, 24.10 assertions/s

❯ cat ~/.rdbgrc
cat: /Users/st0012/.rdbgrc: No such file or directory

I think we can summarize our needs as:

• If it's a local environment, we don't want to modify $HOME
• If it's a CI environment, it's fine to write files in $HOME
  • However, in ruby/actions's CI we also don't want $HOME to be writable

So maybe the conditions should be this instead?

USE_TMP_HOME = !ENV["CI"] || HOME_CANNOT_CHANGE

# startup
@pty_home_dir =
  if USE_TMP_HOME
    Dir.mktmpdir
  else
    Dir.home
  end

# shutdown
if USE_TMP_HOME
  FileUtils.remove_entry @pty_home_dir
end

[znz]

Thank you for your summarize.
I update the conditions.

[st0012]

I can confirm it's not affecting local ~/.rdbgrc anymore. Sorry again for the trouble and thanks for the fix 😄