Fix for NPE when `paymentMethodProps.getProperties()` returns null.

[beccagaspard]

Fix for NPE when paymentMethodProps.getProperties() returns null.

When payment control plugins are in use and an __EXTERNAL_PAYMENT__ payment method is added via AccountApi::createPaymentMethod, a NPE is thrown. Added check to skip merge when payment method properties are null.

Full stacktrace:

java.lang.NullPointerException: null
	at org.killbill.billing.util.PluginProperties.toMap(PluginProperties.java:41)
	at org.killbill.billing.util.PluginProperties.merge(PluginProperties.java:34)
	at org.killbill.billing.payment.core.PaymentMethodProcessor.addPaymentMethodWithControl(PaymentMethodProcessor.java:181)
	at org.killbill.billing.payment.api.DefaultPaymentApi.addPaymentMethodWithPaymentControl(DefaultPaymentApi.java:995)
	at org.killbill.billing.util.glue.KillbillApiAopModule$ProfilingMethodInterceptor$1.execute(KillbillApiAopModule.java:76)
	at org.killbill.commons.profiling.Profiling.executeWithProfiling(Profiling.java:33)
	at org.killbill.billing.util.glue.KillbillApiAopModule$ProfilingMethodInterceptor.invoke(KillbillApiAopModule.java:92)
	at org.killbill.billing.util.security.AopAllianceMethodInvocationAdapter.proceed(AopAllianceMethodInvocationAdapter.java:45)
	at org.apache.shiro.authz.aop.AuthorizingAnnotationMethodInterceptor.invoke(AuthorizingAnnotationMethodInterceptor.java:68)
	at org.killbill.billing.util.security.AopAllianceMethodInterceptorAdapter.invoke(AopAllianceMethodInterceptorAdapter.java:32)
	at org.killbill.billing.jaxrs.resources.AccountResource.createPaymentMethod(AccountResource.java:832)
	at org.killbill.commons.skeleton.metrics.TimedResourceInterceptor.invoke(TimedResourceInterceptor.java:69)
	at org.killbill.billing.server.modules.JaxRSAopModule$JaxRsMethodInterceptor$1.execute(JaxRSAopModule.java:87)
	at org.killbill.billing.util.entity.dao.DBRouterUntyped.withRODBIAllowed(DBRouterUntyped.java:57)
	at org.killbill.billing.server.modules.JaxRSAopModule$JaxRsMethodInterceptor.invoke(JaxRSAopModule.java:82)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
	at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$ResponseOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:205)
	at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
	at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
	at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
	at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
	at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
	at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
	at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1542)
	at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1473)
	at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1419)
	at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1409)
	at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:409)
	at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:558)
	at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:733)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
	at com.google.inject.servlet.ServletDefinition.doServiceImpl(ServletDefinition.java:286)
	at com.google.inject.servlet.ServletDefinition.doService(ServletDefinition.java:276)
	at com.google.inject.servlet.ServletDefinition.service(ServletDefinition.java:181)
	at com.google.inject.servlet.ManagedServletPipeline.service(ManagedServletPipeline.java:91)
	at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:85)
	at org.killbill.billing.server.security.TenantFilter.doFilter(TenantFilter.java:111)
	at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:82)
	at org.killbill.billing.server.filters.ResponseCorsFilter.doFilter(ResponseCorsFilter.java:75)
	at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:82)
	at ch.qos.logback.classic.helpers.MDCInsertingServletFilter.doFilter(MDCInsertingServletFilter.java:49)
	at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:82)
	at com.google.inject.servlet.ManagedFilterPipeline.dispatch(ManagedFilterPipeline.java:120)
	at com.google.inject.servlet.GuiceFilter.doFilter(GuiceFilter.java:135)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.shiro.guice.web.SimpleFilterChain.doFilter(SimpleFilterChain.java:44)
	at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
	at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
	at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
	at org.apache.shiro.guice.web.SimpleFilterChain.doFilter(SimpleFilterChain.java:41)
	at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
	at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
	at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
	at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
	at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
	at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
	at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at com.codahale.metrics.servlet.AbstractInstrumentedFilter.doFilter(AbstractInstrumentedFilter.java:111)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:221)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
	at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:683)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:436)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1078)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
	at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2517)
	at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2506)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:748)

[sbrossie]

I am fine with the PR as it is, but i am wondering if the fix should not be at the PluginProperties#merge level to handle the null case.

Also, in our JAXRS layer, probably retuning null in the first place is not so great - an ImmutableList.of() should be better i think.

👍

[beccagaspard]

Hey @sbrossie - made the changes as you suggested. Should I revert the original change in PaymentMethodProcessor as it should no longer be necessary?

[sbrossie]

Hey @sbrossie - made the changes as you suggested. Should I revert the original change in PaymentMethodProcessor as it should no longer be necessary?

I think it's fine to keep. Happy to merge it . @pierre Any objections?

[pierre]

Thanks!

[pierre]

Thanks!