rebis-dev_...: pio: Expected IO interaction or a "spooky action at a distance"?

[haijinSk]

Version:

rebis-dev_opt-in-offset-tbl-concurrency, https://github.com/mthom/scryer-prolog/tree/rebis-dev_opt-in-offset-tbl-concurrency

https://github.com/mthom/scryer-prolog/tree/60695e8cf84be5a10cdec9f6c7333dc8aaadb0e6

Creating an auxiliary file and seeing that the file is empty:

$ touch text.txt
$ cat text.txt 
$ 

A file to consult:

:- use_module(library(pio)).
:- use_module(library(dcgs)).

test :-
  phrase_from_file(seq(Str),"text.txt"),
  writeToEmptyFile(Str).

writeToEmptyFile([_|_]) :-
  write(text_in_file_already),nl.
writeToEmptyFile([]) :-
  write(writing_to_file),nl,
  phrase_to_file(seq("Hello..."),"text.txt").

Is this interaction expected?:

?- test.
writing_to_file
   true
;  text_in_file_already
true
;  false.

With the empty file, intuitively as a naive user, I would expect (as with master or Trealla Prolog) interaction like this:

?- test.
writing_to_file
   true
;  false.

Thank you.

[haijinSk]

PS:

In my test/0 I could use once/1:

test :-
  once(phrase_from_file(seq(Str),"text.txt")),
  writeToEmptyFile(Str).

and then I would have the expected (for me) interaction...

[triska]

This seems unexpected, could you please file this as an issue? Thank you a lot!

[haijinSk]

#2988

Thank you very much for the answer.