Errors when creating composite value topics using webclient's search/create dialog

Here is an error description I can not make fully sense of (yet). It's reproducible and I tried to document the behaviour as well as possible. I also tried to circumvent the error for the last 2 hours but did not succeed.

I think it would be great for us to know, if I can workaround these errors by adapting the dmx-webpages further to DMX 5.0 or if these are errors which must be adressed at platform level. What follows are two distinct errors, involving slightly different type defintitions but might have a very similar cause of error.

Here is the rough, type def outline which I deemed relevant for the interpretation of these errors, but I can't make sense of these stacktraces.

1. Header (Value Type)
   -> Title
   -> Many Buttons (Entity Type)
   --> Title (identityAttr)
   --> Link (identityAttr)
   

2. Section (Value Type) -> Title
   -> ...
   -> Many Tiles (Value Type)
   

1. Header topic creation

When I try to create a new Header topic using the webclients search/create dialog.

A Header in webpages can contain "Buttons" and is defined in detail in th file Migration6, see the following link: https://github.com/mukil/dmx-webpages/blob/master/src/main/resources/migrations/migration6.json

When pressing "Create" I get the following error message.

INFORMATION: ##### Logging in as "admin" => SUCCESSFUL!
Jul 31, 2020 11:08:24 AM systems.dmx.topicmaps.TopicmapsPlugin getTopicmap
INFORMATION: Fetching topicmap 2590, includeChildren=false
Jul 31, 2020 11:08:46 AM systems.dmx.core.impl.DMXObjectModelImpl update
INFORMATION: Updating association 842 (typeUri="dmx.core.composition")
Jul 31, 2020 11:08:56 AM systems.dmx.core.impl.DMXObjectModelImpl update
INFORMATION: Updating association 1487 (typeUri="dmx.core.composition")
Jul 31, 2020 11:09:02 AM systems.dmx.core.util.UniversalExceptionMapper logException
SCHWERWIEGEND: Request "POST /core/topic" failed. Responding with 500 (Internal Server Error). The original exception/error is:
java.lang.RuntimeException: Creating topic failed, model=TopicModelImpl {
    "id": -1,
    "typeUri": "de.mikromedia.header",
    "children": {
        "de.mikromedia.header.js": {
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.header.js",
            "value": "",
            "children": {}
        },
        "de.mikromedia.header.html": {
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.header.html",
            "value": "",
            "children": {}
        },
        "dmx.webclient.color#de.mikromedia.font.color": {
            "id": -1,
            "uri": "",
            "typeUri": "dmx.webclient.color",
            "value": "",
            "children": {}
        },
        "de.mikromedia.button": [{
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.button",
            "value": "",
            "children": {
                "de.mikromedia.button.title": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.button.title",
                    "value": "",
                    "children": {}
                },
                "de.mikromedia.button.style": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.button.style",
                    "value": "",
                    "children": {}
                },
                "de.mikromedia.link": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.link",
                    "value": "",
                    "children": {}
                }
            }
        }],
        "de.mikromedia.header.title": {
            "id": 2265,
            "typeUri": "de.mikromedia.header.title",
            "value": "My Header",
            "children": {}
        },
        "dmx.webclient.color#de.mikromedia.background.color": {
            "id": -1,
            "uri": "",
            "typeUri": "dmx.webclient.color",
            "value": "",
            "children": {}
        }
    }
}
        at systems.dmx.core.impl.AccessLayer.createTopic(AccessLayer.java:139)
        at systems.dmx.core.impl.CoreServiceImpl.createTopic(CoreServiceImpl.java:132)
        at systems.dmx.core.impl.CoreServiceImpl.createTopic(CoreServiceImpl.java:34)
        at systems.dmx.webservice.WebservicePlugin.createTopic(WebservicePlugin.java:120)
        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$1.invoke(JavaMethodInvokerFactory.java:60)
        at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
        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.ResourceObjectRule.accept(ResourceObjectRule.java:100)
        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:1480)
