Excess spaces while rendering multiline string

[atomAltera]

Hello, today I end up with strange issue in Rails 5:

Here is how a simple text.html.erb file looks like:
<textarea><%= "a\nb\nc" %></textarea>
And here is what it produce:

I'm talking about these leading spaces before second and third strings.

In my code I have a form with textarea:

.form
  =form_for article do |f|
    .form-group
      =field_label f, :text, true
      =f.text_area :text, class: %w(form-control), rows: 20, placeholder: t('placeholder.article_text')

And the same issue happens there on Edit action

I found out that the reason is haml-rails gem in Gemfile. Without it <textarea><%= "a\nb\nc" %></textarea> forks fine, but with it, it adds extra spaces.

[remomueller]

I've run into the same issue when trying out the Rails 5 beta3. I've made a project that is a simple Rails 5 app that demonstrates the issue with haml 4.0.7 here:

https://github.com/remomueller/TextAreaSpacing

Note that the project does not have haml-rails in it. Hope that helps debugging, as I'd love to keep using Haml in Rails 5!

Here are some notes to launch the project:

To Recreate

Clone code:

git clone https://github.com/remomueller/TextAreaSpacing.git
cd TextAreaSpacing
bundle install

Launch Server

rails s

Open http://localhost:3000/items/new

Create item with

Name:
Name

Description:
My Description
Will have spaces in front of this line

Click "Create item"

Click 'Edit'

Extra spacing will be in front of 'Will have spacecs'

[remomueller]

Just an FYI, this extra spacing can be fixed by doing the following on the form:

= f.text_area :description, value: item.description.to_s.gsub("\r\n", "\r")

Edit
Thanks to @droptheplot, looks like this can be fixed by doing the following as well in config/initializers/haml.rb

# config/initializers/haml.rb
require 'haml/template'

Haml::Template.options[:ugly] = true

[olivierlacan]

@norman @amatsuda Any idea why this regression is occurring with Rails 5? Could be a coincidence with Ruby 2.3 maybe?

[olivierlacan]

Just to isolate the issue I tried to run Rails 5 with Ruby 2.2 instead of 2.3 and the issue still occurs so something must have changed in Rails 5 to cause this.

[k0kubun]

This may be resolved by Haml 5 because it doesn't have ugly: false mode. Please try Haml 5.0.0.beta.2 and reopen this if the problem still exists on Haml 5.

[olivierlacan]

@k0kubun I've tested 5.0.0.beta.2 and as far as I can tell it fixes the issue.

I've submitted two pull request for haml-rails and html2haml to make them allow 5.0.0:

• Allow Haml 5.0.0 haml-rails#128
• Relax Haml dependency to allow for newer versions html2haml#80

[k0kubun]

Ah, good catch. Thanks!