raise inextricable response body error

for when the body isn't extractable because it's not one of
known/expected body types. at the moment the raise results in a mere
runtime error, which isn't informative.

lib/vigiles.rb

@@ -34,7 +34,13 @@ def self.spec=(spec)
     @spec = spec
   end
 
-  sig { params(req: ActionDispatch::Request, res: Rack::Response).returns(T.nilable(Archive::Conversation)) }
+  sig do
+    params(
+      req: ActionDispatch::Request,
+      res: Rack::Response
+    )
+      .returns(T.nilable(Archive::Conversation))
+  end
   def self.maybe_record_conversation(req:, res:)
     return unless should_record?(req)
 
@@ -47,7 +53,7 @@ def self.maybe_record_conversation(req:, res:)
   def self.configure(&blk)
     blk.call(spec)
 
-    # TODO(yaw, 2024-06-15): ensure that the spec is valid.
+    # TODO(yaw, 2024-07-15): ensure that the spec is valid.
     # ensure that for every content type a recorder is configured. otherwise
     # assign the general recorder for unknown content types.
   end

lib/vigiles/archive/response.rb

@@ -10,6 +10,17 @@ class Response < T::Struct
       const :payload,      Types::Payload
       const :status,       Integer
 
+      class InextricableResponseBodyError < StandardError
+        sig { returns(String) }
+        attr_reader :response_body_class
+
+        sig { params(response_body_class: String).void }
+        def initialize(response_body_class:)
+          @response_body_class = response_body_class
+          super("failed to extract response body: response_body_class=#{response_body_class}")
+        end
+      end
+
       class ResponseBodyTooDeepError < StandardError
         sig { returns(Integer) }
         attr_reader :max_stack_depth
@@ -33,7 +44,7 @@ def initialize(stack_depth, max_stack_depth)
         case (inner_body = body.instance_variable_get(:@body))
         when Rack::BodyProxy then extract_body_from_rack_body_proxy(inner_body, stack_depth + 1)
         when Array           then inner_body[0] || "null"
-        else raise
+        else                 raise InextricableResponseBodyError.new(inner_body.class.name)
         end
       end
 

lib/vigiles/utilities/json.rb

@@ -13,6 +13,7 @@ def self.parse_benignly(text)
         ::JSON.parse(text)
       rescue StandardError
         return text unless block_given?
+
         yield text
       end
     end