`TypeError` after upgrading to 4.33

[travisbell]

After upgrading to 4.33, we're getting this error when calling Braintree::ClientTokenGateway.new().generate:

TypeError: no implicit conversion of Symbol into Integer (TypeError)

        result[:client_token][:value]
                              ^^^^^^
from /usr/local/bundle/gems/braintree-4.33.0/lib/braintree/client_token_gateway.rb:22:in 'String#[]'

It looks like perhaps the result is coming back as a string now, instead of a symbol which is probably related to using Nokogiri.

[nalshapub]

Acknowledge. I'll take this back to the team.

[jeppeliisberg]

Error Response Parsing Also Affected by Same Root Cause

We've encountered the same root cause affecting a different part of the gem: error response parsing.

Our Environment

• Braintree: 4.33.0
• Ruby: 3.3.9
• Rails: 8.0.3 (also fails on 7.2.2.2)

Symptoms

When Braintree API returns validation error responses (422), the XML parser collapses nested structures, causing:

TypeError: no implicit conversion of Symbol into Integer
  lib/braintree/error_result.rb:15:in `initialize'

Specifically, ErrorResult initialization fails because response[:api_error_response] returns a String instead of the expected Hash.

Evidence of Structure Collapse

Testing the XML parser directly:

xml = "<api-error-response><message>Test</message><errors><errors type=\"array\"></errors></errors></api-error-response>"

# Expected (pre-4.33):
{:api_error_response=>{:message=>"Test", :errors=>{:errors=>[]}}}

# Actual (4.33 with Nokogiri):
{:api_error_response=>"Test"}  # Collapsed!

The parser in lib/braintree/xml/parser.rb line 78 collapses single-element Arrays:

when "Array"
  value.map! { |i| _transform_xml(i) }
  case value.length
    when 0 then nil
    when 1 then value.first  # Collapses to first element
    else value
  end

Under the Nokogiri implementation (new in 4.33), this over-flattens nested structures.

Impact

Any Braintree operation that results in validation errors is broken.

Root Cause Confirmation

This appears to be the same Nokogiri XML parsing issue you're seeing with ClientTokenGateway.generate(), just manifesting in error response handling instead of token generation.

The v4.33 changelog notes "Switch from libxml-ruby to Nokogiri to allow use with JRuby", but the XML transformation logic wasn't updated to handle Nokogiri's different parsing behavior.

[nalshapub]

Hi, we just released a fix. Please test and let us know if there are any issues.

[travisbell]

4.33.1 is looking good. Haven't seen an error yet. 👍🏼

[goofansu]

Encountered the error on 4.33.0, and confirmed 4.33.1 fixes the error.

[Fjan]

Yes, 4.33.1 fixes the problem

[nalshapub]

Thank y'all for confirming.