change error name & no cache on error

lib/json/jwk/set/fetcher.rb

@@ -2,7 +2,7 @@ module JSON
   class JWK
     class Set
       module Fetcher
-        class MalformedJWKSet < JWT::Exception; end
+        class UnexpectedFormat < JWT::Exception; end
 
         class Cache
           def fetch(cache_key, options = {})
@@ -73,7 +73,10 @@ def self.fetch(jwks_uri, kid:, auto_detect: true, **options)
             end
           )
 
-          raise MalformedJWKSet, "Malformed JWK Set: #{parsed_jwks.inspect}" unless parsed_jwks.is_a?(Hash) && parsed_jwks['keys'].is_a?(Array)
+          unless parsed_jwks.is_a?(Hash) && parsed_jwks['keys'].is_a?(Array)
+            cache.delete(cache_key, options)
+            raise UnexpectedFormat
+          end
 
           jwks = Set.new(parsed_jwks)
           cache.delete(cache_key, options) if jwks[kid].blank?

spec/json/jwk/set/fetcher_spec.rb

@@ -69,7 +69,7 @@ def fetch(cache_key, options = {})
         end
       end
 
-      def delete(cache_key)
+      def delete(cache_key, options = nil)
         # ignore
       end
     end
@@ -112,13 +112,13 @@ def delete(cache_key)
         end
 
         context "when the JWKS uri returns a structure that's not a valid JWK Set" do
-          it "raises a JSON::JWK::Set::Fetcher::MalformedJWKSet error" do
+          it "raises a JSON::JWK::Set::Fetcher::UnexpectedFormat error" do
             stub_request(:get, jwks_uri).to_return(
               status: 200,
               body: '"hello there"' # Note that this is valid JSON, but not a valid JWK Set
             )
 
-            expect { subject }.to raise_error(JSON::JWK::Set::Fetcher::MalformedJWKSet)
+            expect { subject }.to raise_error(JSON::JWK::Set::Fetcher::UnexpectedFormat)
           end
         end