        at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1411)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1360)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1350)
        at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
        at org.apache.felix.http.base.internal.handler.ServletHandler.doHandle(ServletHandler.java:339)
        at org.apache.felix.http.base.internal.handler.ServletHandler.handle(ServletHandler.java:300)
        at org.apache.felix.http.base.internal.dispatch.ServletPipeline.handle(ServletPipeline.java:93)
        at org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:50)
        at org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:31)
        at org.apache.felix.http.base.internal.dispatch.FilterPipeline.dispatch(FilterPipeline.java:76)
        at org.apache.felix.http.base.internal.dispatch.Dispatcher.dispatch(Dispatcher.java:49)
        at org.apache.felix.http.base.internal.DispatcherServlet.service(DispatcherServlet.java:67)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:684)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:501)
        at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:229)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:428)
        at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
        at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:255)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
        at org.eclipse.jetty.server.Server.handle(Server.java:370)
        at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:494)
        at org.eclipse.jetty.server.AbstractHttpConnection.content(AbstractHttpConnection.java:982)
        at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.content(AbstractHttpConnection.java:1043)
        at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:865)
        at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:240)
        at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:667)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.RuntimeException: Value integration failed, newValues=TopicModelImpl {
    "id": -1,
    "typeUri": "de.mikromedia.header",
    "children": {
        "de.mikromedia.header.js": {
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.header.js",
            "value": "",
            "children": {}
        },
        "de.mikromedia.header.html": {
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.header.html",
            "value": "",
            "children": {}
        },
        "dmx.webclient.color#de.mikromedia.font.color": {
            "id": -1,
            "uri": "",
            "typeUri": "dmx.webclient.color",
            "value": "",
            "children": {}
        },
        "de.mikromedia.button": [{
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.button",
            "value": "",
            "children": {
                "de.mikromedia.button.title": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.button.title",
                    "value": "",
                    "children": {}
                },
                "de.mikromedia.button.style": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.button.style",
                    "value": "",
                    "children": {}
                },
                "de.mikromedia.link": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.link",
                    "value": "",
                    "children": {}
                }
            }
        }],
        "de.mikromedia.header.title": {
            "id": 2265,
            "typeUri": "de.mikromedia.header.title",
            "value": "My Header",
            "children": {}
        },
        "dmx.webclient.color#de.mikromedia.background.color": {
            "id": -1,
            "uri": "",
            "typeUri": "dmx.webclient.color",
            "value": "",
            "children": {}
        }
    }
}, targetObject=null, compDef=null
        at systems.dmx.core.impl.ValueIntegrator.integrate(ValueIntegrator.java:116)
        at systems.dmx.core.impl.AccessLayer.updateValues(AccessLayer.java:863)
        at systems.dmx.core.impl.AccessLayer.createTopic(AccessLayer.java:137)
        ... 54 more
Caused by: java.lang.NullPointerException
        at systems.dmx.core.impl.ValueIntegrator.parentCandidates(ValueIntegrator.java:668)
        at systems.dmx.core.impl.ValueIntegrator.unifyChildTopics(ValueIntegrator.java:604)
        at systems.dmx.core.impl.ValueIntegrator.unifyComposite(ValueIntegrator.java:317)
        at systems.dmx.core.impl.ValueIntegrator.integrateComposite(ValueIntegrator.java:266)
        at systems.dmx

