[rb] Fix add_cause method not being able to process an array of hashes

rb/lib/selenium/webdriver/remote/response.rb

@@ -58,12 +58,30 @@ def assert_ok
 
         def add_cause(ex, error, backtrace)
           cause = Error::WebDriverError.new
+          backtrace = backtrace_from_remote(backtrace) if backtrace.is_a?(Array)
           cause.set_backtrace(backtrace)
           raise ex, cause: cause
         rescue Error.for_error(error)
           ex
         end
 
+        def backtrace_from_remote(server_trace)
+          server_trace.filter_map do |frame|
+            next unless frame.is_a?(Hash)
+
+            file = frame['fileName']
+            line = frame['lineNumber']
+            method = frame['methodName']
+
+            class_name = frame['className']
+            file = "#{class_name}(#{file})" if class_name
+
+            method = 'unknown' if method.nil? || method.empty?
+
+            "[remote server] #{file}:#{line}:in `#{method}'"
+          end
+        end
+
         def process_error
           return unless self['value'].is_a?(Hash)
 

rb/sig/lib/selenium/webdriver/remote/response.rbs

@@ -22,6 +22,8 @@ module Selenium
 
         def add_cause: (Error::WebDriverError ex, String error, Array[String] backtrace) -> Error::WebDriverError
 
+        def backtrace_from_remote: -> Array[String]
+
         def process_error: () -> Array[Hash[untyped, untyped]]
       end
     end

rb/spec/integration/selenium/webdriver/error_spec.rb

@@ -47,6 +47,13 @@ module WebDriver
       rescue WebDriver::Error::NoSuchElementError => e
         expect(e.backtrace).not_to be_empty
       end
+
+      it 'has backtrace when using a remote server' do
+        options = Selenium::WebDriver::Options.chrome(binary: '/path/to/nonexistent/chrome')
+        Selenium::WebDriver.for :remote, url: 'http://localhost:4444/wd/hub', options: options
+      rescue WebDriver::Error::SessionNotCreatedError => e
+        expect(e.cause).to be_a(WebDriver::Error::WebDriverError)
+      end
     end
   end # WebDriver
 end # Selenium