Allow null input objects in arguments during field usage analysis

[lyricsboy]

Problem

When passing in an explicit null value for a nullable input object-type argument on a field, field usage analysis will raise an exception like this:

NoMethodError: undefined method `arguments' for nil:NilClass
    graphql-ruby/lib/graphql/analysis/ast/field_usage.rb:43:in `block in extract_deprecated_arguments'
    graphql-ruby/lib/graphql/analysis/ast/field_usage.rb:37:in `each_pair'
    graphql-ruby/lib/graphql/analysis/ast/field_usage.rb:37:in `extract_deprecated_arguments'
    graphql-ruby/lib/graphql/analysis/ast/field_usage.rb:22:in `on_leave_field'

Solution

Skip arguments with null values during field usage analysis.

[rmosolgo]

Thanks for this fix! It looks good to me.

It looks like adding a new field to the dummy schema broke some assertions about the introspection result on that schema, do you mind updating those tests to include the newly-added field?

[lyricsboy]

Thanks! All tests are passing locally for me now.