Use the filehook package instead of scrlfile about xsim

[cgnieder]

This is most likely an issue of the filehook package. The new LaTeX kernel (2019.10.16) changed the definition of \InputIfFileExists and scrlfile (scrlfile 2019/10/12 v3.27) adapted its definitions accordingly. filehook-scrlfile is still 2011/01/03 v0.1 and hasn't adapted its definitions. Since filehook seems to be actively maintained (the current version is 2019/10/03 v0.6) this should rather be addressed there…

[pablgonz]

A thousand apologies, when I wrote this had not been updated scrlfile :)

[cgnieder]

I believe you misunderstood me. There is an error with an up to date system. But the fix should be made in the filehook package and not in xsim.

[pablgonz]

Now I understand you, anyway you are right, I expressed myself wrongly, is a problem of the package filehook, the strange thing is that I get the message only when using unicode-math, in my mind I believed that xsim only used l3 packages and not law nor I noticed before I loaded scrlfile with which I am not very familiar (I have never used KOMA).
As a closing comment, it's not a good idea to reinvent the wheel, but, you can avoid using scrlfile using only expl3?
Thank you for taking the time to respond.

[pablgonz]

latex will change definition of \InputIfFileExists and this breaks filehook