[osmosis-dev] Reading PBF without author information fails

[WanMil]

> Hi,
>
> On 04.07.2012 19:42, WanMil wrote:
>> I have another question regarding osmconvert / osmosis PBF reading.
>>
>> osmosis is not able to read pbf files that have no author information
>> (removed with osmconvert africa.osm.pbf --drop-author
>> -o=africa_noauthor.osm.pbf)
>>
>> When reading the africa_noauthor.osm.pbf file with osmosis an
>> IndexOutOfBoundsException is thrown. Is the author information mandatory
>> for osmosis? Is it possible to change that?
> well... Osmosis doesn't care much about authors and it sure does not
> require them AFAIK. However, this is irrelevant, as the exception is not
> thrown by Osmosis. It is thrown by the PBF deserialization library,
> which is not even part of Osmosis.
>
> Given the stack trace that you kindly provided:
>
>> java.lang.IndexOutOfBoundsException: Index: 0
>>         at java.util.Collections$EmptyList.get(Unknown Source)
>>         at crosby.binary.Osmformat$DenseInfo.getUid(Osmformat.java:3026)
>> [...]
>
> you can see that the exception is thrown in crosby.binary.Osmformat.
> This class is autogenerated by the protobuf compiler from the format
> description (namely osmformat.proto). The exception is thrown when
> parsing a DenseInfo message. This is defined as follows:
>
> message DenseInfo {
>     repeated int32 version = 1 [packed = true];
>     repeated sint64 timestamp = 2 [packed = true]; // DELTA coded
>     repeated sint64 changeset = 3 [packed = true]; // DELTA coded
>     repeated sint32 uid = 4 [packed = true]; // DELTA coded
>     repeated sint32 user_sid = 5 [packed = true]; // String IDs for
> usernames. DELTA coded
>     repeated bool visible = 6 [packed = true];
> }
>
> The user id is indeed optional ("repeated" means zero or more times), so
> there _can_ be valid OSM PBFs that have no author information - if they
> are properly encoded.
>
> Given that the exception is thrown in generated code which deals with
> pure deserialization, I strongly suspect that your input PBF is somehow
> broken. Which means this --drop-author business in osmconvert is
> suspicious. Which means that you should talk to Marqqs about the problem :)
>
> BTW, did you try feeding this noauthor PBF into osmium? If you did, what
> was the result?
>
> In the meantime, may I suggest a workaround for the task at hand:
>
>    osmosis --read-pbf africa.osm.pbf --write-pbf africa-noauthor.osm.pbf
> omitMetadata=true
>
> drops the author just as well (along with other non-essential stuff) :)
> Or is there something wrong with that?
>
> Greetings from Stuttgart
> Igor


Igor,

thanks for your detailed answer. Sounds very reasonable to me. I've 
forwarded your answer to the osmconvert developer.

Have fun!
WanMil