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https://issues.apache.org/jira/browse/AVRO-941?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13134406#comment-13134406
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Doug Cutting commented on AVRO-941:
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> the patch should probably only substitute the namespace field specifically
That's a flaw, but probably not the most critical one. Avro identifiers cannot
contain dots except in namespaces. So as long as the package name contains a
dot (which most do) then the global replace should not harm the schema. Fixing
this requires a fair amount of code, walking the schema and creating a copy
with things renamed. (We already do this in a few places, so probably we
should create a SchemaVisitor API to simplify this, but that's a separate
issue.)
Note that this approach will always be flawed, since it won't always be able to
perfectly reconstruct the relocations used when shading. However replacement
is only attempted when things are already broken, so it does no harm and
imperfections are thus tolerable.
Probably the biggest flaw of the current patch is that it will fails if nested
schemas are not all in the same namespace. To address this we might look for a
common suffix or prefix in the new and old package and then replace the
differing text. For example, if the current class is
com.baz.hidden.org.foo.Bar and the schema is org.foo.Bar then the replacement
should be to prefix all namespaces with com.baz.hidden.
I'd be happy to see such improvements to this patch, but I'd not object to it
being committed more-or-less as-is since it does no harm.
> Avro should support the Apache Maven Shade plugin class relocation feature
> --------------------------------------------------------------------------
>
> Key: AVRO-941
> URL: https://issues.apache.org/jira/browse/AVRO-941
> Project: Avro
> Issue Type: Improvement
> Components: java
> Affects Versions: 1.5.4
> Reporter: Matt Massie
> Attachments: shade.patch
>
>
> The Apache shade plugin allows maven builds to create an uber jar that
> contains dependencies in the project. In addition, the shade plugin allows
> you to relocate dependencies into a private namespace to prevent class
> conflicts on shared class paths. Avro does not support relocation.
> All generated Avro objects contain a string field named SCHEMA$ which serves
> as the authority for the class namespace. When the shade plugin updates the
> byte code to relocate the class, it doesn't alter the SCHEMA$ string. This
> break Avro use of reflection since the namespace in SCHEMA$ points to an
> incorrect location.
> I spoke with Doug about the issue and he was kind enough to provide a quick
> hack in order to fix this issue. The hack is to check for mismatches between
> the byte code and the SCHEMA$ and, when they don't match, to defer to the
> byte code. I'll attach Doug's patch to this Jira.
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