Integer-index encode all arrays

[brandur]

Changes all arrays from classic Rack encoding:

arr[]=...&arr[]=...&arr[]=...

To integer-indexed encoding:

arr[0]=...&arr[1]=...&arr[2]=...

We think that this should be tractable now that we've fully converted
all endpoints over to the new AbstractAPIMethod infrastructure on the
backend (although we should do a little more testing to make sure that
all endpoints still work).

As part of the conversion, we also remove any places that we were "spot
encoding" to get required integer-indexed syntax. This should now all be
built in.

cc @stevene-stripe @zanker-stripe

[brandur-stripe]

This method was designed to check that arrays being encoded were compatible with Rack syntax for arrays of maps — now that we're using integer-indexed arrays everywhere, we don't need to check this anymore.

[zanker-stripe]

Seems sane to me, beyond 👍ing that we should re-verify the changes are working fine against the server.

[zanker-stripe]

Do we have a test that verifies an array of hashes too? {foo: [{bar: :a}, {bar: :b}]} -> foo[0][bar]=a&foo[1][bar]=b?

[brandur-stripe]

Yeah! Check just a bit lower in "#url_encode should prepare strings for HTTP", and it seems to do a pretty good job.

[zanker-stripe]

LGTM

[brandur-stripe]

Okay, I tested a few places where we've used non-integer-index arrays:

1. The expand parameter.
2. attributes when creating a new product.
3. types when listing events.

Numbers 1 and 2 worked fine, but number 3 didn't. Script:

require "stripe"
Stripe.api_key = "sk_test_BQokikJOvBiI2HlWgH4olfQ2"

events = Stripe::Event.list(
  limit: 10,
  type: ["invoice.created", "invoice.updated"],
)

events.each do |event|
  p event.type
end

And result:

$ STRIPE_LOG=debug bundle exec ruby event_list.rb
INFO Request to Stripe API method=get num_retries=0 path=/v1/events
DEBU Request details query_params="limit=10&type[0]=invoice.created&type[1]=invoice.updated"
INFO Response from Stripe API api_version=2018-07-27 elapsed=0.222724 method=get path=/v1/events request_id=req_syHFJh71e34U0y status=400
DEBU Response details body="{  \"error\": {    \"message\": \"Invalid string: [\\"invoice.created\\", \\"invoice.updated\\"]\",    \"param\": \"type\",    \"type\": \"invalid_request_error\"  }}" request_id=req_syHFJh71e34U0y
DEBU Dashboard link for request request_id=req_syHFJh71e34U0y url="https://dashboard.stripe.com/test/logs/req_syHFJh71e34U0y"
ERRO Stripe API error status=400 error_message="Invalid string: [\"invoice.created\", \"invoice.updated\"]" error_param=type error_type=invalid_request_error request_id=req_syHFJh71e34U0y
/Users/brandur/stripe/stripe-ruby/lib/stripe/stripe_client.rb:296:in `handle_error_response': Invalid string: ["invoice.created", "invoice.updated"] (Stripe::InvalidRequestError)
        from /Users/brandur/stripe/stripe-ruby/lib/stripe/stripe_client.rb:247:in `rescue in execute_request_with_rescues'
        from /Users/brandur/stripe/stripe-ruby/lib/stripe/stripe_client.rb:215:in `execute_request_with_rescues'
        from /Users/brandur/stripe/stripe-ruby/lib/stripe/stripe_client.rb:171:in `execute_request'
        from /Users/brandur/stripe/stripe-ruby/lib/stripe/api_operations/request.rb:19:in `request'
        from /Users/brandur/stripe/stripe-ruby/lib/stripe/api_operations/list.rb:9:in `list'
        from event_list.rb:4:in `<main>'

It looks like we encoded the parameter as expected, but the server balked at it — so we may still have a little more backend work to do before we can fully enable this.

[brandur-stripe]

And nevermind — I used type instead of types (apparently they're both supported, but only types will take an array).

types works fine.

Okay, I'm pretty comfortable with this change (and therefore the one in Java as well) then.

@remi-stripe Anything else that you can think of?

[remi-stripe]

This looks good to me, especially as you explicitly tested multiple edge-cases!

[brandur-stripe]

Thanks Remi! Let's go for it then.

[brandur-stripe]

Released as 3.22.0.