xslt error logs are gone since 2012

[Marcus Brinkmann]

Hi,

I finally debugged a problem that locked us on lxml 2.3.5: xslt errors where spuriously absent from the error log in some situations. Turns out that revision 850144 "efactored error log connection into a context manager, added support for recursive usage of different logs" (Apr 7 14:51:20 2012) by Stefan Behnel broke this, because it only registers an xml error handler and not the one for xslt.

The attached patch fixes this, in addition to adding a test case for it.

[scoder (scoder)]

I applied your patch and repaired it here:

https://github.com/lxml/lxml/commit/079c1d452d0f0ae3826b73f59b6fd6a9b9d5dcf3

[Marcus Brinkmann (m-brinkmann)]

Very cool, thanks a lot!

On 03/18/2016 08:19 PM, scoder wrote:
> I applied your patch and repaired it here:
>
> https://github.com/lxml/lxml/commit/079c1d452d0f0ae3826b73f59b6fd6a9b9d5dcf3
>
>
> ** Changed in: lxml
> Importance: Undecided => Medium
>
> ** Changed in: lxml
> Status: New => Fix Committed
>
> ** Changed in: lxml
> Milestone: None => 3.6.1
>

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[Vojtěch Fried (vojtechfried)]

Hi,
this fix actually broke lxml for me. We are using lxml in multiple threads. Unfortunately, unlike the libxml2 version (xmlSetGenericErrorFunc), the libxslt version (xsltSetGenericErrorFunc) is not thread safe, but is a global. So it cannot be safely used in multithreaded scenarios. Unless it is fixed in libxslt, the best thing to do in lxml is I think to make a build switch that would turn xsltSetGenericErrorFunc off.

[scoder (scoder)]

Since the previous fix breaks multi-threaded processing, I reverted it.

[scoder (scoder)]

Here's a new fix (latest master branch) that hopefully solves both problems.
https://github.com/lxml/lxml/commit/d6fdeee94084e172bb81cf92119a081362f0dbcf