Github user aledsage commented on the issue:
https://github.com/apache/brooklyn-server/pull/339
@sjcorbett observed in https://github.com/apache/brooklyn-server/pull/317
that io.swagger pulls in 2.4.5 of dataformat-jackson-dataformat-yaml etc.
@neykov said:
```
That's a good spot @sjcorbett. The jackson library version mix seems
important.
I think it's better to stick to the same version (even if higher than
required
for swagger), than to risk incompatibility. It's higher risk to use two
parts
of the library with different versions than upgrade all of them.
Another reason to upgrade everything is that in Karaf we are explicitly
adding
the dependencies and pinning them to the fasterxml.jackson.version. This
causes
the classic distribution to have a different mix of jars than the karaf one
-
best to keep them consistent.
```
---
Even in karaf, when using brooklyn-tosca-karaf-init, we'll get the same mix
of class versions: jackson-datatype-joda-2.4.5.jar along with the
jackson-annotations bundle version 2.7.5.
I'm not sure how safe that version mix is. But I'm also not sure how safe
it is to upgrade `datatype-jackson-datatype-joda` etc to 2.7.5 (e.g. will that
be binary compatible with swagger 2.4.5, or will it break in any code paths?).
The options seem to be:
1. Reject this PR (and force downstream projects to figure out how to cope
with Brooklyn using an old version of jackson-core).
2. Just upgrade jackson to 2.7.5 (as proposed in this PR): trust our QA,
and trust jackson to be doing semantic versioning.
3. Build a custom swagger-core 1.5.6 OSGi bundle, so it depends on exactly
jackson 2.4.5 (and thus have both versions safely available in Karaf)
And we could also optionally:
4. Have brooklyn-tosca-karaf-init also bundle `jackson-core-2.4.5.jar`
Option (3) sounds horrible.
Option (1) passes the pain onto downstream projects. Even if using Karaf,
if that downstream project was to cause jackson-core 2.7.5 bundle to be
included in Karaf, then swagger would immediately pick it up instead (because
it depends on import version `[2.4,3)`). It could try including the jars in the
OSGi bundle's `Bundle-ClassPath`, but that's annoying to have to do!
I'd be willing to risk option (2) and merge this as-is, given we've tested
it. Also swagger have declared jackson dependency as `[2.4,3)` so hopefully it
means they trust jackson compatibility!
I hate figuring out the right dependency versions!
---
Investigating the dependencies,
`brooklyn-dist/dist/target/brooklyn-dist/brooklyn` has:
```
./lib/brooklyn/com.fasterxml.jackson.core-jackson-annotations-2.7.5.jar
./lib/brooklyn/com.fasterxml.jackson.core-jackson-core-2.7.5.jar
./lib/brooklyn/com.fasterxml.jackson.core-jackson-databind-2.7.5.jar
./lib/brooklyn/com.fasterxml.jackson.dataformat-jackson-dataformat-xml-2.4.5.jar
./lib/brooklyn/com.fasterxml.jackson.dataformat-jackson-dataformat-yaml-2.4.5.jar
./lib/brooklyn/com.fasterxml.jackson.datatype-jackson-datatype-joda-2.4.5.jar
./lib/brooklyn/com.fasterxml.jackson.jaxrs-jackson-jaxrs-base-2.7.5.jar
./lib/brooklyn/com.fasterxml.jackson.jaxrs-jackson-jaxrs-json-provider-2.7.5.jar
./lib/brooklyn/com.fasterxml.jackson.module-jackson-module-jaxb-annotations-2.7.5.jar
```
Whereas `brooklyn-dist/karaf/apache-brooklyn/target/assembly` has:
```
./system/com/fasterxml/jackson/core/jackson-annotations/2.7.5/jackson-annotations-2.7.5.jar
./system/com/fasterxml/jackson/core/jackson-core/2.7.5/jackson-core-2.7.5.jar
./system/com/fasterxml/jackson/core/jackson-databind/2.7.5/jackson-databind-2.7.5.jar
./system/com/fasterxml/jackson/dataformat/jackson-dataformat-yaml/2.7.5/jackson-dataformat-yaml-2.7.5.jar
./system/com/fasterxml/jackson/jaxrs/jackson-jaxrs-base/2.7.5/jackson-jaxrs-base-2.7.5.jar
./system/com/fasterxml/jackson/jaxrs/jackson-jaxrs-json-provider/2.7.5/jackson-jaxrs-json-provider-2.7.5.jar
```
Looking at a downstream karaf that also bundles the `brooklyn-tosca`
feature (with the bundle `brooklyn-tosca-karaf-init/0.10.0-SNAPSHOT`), the
system dir has:
```
./system/com/fasterxml/jackson/core/jackson-annotations/2.4.5/jackson-annotations-2.4.5.jar
./system/com/fasterxml/jackson/core/jackson-annotations/2.7.5/jackson-annotations-2.7.5.jar
./system/com/fasterxml/jackson/core/jackson-core/2.4.5/jackson-core-2.4.5.jar
./system/com/fasterxml/jackson/core/jackson-core/2.7.5/jackson-core-2.7.5.jar
./system/com/fasterxml/jackson/core/jackson-databind/2.4.5/jackson-databind-2.4.5.jar
./system/com/fasterxml/jackson/core/jackson-databind/2.7.5/jackson-databind-2.7.5.jar
./system/com/fasterxml/jackson/dataformat/jackson-dataformat-yaml/2.4.5/jackson-dataformat-y