2. Section topic creation

A very similar (same?) error apperas when I want to create a new `Section`` topic using the webclients search/create dialog.

A section is defined in Migration8 of the dmx-webpages module. In Webpages, every "Section" can, among other things, be composed of "Tiles". All details are defined in the following file: See https://github.com/mukil/dmx-webpages/blob/master/src/main/resources/migrations/migration8.json

I then get the following error message.

Jul 31, 2020 11:09:11 AM systems.dmx.core.util.UniversalExceptionMapper logException
SCHWERWIEGEND: Request "POST /core/topic" failed. Responding with 500 (Internal Server Error). The original exception/error is:
java.lang.RuntimeException: Creating topic failed, model=TopicModelImpl {
    "id": -1,
    "typeUri": "de.mikromedia.section",
    "children": {
        "de.mikromedia.section.placement": {
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.section.placement",
            "value": "",
            "children": {}
        },
        "dmx.webclient.color#de.mikromedia.font.color": {
            "id": -1,
            "uri": "",
            "typeUri": "dmx.webclient.color",
            "value": "",
            "children": {}
        },
        "de.mikromedia.tile": [{
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.tile",
            "value": "",
            "children": {
                "dmx.webclient.color#de.mikromedia.font.color": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "dmx.webclient.color",
                    "value": "",
                    "children": {}
                },
                "de.mikromedia.tile.html": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.tile.html",
                    "value": "",
                    "children": {}
                },
                "de.mikromedia.tile.headline": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.tile.headline",
                    "value": "",
                    "children": {}
                },
                "dmx.webclient.color#de.mikromedia.background.color": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "dmx.webclient.color",
                    "value": "",
                    "children": {}
                },
                "de.mikromedia.link": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.link",
                    "value": "",
                    "children": {}
                }
            }
        }],
        "de.mikromedia.section.css_class": {
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.section.css_class",
            "value": "",
            "children": {}
        },
        "de.mikromedia.section.layout": {
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.section.layout",
            "value": "",
            "children": {}
        },
        "de.mikromedia.section.title": {
            "id": 2436,
            "typeUri": "de.mikromedia.section.title",
            "value": "My Section",
            "children": {}
        },
        "dmx.webclient.color#de.mikromedia.background.color": {
            "id": -1,
            "uri": "",
            "typeUri": "dmx.webclient.color",
            "value": "",
            "children": {}
        }
    }
}
        at systems.dmx.core.impl.AccessLayer.createTopic(AccessLayer.java:139)
        at systems.dmx.core.impl.CoreServiceImpl.createTopic(CoreServiceImpl.java:132)
        at systems.dmx.core.impl.CoreServiceImpl.createTopic(CoreServiceImpl.java:34)
        at systems.dmx.webservice.WebservicePlugin.createTopic(WebservicePlugin.java:120)
        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$1.invoke(JavaMethodInvokerFactory.java:60)
        at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
        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.ResourceObjectRule.accept(ResourceObjectRule.java:100)
        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:1480)
        at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1411)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1360)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1350)
        at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
        at org.apache.felix.http.base.internal.handler.ServletHandler.doHandle(ServletHandler.java:339)
        at org.apache.felix.http.base.internal.handler.ServletHandler.handle(ServletHandler.java:300)
        at org.apache.felix.http.base.internal.dispatch.ServletPipeline.handle(ServletPipeline.java:93)
        at org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:50)
        at org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:31)
        at org.apache.felix.http.base.internal.dispatch.FilterPipeline.dispatch(FilterPipeline.java:76)
        at org.apache.felix.http.base.internal.dispatch.Dispatcher.dispatch(Dispatcher.java:49)
        at org.apache.felix.http.base.internal.DispatcherServlet.service(DispatcherServlet.java:67)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:684)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:501)
        at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:229)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:428)
        at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
        at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:255)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
        at org.eclipse.jetty.server.Server.handle(Server.java:370)
        at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:494)
        at org.eclipse.jetty.server.AbstractHttpConnection.content(AbstractHttpConnection.java:982)
        at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.content(AbstractHttpConnection.java:1043)
        at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:865)
        at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:240)
        at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:667)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.RuntimeException: Value integration failed, newValues=TopicModelImpl {
    "id": -1,
    "typeUri": "de.mikromedia.section",
    "children": {
        "de.mikromedia.section.placement": {
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.section.placement",
            "value": "",
            "children": {}
        },
        "dmx.webclient.color#de.mikromedia.font.color": {
            "id": -1,
            "uri": "",
            "typeUri": "dmx.webclient.color",
            "value": "",
            "children": {}
        },
        "de.mikromedia.tile": [{
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.tile",
            "value": "",
            "children": {
                "dmx.webclient.color#de.mikromedia.font.color": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "dmx.webclient.color",
                    "value": "",
                    "children": {}
                },
                "de.mikromedia.tile.html": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.tile.html",
                    "value": "",
                    "children": {}
                },
                "de.mikromedia.tile.headline": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.tile.headline",
                    "value": "",
                    "children": {}
                },
                "dmx.webclient.color#de.mikromedia.background.color": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "dmx.webclient.color",
                    "value": "",
                    "children": {}
                },
                "de.mikromedia.link": {
                    "id": -1,
                    "uri": "",
                    "typeUri": "de.mikromedia.link",
                    "value": "",
                    "children": {}
                }
            }
        }],
        "de.mikromedia.section.css_class": {
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.section.css_class",
            "value": "",
            "children": {}
        },
        "de.mikromedia.section.layout": {
            "id": -1,
            "uri": "",
            "typeUri": "de.mikromedia.section.layout",
            "value": "",
            "children": {}
        },
        "de.mikromedia.section.title": {
            "id": 2436,
            "typeUri": "de.mikromedia.section.title",
            "value": "My Section",
            "children": {}
        },
        "dmx.webclient.color#de.mikromedia.background.color": {
            "id": -1,
            "uri": "",
            "typeUri": "dmx.webclient.color",
            "value": "",
            "children": {}
        }
    }
}, targetObject=null, compDef=null
        at systems.dmx.core.impl.ValueIntegrator.integrate(ValueIntegrator.java:116)
        at systems.dmx.core.impl.AccessLayer.updateValues(AccessLayer.java:863)
        at systems.dmx.core.impl.AccessLayer.createTopic(AccessLayer.java:137)
        ... 54 more
Caused by: java.lang.NullPointerException
        at systems.dmx.core.impl.ValueIntegrator.parentCandidates(ValueIntegrator.java:668)
        at systems.dmx.core.impl.ValueIntegrator.unifyChildTopics(ValueIntegrator.java:604)
        at systems.dmx.core.impl.ValueIntegrator.unifyComposite(ValueIntegrator.java:317)
        at systems.dmx.core.impl.ValueIntegrator.integrateComposite(ValueIntegrator.java:266)
        at systems.dmx.core.impl.ValueIntegrator.integrate(ValueIntegrator.java:108)
        ... 56 more

Jul 31, 2020 11:09:11 AM systems.dmx.core.impl.TransactionFactory$TransactionResourceFilter$2 filter
WARNUNG: ### Rollback transaction of systems.dmx.webservice.WebservicePlugin#createTopic()