bug#52347: Shell: error when -m manifest is removed

[Cayetano Santos]

Hi guix,

 Using latest guix, and considering a local manifest.scm file 
 with only

   (specifications->manifest (list "python"))

 Following command works

   guix shell --container -m manifest.scm -- python3

 But

   guix shell --container -- python3

gives an error. However,

   guix shell --container

followed by

   python3

works.

 So, by just removing the ’-m manifest.scm’ flag, I get an error.

Regards,

Cayetano Santos