[BUG] File handler being closed by UserDefinedFunction

[marmoure]

If we pass a file handler to a UserdefinedFunction the file handler will be closed once the call is done, even though it still needed for the rest of the code.

how to reproduce

1. Create a test file echo "hello" > /tmp/file
2. Run this script

xquery version "3.1";
declare namespace file = "http://exist-db.org/xquery/file";
declare function local:noop($b) { 1 };

let $b := file:read-binary("/tmp/file")

let $tmp := local:noop($b)

(: no longer accessible:)
return string($b)

results

We get Underlying channel has been closed

expected

We should get the string value of the file.

This issue is similar to eXist-db/exist#6725 but we are sure it's not coming from the same origin.