range:index-keys-for-field with dynamic context only works correctly when wrapped inside dynamic function call

[olvidalo]

range:index-keys-for-field("some-field", function($key, $nums) { $key }, 10)`

✅ returns all keys for some-field for the statically known documents.

collection("/db/some-collection/")/range:index-keys-for-field("some-field", function($key, $nums) { $key }, 10)`

❌ will evaluate the function for each document in the collection instead of for the context document set at once, so it returns the keys multiple times for each document instead of once for the collection

let $func := function-lookup(xs:QName("range:index-keys-for-field"), 3) 
return  collection("/db/some-collection/")/$func("some-field", function($key, $nums) { $key }, 10)

✅ however, wrapping it inside a dynamic function will make it work

let $func := function($a, $b, $c) {
    range:index-keys-for-field($a, $b, $c)
}

return  collection("/db/some-collection/")/$func("some-field", function($key, $nums) { $key }, 10)

✅ also works

declare function local:func($a, $b, $c) {
  range:index-keys-for-field($a, $b, $c )  
};

return  collection("/db/some-collection/")/local:func("some-field", function($key, $nums) { $key }, 10)

❌ does not work

It might have something to do with the expression dependencies being incorrectly set at one point down the stack (the evaluation path leading to the incorrect results seems to start in PathExpr.eval() when the expression's dependencies are determined) but as I have no idea what I'm actually talking about I'll leave it at that for the time being...

There'll be a pull request with a test coming in shortly

[dizzzz]

did you test this with eXist-db 3.0RC2/develop ?

[olvidalo]

Tested it with the current develop commit

[duncdrum]

if the test is passing, this seems to be fixed?