🐛 Raise parse errors on legacy extract path

CHANGELOG.md

@@ -29,6 +29,7 @@ Please file a bug if you notice a violation of semantic versioning.
 ### Fixed
 
 - `OAuth2::AccessToken` no longer raises `NoMethodError` when `expires_latency` is set but the token has no known expiry (no `expires_in`/`expires_at`, or `expires_in: 0`), e.g. `client.get_token(params, expires_latency: 30)` against a provider that omits `expires_in` by @iamibi
+- `OAuth2::Client#get_token` raises response parse errors (e.g. `JSON::ParserError`) when using the deprecated `extract_access_token` option, rather than returning `nil` by @dpep
 
 ### Security
 

lib/oauth2/client.rb

@@ -600,12 +600,15 @@ def build_access_token(response, access_token_opts, access_token_class)
     #
     # @api private
     def build_access_token_legacy(response, access_token_opts, extract_access_token)
-      extract_access_token.call(self, response.parsed.merge(access_token_opts))
-    rescue
-      # An error will be raised by the called if nil is returned and options[:raise_errors] is truthy, so this rescue is but temporary.
-      # Unfortunately, it does hide the real error, but this is deprecated legacy code,
-      #   and this was effectively the long-standing pre-existing behavior, so there is little point in changing it.
-      nil
+      parsed = response.parsed
+      begin
+        extract_access_token.call(self, parsed.merge(access_token_opts))
+      rescue
+        # An error will be raised by the called if nil is returned and options[:raise_errors] is truthy, so this rescue is but temporary.
+        # Unfortunately, it does hide the real error, but this is deprecated legacy code,
+        #   and this was effectively the long-standing pre-existing behavior, so there is little point in changing it.
+        nil
+      end
     end
 
     def oauth_debug_logging(builder)

spec/oauth2/client_spec.rb

@@ -1212,8 +1212,8 @@
           let(:status_code) { 200 }
           let(:extract_proc) { proc { |client, hash| raise ArgumentError } }
 
-          it "returns a nil :access_token" do
-            expect(client.get_token({}, {}, extract_proc)).to be_nil
+          it "raises the parse error" do
+            expect { client.get_token({}, {}, extract_proc) }.to raise_error(JSON::ParserError)
           end
         end
       end
@@ -1229,6 +1229,14 @@
             expect(token.response).to be_a OAuth2::Response
             expect(token.response.parsed).to eq("access_token" => "the-token")
           end
+
+          context "when extract_access_token raises an exception" do
+            let(:extract_proc) { proc { |client, hash| raise ArgumentError } }
+
+            it "returns a nil :access_token" do
+              expect(client.get_token({}, {}, extract_proc)).to be_nil
+            end
+          end
         end
 
         context "when Content-Type is not JSON" do