Various fixes for Rails 6

[sebjacobs]

Whilst investigating a Rails 6 upgrade (6.0.0.beta3) I discovered the following issues:

• The ActionView::Template#formats method has been deprecated [1]
• The Template handler API has changed [2] (already fixed on 4-0-dev)

This branch attempts to fix these issues whilst retaining support for Rails <= 5.2.

[1] https://www.github.com/rails/rails/commit/ca5e23ed4d8
[2] https://www.github.com/rails/rails/commit/28f88e0074

[JonRowe]

Hi, thanks for this, Rails 6 support work is on going in 4-0-dev so you need to target that, your second commit isn't necessary as that fix has already been done, although I don't think we've seen the formats issue before.

[JonRowe]

I suggest you rebase if you can!

[sebjacobs]

Argh ok sorry about that I hadn't spotted that branch. I have rebased as requested.

Thanks for taking a look!

[JonRowe]

Great, is this a Rails specific or object specific? e.g. will we encounter both methods in one version of Rails? If so we prefer conditionally defining a method to extract this to save runtime conditionals.

[sebjacobs]

template.formats is deprecated in Rails 6, so we could rely on the Rails version instead, perhaps something like this?:

def self.template_format(template)
  if Rails::VERSION::STRING >= '6'
    template.format
  else
    template.formats
  end
end

[JonRowe]

Right so if this is Rails 6 only we'd typically do:

if Rails::VERSION::STRING >= '6'
  def self.template_format(format)
    template.format
  end
else
  def self.template_format(format)
    template.formats
  end
end

[sebjacobs]

That makes sense, thanks @JonRowe!

[sebjacobs]

I have fixed up the suggested changes in (
81fdc8a)

[JonRowe]

Thanks!

[benoittgt]

Thanks a lot @sebjacobs