Non-blocking start

[dre-hh]

hi, how hard would it be to make robe not blocking the main emacs interface on starting. rails projects with a lot of gems tend to have really bad startup times?

[dgutov]

Why? You don't have to start it right away.

[dre-hh]

as long as it starting, one cannot do anything. i am not starting it right away.

[sandric]

Yes, I can approve that - robe-start hangs emacs for me for like 5 seconds, I assume its loading environment to pry console.

[dgutov]

Here's a question. Suppose we have a new command, robe-start-nonblocking.

Would you still expect it to start the REPL in the background, or would it rely on the REPL being already launched?

[vlymar]

I too am interested in this feature, but I recognize there are some tradeoffs.

Would you still expect it to start the REPL in the background, or would it rely on the REPL being already launched?

I'd prefer it to start the REPL in the background. The way I bump against this blocking behavior is usually (note: I use spacemacs):

1. I start a new emacs session
2. I attempt to jump to the definition of a ruby method
3. I get a prompt No ruby console running. Launch automatically? (y or n)
4. I hit y
5. A list of the possible rails environments comes up, and I select one
6. Emacs locks up while the console is loaded

I'd prefer for the editor to never be locked up, but I see that it might be jarring for a user to trigger a robe command, then get no indication that the command worked (while the console is loaded in the background), the suddenly have the effect of their command to happen several seconds later while they may have done several other things in the editor.

Perhaps theres some way to have a loading indicator somewhere in the UI?

As an alternative I may look into triggering info-ruby-console-auto automatically when I first start emacs.

[stardiviner]

Here is my personal settings for robe auto starting, hope this can help some people.

  ;; ruby-mode has keybinding [C-c C-s] for `inf-ruby'.
  ;; auto start robe `robe-start' after start `inf-ruby'.
  (defun my-robe-start ()
    (interactive)
    (unless robe-running
      (robe-start)))

  (defadvice inf-ruby-console-auto (after inf-ruby-console-auto activate)
    "Run `robe-start' after `inf-ruby-console-auto' started."
    (my-robe-start))

  (with-eval-after-load 'projectile-rails
    (define-key projectile-rails-mode-map
      [remap inf-ruby] 'inf-ruby-console-auto))

  (defadvice inf-ruby (after inf-ruby activate)
    "Run `robe-start' after `inf-ruby' started."
    (my-robe-start))

  (define-key enh-ruby-mode-map (kbd "C-c C-s") 'inf-ruby)

  ;; auto start robe process for completing
  (defun my-robe-auto-start ()
    (unless robe-running
      (call-interactively 'inf-ruby)))
  (add-hook 'enh-ruby-mode-hook #'my-robe-auto-start)

[dgutov]

@stardiviner Does that work in any way asynchronously?

I imagine you still have to wait for it to start when the first Ruby file in a given session is opened.

[stardiviner]

@dgutov Yes, just automate this start process for me for daily Ruby usage.
I agree your opinion of the robe REPL don't need to be async because user need a launched REPL to make sure can work. Not like big REPL like CIDER which will block Emacs for a long time if it is sync.

[dgutov]

@stardiviner Thanks for the clarification. Regarding your code:

• It might not work as intended anymore, because robe-running is now a buffer-local variable since the introduction of multi-project support. On the other hand, it'll probably continue to function okay for a while because inf-ruby-console-auto does not do much if the console is already running.

• If robe-start hanging Emacs for several seconds is the main issue, you might get away with only starting the REPL process automatically. inf-ruby and inf-ruby-console-auto both work asynchronously, so that should get you waiting less. M-x robe-start afterwards should work instantly.

[dgutov]

All that aside, I have implemented the asynchronous version. But it ended up being fairly convoluted.

Everybody interested, please check out the robe-start-async branch and see if it really makes your life better.

[dgutov]

To clarify @vlymar: robe-jump still uses the synchronous version, and will block until the server is started.

I can't imagine how it would work differently without causing weird behaviors if the user e.g. changes the window configuration.