Fix for log tailer when the log file doesn't exist.

[j-manu]

If the log file doesn't exist, log tailer errors out and takes down the server with it. Currently this does not happen because even if the log directory doesn't exist, https://github.com/rails/rails/blob/master/railties/lib/rails/application/bootstrap.rb#L27 creates it and the log file will be created.

[josevalim]

We should initialize the variables regardless, probably setting it to nil.

[j-manu]

Ok. Will issue a new PR with the changes

[j-manu]

A question: Is :: needed here (for File) or is it just best practice to use it ? On line 7 there is no :: for
File.expand_path(Rails.root). If needed, I will change the commit

[j-manu]

@tenderlove is this OK now?

[spastorino]

Y U NO USE an else there to assign cursor and file to nil?

[j-manu]

Brevity :)

[skull-squadron]

Who needs readability?

@file, @cursor = ::File.exists?(path) ? [::File.open(path, 'r'), ::File.size(path)] : nil

[swrobel]

This needs to be merged into 3-2-stable

> rm log/development.log
> rails s
=> Booting WEBrick
=> Rails 3.2.3 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
/gems/railties-3.2.3/lib/rails/rack/log_tailer.rb:8:in `size': No such file or directory - log/development.log (Errno::ENOENT)

[swrobel]

@tenderlove please merge into 3-2-stable