Allow configuration of trailing blank lines

[daviddavis]

No description provided.

[jonas054]

You should add the Max parameter in config/default.yml. Then you can remove || 0 because all configurations are based on the default so cop_config['Max'] is guaranteed to have a non-nil value.

[bbatsov]

Not sure such an option makes sense. Why would anyone want to have some trailing blank lines in their source code?

[daviddavis]

In our project, a lot of our files end with 1 trailing blank line:

class Whatever
# ...
end

I figured we would allow 1 trailing blank line. I'm leaning toward just cleaning up our files though so I will close this out.

[bbatsov]

By common convention (not only for Ruby) source files should end with just a newline. It doesn't make sense for me to start breaking such strongly established practice.

[jdickey]

There's a big difference between "newline at end of file" and "blank line at end of file" (two consecutive newlines). Some editors (e.g. Komodo) automatically add a blank line if one does not exist, as many people do find it easier to read that way. No team that I've been on in the last three decades used a standard requiring no blank lines at the end of files. Granted, Ruby has only been involved in the last ~5 years of that, but springing this new behaviour on people and having every single file report a violation is a bit much. I see the value in warning of multiple blank lines at the ends of files. I see no value whatever in a change that requires that an otherwise-useful new feature (the cop under discussion here) be disabled to avoid requiring touching every single source file in a project.

I know cops aren't doctors, but "first, do no harm" really should apply here, too.

[aaronmcadam]

Why was this not merged? How can I turn off this cop?

[jonas054]

The author closed it so it would have to be reopened first in order to be merged. I'm not sold on the idea of a Max parameter, but a parameter acting like a boolean switch, e.g. EnforcedStyle with values no_line (default) and one_line would be an improvement IMO, especially in light of what @jdickey said.

@bbatsov If you agree I can implement that and make a new pull request.

@aaronmcadam To disable the cop, just add

TrailingBlankLines:
  Enabled: false

in your .rubocop.yml file.

[aaronmcadam]

@jonas054 Yeah thanks I figured that bit out! What I'd like to figure out now is how to stop the autocorrect directive from removing the trailing new line when it runs.

[jonas054]

If you've disabled the cop, there will be no auto-correct action related to that offence.

[aaronmcadam]

@jonas054 ah, my bad, just tried it again and it's ok, must have been something else! Thanks for helping :)

[daviddavis]

@jonas054 I'd be happy to work on an EnforcedStyle config unless you want to.

[jonas054]

@daviddavis It's yours then! 😄

[bbatsov]

@daviddavis @jonas054 As I originally said - I'm against such a change, but I can live with it. Let's have an enforced style param with supported values final_newline and final_blank_line.

[daviddavis]

@bbatsov @jonas054 cool! thanks!

[jarinudom]

@bbatsov I would like to see this too, as there are a few reasons to have a trailing newline in your code. For example:

• cat will put your prompt on the same line as the last line of output unless you have a trailing newline (not to mention that if you actually wanted to concatenate two files it would jam the lines together)
• echo 'some_file' >> .gitignore won't work unless your .gitignore ends with a newline
• grep expects a newline at the end of the file
• Probably most importantly to me, diff and git changelogs will consider the (formerly last) line to have been changed when you add additional lines to the file, because you're adding a newline at that time. This is why both git and GitHub complain when you don't have newlines at the end of your files.

Couple of discussions here:
http://stackoverflow.com/questions/729692/why-should-files-end-with-a-newline
http://stackoverflow.com/questions/16072822/why-does-ruby-on-rails-generate-add-a-blank-line-to-the-end-of-a-file/16072987#16072987

I hope this doesn't come across as bikeshedding, I just wanted to point out that there are a bunch of practical reasons for it.

[fabiopelosin]

👍 for the EnforcedStyle

[jonas054]

I'm reopening and assigning myself.

[daviddavis]

@jonas054 thanks. I apologize for not getting around to it.

[jonas054]

@daviddavis No problem!

[fabiopelosin]

Nice! 🍻

[jarinudom]

Yay thank you :)