Support default value in template?

[kamontat]

Description

I would love of we could define default value when template variable is not available.

What problem it is solving?

My use-case is I would like to have share config like

commit-msg:
  commands:
    check:msg:
      run: {check:msg:cmd?pnpm} check:msg --edit {1}

then on project config, we could do like

## Use default pnpm command
extends:
  - ../shared/lefthook.yaml
---

## Override command to npm instead
extends:
  - ../shared/lefthook.yaml
templates:
  "check:msg:cmd": npm

[mrexox]

Hey! But it's the same thing as having the explicitly defined templates in the config file.

# ../shared/lefthook.yaml

template:
  "check:msg:cmd": pnpm

commit-msg:
  commands:
    check:msg:
      run: {check:msg:cmd} check:msg --edit {1}

Although this can't be overwritten in the main config, because extends get merged and overwrite settings in the main config. The only workaround is to have a lefthook-local.yml with the templates setting.

I'd like to stick with explicit templates because you may have many templates in the config and it's always good to know which exactly get used in the file.