attribute self.lastModifiedDate missing

[RolfNic]

Context

Several templates in this repository have a reference to the attribute "self.lastModifiedDate", in each of these cases it appears that this property cant be read properly. Ive tested this with the bash-hello and the rust-web-server templates both of which give an error because of the missing attribute. The same holds for the attributes "self.lastModified" and "self.shortRev".

Steps to reproduce

Init one of the flakes in this repository, then build it.

$ nix flake init -t templates#bash-hello
$ nix build
error: attribute 'lastModifiedDate' missing

       at /nix/store/xhqq97pf0v5bd7nk1gwsirr4v621c2il-source/flake.nix:11:40:

           10|       # Generate a user-friendly version number.
           11|       version = builtins.substring 0 8 self.lastModifiedDate;
             |                                        ^
           12|
(use '--show-trace' to show detailed location information)

Possible solutions

1. Make the flakes work as they are.
2. Add a workaround into the templates.

Expected behaviour

Nix builds the flake without any problems.

Additional information

• The nixpkgs flake.nix uses a workaround with a default value.
• This commit message, which fixes the same issue, suggests that something about the path fetcher is broken.

[mayl]

+1 I hit this issue too.