执行时
grails list-plugin-updates --stacktrace
我收到以下错误：
| Environment set to development....
| Error Error executing script ListPluginUpdates: java.lang.NullPointerException: Cannot get property 'plugin' on null object (NOTE: Stack trace has been filtered. Use --verbose to see entire trace.)
java.lang.NullPointerException: Cannot get property 'plugin' on null object
at ListPluginUpdates$_run_closure1_closure5_closure6.doCall(ListPluginUpdates.groovy:28)
at ListPluginUpdates$_run_closure1_closure5_closure6.doCall(ListPluginUpdates.groovy)
at ListPluginUpdates$_run_closure1_closure5.doCall(ListPluginUpdates.groovy:27)
at ListPluginUpdates$_run_closure2_closure9.doCall(ListPluginUpdates.groovy:67)
at ListPluginUpdates$_run_closure2.doCall(ListPluginUpdates.groovy:66)
at ListPluginUpdates$_run_closure1.doCall(ListPluginUpdates.groovy:26)
at ListPluginUpdates$_run_closure1.doCall(ListPluginUpdates.groovy)
at ListPluginUpdates$_run_closure4.doCall(ListPluginUpdates.groovy:85)
at org.codehaus.gant.GantMetaClass.invokeMethod(GantMetaClass.java:133)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16_closure18.doCall(GantBinding.groovy:185)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16_closure18.doCall(GantBinding.groovy)
at org.codehaus.gant.GantBinding.withTargetEvent(GantBinding.groovy:90)
at org.codehaus.gant.GantBinding.this$4$withTargetEvent(GantBinding.groovy)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16.doCall(GantBinding.groovy:185)
at org.codehaus.gant.GantBinding$_initializeGantBinding_closure5_closure16.doCall(GantBinding.groovy)
at gant.Gant$_dispatch_closure5.doCall(Gant.groovy:381)
at gant.Gant$_dispatch_closure7.doCall(Gant.groovy:415)
at gant.Gant$_dispatch_closure7.doCall(Gant.groovy)
at gant.Gant.withBuildListeners(Gant.groovy:427)
at gant.Gant.this$2$withBuildListeners(Gant.groovy)
at gant.Gant$this$2$withBuildListeners$0.callCurrent(Unknown Source)
at gant.Gant.dispatch(Gant.groovy:415)
at gant.Gant.this$2$dispatch(Gant.groovy)
at gant.Gant.invokeMethod(Gant.groovy)
at gant.Gant.executeTargets(Gant.groovy:591)
at gant.Gant.executeTargets(Gant.groovy:590)
| Error Error executing script ListPluginUpdates: java.lang.NullPointerException: Cannot get property 'plugin' on null object
谁能告诉我我做错了什么？