Rescue not capturing failure - ruby-on-rails

Question

I'm missing something here, but for some reason my begin then rescue Ruby code isn't capturing this error:
#<ActiveResource::ResourceInvalid: Failed. Response code = 422. Response message = Unprocessable Entity.>
This is my code:
begin
ShopifyAPI::CarrierService.create(with some arguments)
rescue StandardError => e
pp e
end
It doesn't ever capture it. In my rescue section I've tried the above but also:
rescue Exception => e
rescue ActiveResource::Errors => e
All with no luck. Where did I go astray?
Thanks
EDIT:
This is the full error, it not really anymore info, but here goes:
#<ShopifyAPI::CarrierService:0x0000000357a0a0
#attributes=
{"name"=>"XXXX",
"callback_url"=>
"https://XX-XX-XX-XX.c9users.io/receive_rate_request",
"format"=>"json",
"service_discovery"=>"true",
"carrier_service_type"=>"api"},
#errors=
#<ActiveResource::Errors:0x00000003578930
#base=#<ShopifyAPI::CarrierService:0x0000000357a0a0 ...>,
#messages={:base=>["you already have XXX set up for this shop"]}>,
#persisted=false,
#prefix_options={},
#remote_errors=
#<ActiveResource::ResourceInvalid: Failed. Response code = 422. Response message = Unprocessable Entity.>,
#validation_context=nil>
That's it!

Answer 1

Because it is not raising an exception, If you want to raise the exception when the response is false, you may have to use create with bang
begin
ShopifyAPI::CarrierService.create!(with some arguments)
rescue StandardError => e
pp e
end

Answer 2

According to the ActiveResource code (lib/active_resource/base.rb):
# <tt>404</tt> is just one of the HTTP error response codes that Active Resource will handle with its own exception. The
# following HTTP response codes will also result in these exceptions:
#
# * 200..399 - Valid response. No exceptions, other than these redirects:
# * 301, 302, 303, 307 - ActiveResource::Redirection
# * 400 - ActiveResource::BadRequest
# * 401 - ActiveResource::UnauthorizedAccess
# * 403 - ActiveResource::ForbiddenAccess
# * 404 - ActiveResource::ResourceNotFound
...
# * 422 - ActiveResource::ResourceInvalid (rescued by save as validation errors)
So it indicates that 422's are rescued by save on validation, which happens when .create is fired, and are bubbled up as validation errors instead.
Looking at lib/active_resource/validations.rb, you can see the ResourceInvalid exception is gobbled:
# Validate a resource and save (POST) it to the remote web service.
# If any local validations fail - the save (POST) will not be attempted.
def save_with_validation(options={})
perform_validation = options[:validate] != false
# clear the remote validations so they don't interfere with the local
# ones. Otherwise we get an endless loop and can never change the
# fields so as to make the resource valid.
#remote_errors = nil
if perform_validation && valid? || !perform_validation
save_without_validation
true
else
false
end
rescue ResourceInvalid => error
# cache the remote errors because every call to <tt>valid?</tt> clears
# all errors. We must keep a copy to add these back after local
# validations.
#remote_errors = error
load_remote_errors(#remote_errors, true)
false
end
So I wonder if it's logging that an exception happened, but is not actually raising an exception because it turns it in to a return false. It does say "local validations" in the comment, but sets remote_errors, so it's not perfectly clear where this code path is executed.