Hi Michael,
{"type":"record","name":"AliasReferenceExample","fields":[{"name":"anEnum","type":{"type":"enum","name":"exampleEnum","alias":"1
> bad alias","symbols":["A","B","C"]}},{"name":"anotherEnum","type":"1
> bad alias"}]}
>
In the current Java binding, the namespace portion in an alias is accepted
without validation.
So, the following schema is acceptable.
{"type":"record","name":"AliasReferenceExample","fields":[{"name":"anEnum","type":{"type":"enum","name":"exampleEnum","alias":"1bad
alias.foo.bar","symbols":["A","B","C"]}},{"name":"anotherEnum","type":"exampleEnum"}]}
I'm discussing namespace in this thread, so this behavior seems O.K to me.
But reference to another named types is not implemented for the Java
binding.
So the following schema is not accepted.
{"type":"record","name":"AliasReferenceExample","fields":[{"name":"anEnum","type":{"type":"enum","name":"exampleEnum","alias":"1bad
alias.foo.bar","symbols":["A","B","C"]}},{"name":"anotherEnum","type":"1bad
alias.foo.bar"}]}
I have a plan to fix it.
2023年8月18日(金) 11:33 Michael A. Smith <[email protected]>:
> I found I'm still a little confused at how using aliases to correct
> invalid names should work. Maybe you can define an alias that is an
> invalid name, but having done so, can you use it? I tried this schema
> in both the Python and Java implementations.
>
>
> {"type":"record","name":"AliasReferenceExample","fields":[{"name":"anEnum","type":{"type":"enum","name":"exampleEnum","alias":"1
> bad alias","symbols":["A","B","C"]}},{"name":"anotherEnum","type":"1
> bad alias"}]}
>
> I expected it to error in Python, because I know Python requires valid
> names for aliases. But Java also errored with "schema failed: Illegal
> initial character: 1 bad alias". I am not sure if the error is from
> the alias definition or its use.
>
> If my example is flawed, can someone supply a correct one?
>
> On Thu, Aug 17, 2023 at 4:53 AM Oscar Westra van Holthe - Kind
> <[email protected]> wrote:
> >
> > On Mon, 14 Aug 2023 at 14:11, Ryan Skraba <[email protected]> wrote:
> >
> > > I think the right thing to do is [to] use a system
> > > property / schema aliases to help people migrate back to the correct
> > > behaviour. If you are actually using Avro/Protobuf together, you
> > > might be the best person to help us figure out the right was to do
> > > this migration!
> > >
> >
> > The idea that aliases can be used to evolve a schema with invalid names
> to
> > a schema with valid names is a sensible one, and currently hidden in the
> > schema resolution rules in the specification.
> >
> > I've added AVRO-3833 <https://issues.apache.org/jira/browse/AVRO-3833>
> (with
> > PR <https://github.com/apache/avro/pull/2448>) because I wanted to
> clarify
> > that names must
> > be unique (because otherwise schema resolution cannot work), and that
> this
> > includes aliases. The change also includes this migration/fix option.
> >
> > Kind regards,
> > Oscar
> >
> > --
> > ✉️ Oscar Westra van Holthe - Kind <[email protected]>
>
