bug#58525: 28.1: `vc-dir' (key sequence: C-x v d) fails when used with a CVS repository

[Dmitry Gutov]

On 18.10.2022 04:06, Mark Harig wrote:
> To reproduce the problem, create a ~/.git/ directory and then
> follow the recipe in the original problem report.  Those steps
> take less than 10 minutes to reproduce the problem, using Emacs
> 28.1, bash, and cvs.  Please let me know if those steps do not
> reproduce the problem with Emacs 28.1.

When I tried to follow your steps (not in HOME toplevel, though, but in 
a subdirectory), I got this:

Debugger entered--Lisp error: (wrong-type-argument sequencep t)
  #f(compiled-function (d1 d2) #<bytecode -0xaf17ad190f8dc52>)((Git . 
"~/examples/emacs-debbugs-58525/") (CVS . t))
  sort(((CVS . t)) #f(compiled-function (d1 d2) #<bytecode 
-0xaf17ad190f8dc52>))

vc-responsible-backend("/home/dgutov/examples/emacs-debbugs-58525/tmp3/pro...")
  vc-dir("/home/dgutov/examples/emacs-debbugs-58525/tmp3/pro..." nil)

Not sure how you get to the step of being prompted for the backend.

This should be fixed in Emacs 28.2 released in September. 
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=51800 says Emacs 29 only, 
but it's been backported.

Since you are not seeing the exact error for some reason, it's possible 
that your problem has not been fixed still. But try Emacs 28.2 at least.