[help] XSLT::Stylesheet#transform return infinite template recursion error

[ChrisKaun]

What problem are you trying to solve?

I try to transform the zugferd/factur-x schema file with the xslt2 into a schematron to be able to validate incoming factur-x xml invoices.

Please show your code!

Here is a zip file with the schema file and the iso-schematron-xslt2 files:
files.zip

The 'iso_dsdl_include.xsl' file will raise an error when tranforming.
Example code:

require 'nokogiri'

schema_path = File.join(__dir__, 'Factur-X_1.0.07_EN16931.sch')
schematron_doc = Nokogiri::XML(File.read(schema_path))
xsl_path = File.join(__dir__, 'iso_dsdl_include.xsl')
xsl_file = Nokogiri::XSLT(File.read(xsl_path))
xsl_file.transform(schematron_doc)

=> (irb):7:in `transform': runtime error: element value-of (RuntimeError)
xsltApplySequenceConstructor: A potential infinite template recursion was detected.

FullError:

(irb):7:in `transform': runtime error: element value-of (RuntimeError)
xsltApplySequenceConstructor: A potential infinite template recursion was detected.
You can adjust xsltMaxDepth (--maxdepth) in order to raise the maximum number of nested template calls and variables/params (currently set to 3000).
Templates:
#0 name strip-strings
#1 name strip-strings
#2 name strip-strings
#3 name strip-strings
#4 name strip-strings
#5 name strip-strings
#6 name strip-strings
#7 name strip-strings
#8 name strip-strings
#9 name strip-strings
#10 name strip-strings
#11 name strip-strings
#12 name strip-strings
#13 name strip-strings
#14 name strip-strings
Variables:
#0
mode
string
#1
string
#2
mode
string
#3
string
#4
mode
string
#5
string
#6
mode
string
#7
string
#8
mode
string
#9
string
#10
mode
string
#11
string
#12
mode
string
#13
string
#14
mode
string
        from (irb):7:in `<main>'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/irb-1.4.1/exe/irb:11:in `<top (required)>'
        from /home/.../.rbenv/versions/3.1.2/bin/irb:25:in `load'
        from /home/.../.rbenv/versions/3.1.2/bin/irb:25:in `<top (required)>'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/cli/exec.rb:58:in `load'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/cli/exec.rb:58:in `kernel_load'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/cli/exec.rb:23:in `run'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/cli.rb:455:in `exec'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/vendor/thor/lib/thor/command.rb:28:in `run'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/vendor/thor/lib/thor/invocation.rb:127:in `invoke_command'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/vendor/thor/lib/thor.rb:527:in `dispatch'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/cli.rb:35:in `dispatch'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/vendor/thor/lib/thor/base.rb:584:in `start'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/cli.rb:29:in `start'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/exe/bundle:28:in `block in <top (required)>'
        from /home/.../.rbenv/versions/3.1.2/lib/ruby/gems/3.1.0/gems/bundler-2.5.22/lib/bundler/friendly_errors.rb:117:in `with_friendly_errors'
        ... 3 levels...

Environment

• nokogiri 1.16.7
• ruby 3.1.2
• ubuntu 20.04

Additional context
I tried to adapt the codebase of the nokogiri-schematron gem (https://github.com/alexxed/schematron) which wasn't updated in ~8 years.

[flavorjones]

@ChrisKaun Thanks for asking this question.

Nokogiri doesn't currently support Schematron, although libxml2 itself does. I honestly don't know much about Schematron, and have never used it myself. Can you explain a bit more about what this code snippet is supposed to do? Can you say more about why you aren't using the gem that you mention (it seems like it still passes its test suite with modern Nokogiri)?