[wildfly-dev] Pretty-printing XML validation errors

[Toby Crawley]

On Tue, Jul 19, 2016 at 4:07 PM, Brian Stansberry
<brian.stansberry at redhat.com> wrote:
> Comments in-line, except for something I just thought of.
>
> All exception and log messages produced will likely need to follow
> WildFly’s/EAP's i18n standards. Message prefixed with a code, text produced
> in a way in an i18n manner with a reasonable way to get localized text into
> the software.

Ah, good point. It shouldn't be difficult to add localized text to the
output, the biggest cost there would be the time to translate the
messages, but I'm not familiar with how i18n is done in our projects.
For the message code, we could print the original exception message at
the bottom or top of the validation block. That would then use the
same code as we provide now, and would provide the same message we use
now with every error. Would that satisfy the message code requirement?

>>
>> On Jul 19, 2016, at 2:38 PM, Toby Crawley <tcrawley at redhat.com> wrote:
>>
>>> On Tue, Jul 19, 2016 at 3:15 PM, Brian Stansberry
>>> <brian.stansberry at redhat.com> wrote:
>>>
>>> The only big concern I have about this is that we’ll get this behavior for
>>> some failures but not all. And I don’t want to go down the path of trying to
>>> force every parser to work in a manner such that we consistently get this.
>>>
>>
>> I haven't looked at it too deeply, but it may be straightforward to
>> alter staxmapper to allow providing an exception generator that would
>> allow catching more of the cases that the parsers miss.
>>
>
> I’m not sure how big of a problem staxmapper-thrown exceptions are. (I
> haven’t really thought.)

That's just the first place I saw errors from outside of ParseUtils,
but I haven't yet started playing with attribute values.

>
> What I was thinking more about when I wrote my previous post was parsers not
> using ParseUtils, or sometimes not using it.
>
> Also, a lot of XmlStreamException cases are generated from implementations
> of org.jboss.as.controller.AttributeDefinition, e.g.
>
> https://github.com/wildfly/wildfly-core/blob/master/controller/src/main/java/org/jboss/as/controller/SimpleAttributeDefinition.java#L140
>
> Parsers are encouraged to invoke methods on AttributeDefinition to validate
> attribute values. Perhaps though those are better left alone, as the
> validators are meant to produce useful exception messages.
>

If we let these fall back to just pointing out the error location with
the original message, this may be ok (assuming by "the alidators are
meant to produce useful exception messages" you mean the messages
produced by the AttributeDefinitions).

<snip>

>>> A minor concern is how big the added dependencies are. (I don’t know.) We
>>> want to keep WildFly Core small in footprint.
>>>
>>
>> Right now, the only dependencies vdx (31k) has are commons-lang (which
>> is already a module in WildFly, but not core-feature-pack),
>> xmlschema-walker (100k), and xmlschema-core (168k). For the rest of
>> the work, I don't currently see needing any more dependencies.
>>
>
> Thanks. So about 583K including 284K for commons-lang. The current
> wildly-core-dist-3.0.0.Alpha3.zip is about 16.9MB, so this is fairly
> substantial.
>

I'm only using commons-lang for a Levenshtein distance implementation
- that could certainly be pulled in, and we could drop the 284k for
commons-lang. It certainly would be nice to keep core under 17MB
though.

- Toby