W3C home > Mailing lists > Public > www-validator@w3.org > September 2013

Re: Cannot recover after last error

From: Michael[tm] Smith <mike@w3.org>
Date: Mon, 30 Sep 2013 13:25:05 +0900
To: Jaime Iniesta <jaimeiniesta@gmail.com>
Cc: "www-validator@w3.org" <www-validator@w3.org>
Message-ID: <20130930042503.GM2488@sideshowbarker>
Hi Jaime,

Jaime Iniesta <jaimeiniesta@gmail.com>, 2013-09-29 20:37 +0200:

> Is there a measure of the performance boost we get when working on
> streaming mode?

No. But regardless, it's not just about the performance.

> Is it worth not being able to fully validate many documents?

For case of the service that I maintain, it's worth it for its behavior to
be fully streaming. For anybody running a separate service, I think it's up
to them to decide how they'd prefer to run it.

And it's not a matter of the service not being able to "fully validate many
documents". For all cases where it stops checking the subtree, there is
always an absolute error in the document that should be corrected. Once that
error is corrected, the user can then revalidate that document and the rest
of the subtree will be checked. That does not seem to me to be a bad thing.

> Don't take http://validationhell.com for more than what it is: a site
> intentionally invalid to test validators, but consider that real sites out
> there have this same kind of errors, they can't be fully validated because
> of this streaming mode.

They can be fully validated. It just requires more that one pass through the
validator, after the user makes initial corrections to remove those errors.

> For example, http://twitter.com
> 
> http://validator.w3.org/nu/?doc=http%3A%2F%2Ftwitter.com
> 
> And a Google search for the "Cannot recover for the last error"... message
> throws more than 200K results:
> 
> https://www.google.com/search?q=%22cannot+recover+after+last+error.+any+further+errors+will+be+ignored%22

I don't find those results at all surprising.

> I think that, as Validator.nu would be able to validate those documents in
> non-streaming mode, a good solution would be first trying the streaming
> mode, and, if this particular error happens, retry in non-streaming mode.

I think I'd rather not experiment with changing the behavior of the
production service in this regard for something I'm not at all convinced
provides actual net benefits. If someone would like to try it with another
instance and come back with data to talk about, that'd be great.

> If Validator.nu can't be fixed

It's not broken and doesn't need to be fixed. It's operating this way by
design, not by mistake.

> so it can fully validate documents,

Again, it can fully validate any document. The fact that it may require the
user to correct some errors and then re-validate it is not a hardship.

> then I think having a clearer error message would help.

If you have specific suggestions for such a message, please let me know.

> Something that would include that it couldn't recover after the last
> error because of the streaming mode.

OK, I guess I could put something in there like, "Cannot continue after
last error because it requires non-streaming error recovery."

> Anyway, just my 2 cents about improving the validator.

Thanks for the feedback and sorry if I've sounded defensive here, but I
hope you can appreciate that some thought has already gone into this and
the current behavior is a well-considered decision and there is not broken
behavior here that needs to be fixed.

  --Mike

-- 
Michael[tm] Smith http://people.w3.org/mike
Received on Monday, 30 September 2013 04:25:15 UTC

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