[tr064] Duplicate phonebook entries lead to exception

[t2000]

I have encountered this exception with my fritzbox phone book:

2021-01-07 20:58:55.015 [WARN ] [mmon.WrappedScheduledExecutorService] - Scheduled runnable ended with an exception: 
java.lang.IllegalStateException: Duplicate key +4917XXXXXXX (attempted merging values Some Name and Some Name)
        at java.util.stream.Collectors.duplicateKeyException(Collectors.java:133) ~[?:?]
        at java.util.stream.Collectors.lambda$uniqKeysMapAccumulator$1(Collectors.java:180) ~[?:?]
        at java.util.stream.ReduceOps$3ReducingSink.accept(ReduceOps.java:169) ~[?:?]
        at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1655) ~[?:?]
        at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484) ~[?:?]
        at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[?:?]
        at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913) ~[?:?]
        at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[?:?]
        at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578) ~[?:?]
        at org.openhab.binding.tr064.internal.phonebook.Tr064PhonebookImpl.lambda$0(Tr064PhonebookImpl.java:76) ~[?:?]
        at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195) ~[?:?]
        at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1655) ~[?:?]
        at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484) ~[?:?]
        at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[?:?]
        at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913) ~[?:?]
        at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[?:?]
        at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:589) ~[?:?]
        at org.openhab.binding.tr064.internal.phonebook.Tr064PhonebookImpl.getPhonebook(Tr064PhonebookImpl.java:77) ~[?:?]
        at org.openhab.binding.tr064.internal.phonebook.Tr064PhonebookImpl.<init>(Tr064PhonebookImpl.java:58) ~[?:?]
        at org.openhab.binding.tr064.internal.Tr064RootHandler.lambda$21(Tr064RootHandler.java:340) ~[?:?]
        at java.util.Optional.map(Optional.java:265) ~[?:?]
        at org.openhab.binding.tr064.internal.Tr064RootHandler.lambda$20(Tr064RootHandler.java:340) ~[?:?]
        at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195) ~[?:?]
        at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948) ~[?:?]
        at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484) ~[?:?]
        at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[?:?]
        at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913) ~[?:?]
        at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[?:?]
        at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578) ~[?:?]
        at org.openhab.binding.tr064.internal.Tr064RootHandler.processPhonebookList(Tr064RootHandler.java:345) ~[?:?]
        at org.openhab.binding.tr064.internal.Tr064RootHandler.lambda$26(Tr064RootHandler.java:360) ~[?:?]
        at java.util.Optional.map(Optional.java:265) ~[?:?]
        at org.openhab.binding.tr064.internal.Tr064RootHandler.retrievePhonebooks(Tr064RootHandler.java:358) ~[?:?]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) ~[?:?]
        at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305) ~[?:?]
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305) ~[?:?]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
        at java.lang.Thread.run(Thread.java:834) [?:?]

Apparently the problem is that the phonebook is an export from my mobile phone.

My mobile phone has multiple accounts where it creates the full phone book from. There is the phone internal phone book, one from a carddav server, one from telegram, one from signal, etc.

If there people that I have added in the carddav phonebook, apps like telegram will create a copy of this contact in a "telegram phone book". The mobile phone correctly merges these 2 contacts from the 2 accounts back into one for a list for the user to scroll through without seeing duplicates.

However, If I export such a phonebook that contains these multiple accounts I get. And here the part in "()" refers to the type of the entry, so its not part of the name string!:

Firstname LastName (mobile) +49123456789
Firstname LastName (other) +49123456789

The fritzbox understands the fact that one number belongs to "mobile" and one belongs to "other". So this is a valid phonebook for the fritzbox as well.

The problem is the mapping function in Tr064PhonebookImpl.lambda$0(Tr064PhonebookImpl.java:76, it throws the aforementioned exception. And I think it is right when throwing such an exception IFF there are two or more DIFFERENT names for the same number. But it should NOT throw an exception if there are multiple entries for one number, all pointing to the the very same name.