I don't understand teh probelm. What is it ? where ? what's the
symptoms. You just can't drop an example at me without any explanation !

Daniel

[Note: This was posted about one month ago on the XSLT List. I repeat it 
here so its linked with the case.] 
 
I have the same problem as Mr. Tom Moertel. I've created a test-case 
which documents the behavior. The test case is 600KB and can be 
downloaded at http://www.philmann-dark.de/xslt-bug1.tar.gz (and yes, I 
stripped the test to the smallest possible size). 
 
Just get the file, unpack it (it creates a new directory), go into xslt-bug1 and 
run "./run". 
 
It will run two tests. The first one in test.xsl works. It says: 
 
... 
exsltFuncRegisterFunc: register {my://own.uri}lookup-image-info 
Registered module http://exslt.org/functions 
... 
xsltCopyOf: select my:lookup-image-info('animation/jei-ani.gif') 
Lookup function {my://own.uri}lookup-image-info 
found function lookup-image-info 
... 
 
The second test prints the same but when I use the function, I suddenly 
get: 
 
... 
Lookup function {my://own.uri}lookup-image-info 
xmlXPathCompOpEval: function lookup-image-info not found 
XPath error Unregistered function in my:lookup-image-info($path-key) 
runtime error: file image-common.xsl line 173 element variable 
Evaluating variable info failed 
call-template returned: name insert-img 
 
On a related note, global variables sometimes get lost (ie. I can see that 
the lookup of them works 20 times and then xsltproc crashes while trying to 
look it up once more). 
 
My guess is that there is a buggy pointer somewhere (memory overwritten, 
freed twice, etc). This is why the simple example works but the complex 
one fails and why I couldn't strip the test down further. 
 
I've submitted a bug report in bugzilla (#114812). 
 
Since this a pretty urgent issue for me, I'm willing to help to track this bug 
down if anyone can tell me what other things I should try. 
 
Note that this is not like Bug #114377! In my case, the function isn't even 
called! 

Well the use of the exslt:function extension do give troubles ...

I tried to check the memory accesses, nothing strange is reported
by valgrind:

==25981==
==25981== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
==25981== malloc/free: in use at exit: 4096 bytes in 1 blocks.
==25981== malloc/free: 665119 allocs, 665118 frees, 46000894 bytes
allocated.
==25981== For a detailed leak analysis,  rerun with: --leak-check=yes
==25981== For counts of detected errors, rerun with: -v

  the differences between the test which works and the one which 
doesn't is quite significant:

paphio:~/tmp/xslt-bug1 -> diff comic2html.xsl test.xsl | wc -l
    305
paphio:~/tmp/xslt-bug1 -> diff dummy.xml tmp/data.xml | wc -l
  31643

  How I am supposed to analyze the difference which leads one to
success and the other to failure ?

  If you want to help do the same as I would have to do:
  1/ run xsltproc under a debugger
  2/ breakpoint in the exslt extension function routine
  3/ run the transformation 
  4/ check that the function is correctly registered
  5/ continue until you breakpoint a the precise moment
     where the function is looked for
  6/ check why the lookup fails

  you may have to find when in 5 the pointer got removed.
This is extremeley time consuming especially since the transformation
is large. 

Daniel

How do I do step 4? In which global data structure should the function 
appear? In which function does this happen? 
 
As I understand, all these things are stored in hashes which have the 
structure table->table[key]->next->next->...->NULL 
 
If I knew where my function is added, then I could add a watch for the next 
pointer pointing to the entry of my function: 
 
(gdb) p table->table[0]->next 
$45 = (struct _xmlHashEntry *) 0x804ee00 
(gdb) watch *(int *)0x804ee00 
Hardware watchpoint 9: *(int *) 134540800 
(gdb) 
 
Then GDB will stop when this pointer is changed. 
 
I've found that exsltFuncFunctionComp() registers my function but it adds it 
only to a hash with one single entry. I guess that it is then copied to a 
global hash but I'm at a loss where that could be. 
 
Also, why is xmlXPathRegisterFuncNS() only called for lookup-char but not 
for lookup-image-info? 
 
Maybe the function is not registered globally? 

I have no idea, I didn't wrote that code. I think this need to be 
posted on the mailing-list (not DocBook one, libxml one).

Daniel

The problem concerning the exslt function was caused by a bug in the 
code handling importing stylesheets.  I was able to produce test 
cases of a few tens of lines which demonstrated it (trying to debug 
a test case such as was initially submitted is completely 
impractical).

The fixes are in CVS.  Please check that they fix all of your 
problem.

Yep, now it works! Thanks a million for the quick fix! :-)