Error in services.mysql with ensureUser and no password

[liammcdermott]

Describe the bug
When using services.mysql.ensureUser without a password, devenv up returns an error:

       … while evaluating the option `processes.mysql-configure.exec':

       … while evaluating definitions from `/nix/store/r5vijlnhrsn07v9456i6z32i4033fj04-source/src/modules/services/mysql.nix':

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: cannot coerce null to a string: null

However, adding password to the ensureUser definition makes the error go away. I see the last commit of src/modules/services/mysql.nix altered the password handling, maybe that commit introduced this bug?

To reproduce
Here's a gist that reproduces the issue.

I believe the issue should be so easy to reproduce that a full backtrace/log isn't necessary. If not, just let me know, and I'll provide one.

Version

devenv 1.0.8 (x86_64-linux)
I am using Nix Flakes on Ubuntu 24.04.

$ nix flake --version
nix (Nix) 2.24.5