inversion of nothing with --file?

[datatraveller1]

I want to list all found values from a search and all not found values from a search.
The following is a simplified example. The values searched for are listed in the file search_for.txt.

search_for.txt:

1
2
3

The file in which these values are searched is named searched_in.txt.

searched_in.txt:

item 1
item 2

I use the following commands (note that I'm on MS Windows):

find entries of file search_for.txt:

rg --file=search_for.txt --only-matching searched_in.txt > found.txt

not found entries of file search_for.txt:

rg --invert-match --file=found.txt search_for.txt > not_found.txt

The result is correct:

found.txt:

1
2

not_found.txt:

3

Great so far.
However, if I change the content of file search_for.txt so nothing is found...
search_for.txt:

4
5
6

... with the two above commands, the file found.txt gets created as a 0 bytes file (which is correct, because nothing is found) but the file not_found.txt gets also created as a 0 bytes file which doesn't match my expectations.
I have wished to see all values of file search_for.txt as result for the command
rg --invert-match --file=found.txt search_for.txt > not_found.txt
not_found.txt, wished result:

4
5
6

Isn't the inversion of nothing everything?
If this is the expected behaviour, is there a special flag to achieve what I want for --file and 0 bytes content of this file?

[BurntSushi]

I think you stumbled on a bug. Nice find. I filed an issue for it here: #3001

It's probably an easy fix.

[datatraveller1]

Great thank you!
Although I did search the whole repository for similar cases, I obviously missed this one (sorry about that) which describes the same issue:
#1332

[datatraveller1]

Here is my (somewhat ugly 😃) workaround for MS Windows:

rem not found entries of file search_for.txt:
@for %%x in (found.txt) do if %%~zx==0 (
  rem if file size is 0 bytes, add a dummy value so ripgrep can invert matches
  echo [[dummy]]>found.txt
)
rg --invert-match --file=found.txt search_for.txt > not_found.txt

It would be really nice if this could be fixed, though.