util.async: Behaviour change: continue to process queued items after errors

spec/util_async_spec.lua

@@ -156,6 +156,30 @@ describe("util.async", function()
 				assert.equal(r.state, "ready");
 				assert.equal(last_processed_item, "hello again");
 			end);
+
+			it("should continue to process work items", function ()
+				local wait, done, last_item;
+				local runner_func = spy.new(function (item)
+					if item == "error" then
+						error("test error");
+					elseif item == "wait-error" then
+						wait, done = async.waiter();
+						wait();
+						error("test error");
+					end
+					last_item = item;
+				end);
+				local runner = async.runner(runner_func, { error = spy.new(function () end) });
+				runner:enqueue("one");
+				runner:enqueue("error");
+				runner:enqueue("two");
+				runner:run();
+				assert.equal(r.state, "ready");
+				assert.equal(r.state, r.notified_state);
+				assert.spy(runner_func).was.called(3);
+				assert.spy(runner.watchers.error).was.called(1);
+				assert.equal(last_item, "two");
+			end);
 		end);
 	end);
 	describe("#waiter", function()

util/async.lua

@@ -180,6 +180,9 @@ function runner_mt:run(input)
 		local handler = self.watchers[state];
 		if handler then handler(self, err); end
 	end
+	if n > 0 then
+		return self:run();
+	end
 	return true, state, n;
 end