ActiveAdminDatetimepicker::Base mattr_accessor :format defaults to nil

[gbirchmeier]

(version 0.2.0, rails 4.0.14, ruby 2.1.0, activeadmin 1.0.0.pre1)

If I don't explicitly set ActiveAdminDatetimepicker::Base.format = "%Y-%m-%d %H:%M" in an initializer, I get this exception when I submit my form or load the edit-object form:

no implicit conversion of nil into String

top of framework trace:
  active_admin_datetimepicker (0.2.0) lib/active_admin_datetimepicker/base.rb:31:in `strftime'
  active_admin_datetimepicker (0.2.0) lib/active_admin_datetimepicker/base.rb:31:in `input_value'
  active_admin_datetimepicker (0.2.0) lib/active_admin_datetimepicker/base.rb:24:in `input_html_options'

I traced this to lib/active_admin_datetimepicker/base.rb line 31. The variable format is nil.

It appears that the mattr_accessor :format block (same file) is supposed to set a default value for format, but my experience today is that it's not doing anything.

UPDATE:

(from #19) mattr_accessor :default_datetime_picker_options has the same defect.

[Fivell]

@gbirchmeier , looks like you're right about default value, can you create PR with fix ?

[gbirchmeier]

I will attempt it.

[gbirchmeier]

This is really frustrating, but I can't seem to reproduce this in a spec. See the specs I wrote in PR #23.

I figured out that on a live AA website, the exception is being thrown on a DateTimePickerInput object, which somehow gets created with both mattr_attributes as nil. However, when I create one of these objects in a spec, those values have non-nil values.

I don't know the innards of AA well enough to understand how it could create this object without giving those attrs a value.

@Fivell, do you have any idea? I'm not sure how to approach this.

[Fivell]

@gbirchmeier , it is not obvious for me as well for now, it will be very helpful if you can share some dummy application to let me reproduce it .

[gbirchmeier]

I have created a dummy rails app that replicates the bug.

Here you go: https://github.com/gbirchmeier/pickerbug

[Fivell]

@gbirchmeier , I figured out that default block for mattr_accessor can be used only from rails 4.1.0
you can see it by this commit rails/rails@7dfbd91

So there is 2 options, mention it in readme or setup default attributes manually. I think second option is ok, what do you think?

[Fivell]

fixed by #26

[gbirchmeier]

Ah, thanks. That makes sense.

I've updated my demo project to 0.3.0 and it looks good now. Problem solved.