opam switch link breaks existing _opam switches

[mattam82]

When doing an opam switch link (erroneously) on an already existing _opam switch, it seems to entirely break the existing switch, there's no error message or anything, as far as I can tell. It happens to me from time to time and should be prevented entirely I think.

[kit-ty-kate]

What version of opam are you using? Your problem seems to be similar to #6449, which has been fixed in opam 2.4.0 released last year

[rjbou]

The test in #6860 shows that last opam version has the good behaviour.