mimic_JSON compatibility with Faraday

[werleo]

Recent changes in FaradayMiddleware https://github.com/lostisland/faraday_middleware/pull/156/files

makes oj incompatible with it.

We use rails, faraday and oj.
Everything worked fine until change mentioned above.
Right now we receive ParsingError with a message: "options must be a hash".

This is the same message which you will receive calling JSON.parse with incorrect options.

Example:

JSON.parse( { ok: true }.to_json, '')
ArgumentError: options must be a hash.
        from (irb):17:in `parse'

I'm not sure if it is Oj error or faraday_middleware error.

For now, we need to remove oj completely or use faraday_middleware in the previous version.

[ohler55]

Since the JSON gem also raises an exception it seems Oj is working as expected in mimicking the JSON gem. The same behavior is also present in a Rails console. The documentation for bot the JSON gem and Rails calls for the second argument, if present, to be an options hash. The faraday_middleware seems to have introduced a bug.

Looking at the patch code it is clear they have introduced a bug as the @parse_options will end of defaulting to nil instead of {}.

[stefansedich]

@ohler55 it looks to me as it does not behave the same as the JSON gem, for example:

irb(main):002:0> JSON.parse('{}', nil)
=> {}

Then if I add Oj and attempt the same thing it blows up:

irb(main):005:0> Oj.mimic_JSON
irb(main):006:0> JSON.parse('{}', nil)
ArgumentError: options must be a hash.

I have patched the faraday_middleware to fix the issue for now but just wanted to chime in on this here as it does look like Oj handles nil options differently.

[ohler55]

I stand corrected. For nil the behavior is different than an empty string, or any string for that matter.

irb(main):001:0> JSON.parse('{}', '')
ArgumentError: wrong number of arguments (given 2, expected 1)
	from /Users/ohler/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/json-2.1.0/lib/json/common.rb:156:in `initialize'
	from /Users/ohler/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/json-2.1.0/lib/json/common.rb:156:in `new'
	from /Users/ohler/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/json-2.1.0/lib/json/common.rb:156:in `parse'
	from (irb):1
	from /Users/ohler/.rbenv/versions/2.4.1/bin/irb:11:in `<main>'

I'll update Oj to special case nil. I thank you for making the change in faraday_middleware.

[werleo]

I'm sorry for the confusion about the empty string.
I forgot that in project console I have already mimic_JSON turned on.

Thank you @stefansedich @ohler55 for making changes in your gems to fix the problem.

[iMacTia]

Thank you for your understanding, I'll create a link to our PR to keep this tracked:
lostisland/faraday_middleware#156

[ohler55]

Just released Oj 3.3.3 that allows a nil second argument to parse but continues to raise an exception on anything else other than a Hash.

[werleo]

I just update gem version and all tests are passing.

Thank you very much.
We may close this issue.