Raising an error when query methods have blank arguments.

[wangjohn]

Currently, whenever an activerecord query is included with a nil or nil-like object, no argument error is given. For instance:

Posts.limit().all = Posts.all

That relation is completely useless when there are blank-like arguments. For methods which this doesn't make sense for, I'm adding checks which will raise an ArgumentError.

[tadast]

I would disagree. Often times you want this 'null pattern' behaviour when generating parameters dynamically and this change would force you to write unnecessary conditional statements.

[jeremy]

@tadast Could you show some code that's affected, before & after? Note that we're checking that any arguments are passed, not the argument isn't null or an empty string.

>> [''].blank?
=> false

[tadast]

Right, I got confused by splat operator again 😊 Sorry for the FUD @wangjohn, @jeremy

[rafaelfranca]

Seems good. Could you add a changelog entry?

[jeremy]

@tadast 👍

[wangjohn]

Changelog entry has been added.

[tadast]

Sorry, I don't want to cause any more trouble, but I'm thinking about it again... What if someone has a method like this:

def fancy_filter(options = {})
  related = []
  query = {}
  if options[:author_name]
    query[:author] = { name: options[:author_name] }
    related << :author
  end
  where(query).references(related)
end

would it not break things? In cases like this people would have to make sure to omit the #references call unless options[:author_name] is present.

[wangjohn]

So where is handled separately. I only changed the functionality where blank arguments make strictly no sense. Where still returns self.

[rafaelfranca]

@wangjohn the @tadast's problem still occurs with references

[jeremy]

Again:

>> [[]].blank?
=> false

It'll only break if you do .references(*related), which would splat an empty array.

[tadast]

🙊

[richardkmichael]

I'm confused too; sorry!

Given the discussion above, the CHANGELOG.md description is misleading, I think. It reads: "are the arguments blank", not "are there arguments". I'm confused by the examples:

Post.limit()     # => raises error  
Post.include([]) # => raises error

The limit method has not been changed to call check_empty_arguments, so how will .limit() raise?
As mentioned in the discussion above, with .include([]), args.blank? == false, so how will it raise?

Are there tests for this I can read?

[wangjohn]

Sorry, the CHANGELOG is misleading and there is an error in it. I'm sending in a PR to fix this and add some more documentation and tests #9332.