Re: BUG #18943: Return value of a function 'xmlBufferCreate' isdereferenced at xpath.c:177 without checking for NUL

Hello Michael,

Maybe you would like to fix in passing one more anomaly there:
create extension xml2;
select xslt_process('<aaa/>','<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"></xsl:stylesheet>');

leads to:
varlena.c:199:2: runtime error: null pointer passed as argument 2, which is declared to never be null
     #0 0x640756666936 in cstring_to_text_with_len .../src/backend/utils/adt/varlena.c:199
     #1 0x7e46c0f4805e in xslt_process .../contrib/xml2/xslt_proc.c:149
     #2 0x640755a3ecbf in ExecInterpExpr .../src/backend/executor/execExprInterp.c:1001
     #3 0x640755a277aa in ExecInterpExprStillValid .../src/backend/executor/execExprInterp.c:2299
     #4 0x640755ef11e0 in ExecEvalExprSwitchContext ../../../../src/include/executor/executor.h:444
     #5 0x640755efd7b6 in evaluate_expr .../src/backend/optimizer/util/clauses.c:5724

for a build made with -fsanitize=undefined.

Best regards,
Alexander