[wildfly-dev] Pretty-printing XML validation errors

[Toby Crawley]

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.

> Personally I think it’s ok to have this for only some failures. Others may
> disagree though and start filing bug reports, leading to demands that we fix
> said “bugs”, leading to a shift of resource away from other tasks.
>
> My instinct is it’s worth it though. I’m curious what others think.
>

Adding more to the WildFly team's plate is a concern of mine as well.
I'm willing to do the work to finish this feature, and to help out
with any reported issues related to it in the future, but there would
still be some increase in the team's workload from it.

> I think the path you’ve followed is a good way to get a lot of benefit
> without being overly intrusive.
>
> A medium sized concern is this has to be robust. It can’t be producing
> misleading messages, as that’s worse than simply pointing to the line/col of
> where the mistake was.
>

Agreed - there needs to be some confidence level that if the tool
can't meet for an error, it falls back to just pointing to the
line/col, printing the original message. I fact, that may be good
enough for the failures that bubble out of staxmapper as well.

> 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.

> Re: "Only the first validation issue is reported, but this is unavoidable,
> since the subsystem parsers throw on the first error encountered” — I’m not
> bothered by that at all. We’re booting a server, not validating a document.
> If people are producing documents riddled with errors there are other tools
> to use to help with that.

Makes sense, thanks.