Sub-theme regions created with drush generate theme don't match

[gitressa]

Describe the bug

Drush supports creating a sub-theme, which is great (see Generating a new sub-theme using Drush).

But the regions are not copied over from the base theme into the sub-theme *.info.yml file, so they are different, and block placements are not inherited.

To make it work as expected, you need to manually copy the regions from base- to sub-theme, before installing the sub-theme.

To Reproduce
Create a sub-theme with drush generate theme, set olivero as base theme.

Expected behavior
That the regions from the base theme Olivero would be present in the new sub-theme.

Actual behavior
The standard regions were present in the *.info.yml file, as when creating a stand alone theme.

Workaround
Manually copy the regions from the base theme to the sub-theme, before installing the sub-theme.

Suggested solution
Either update the code to make it copy over the regions, or add a note during step "#3 Base theme", that you need to copy over the regions manually.

System Configuration

Q	A
Drush version?	12.x
Drupal version?	10.x
PHP version	8.x
OS?	Linux

Additional information
Add any other context about the problem here.

[weitzman]

The theme generator (and most other generators) comes from https://github.com/Chi-teck/drupal-code-generator/. Please post issues/PRs there.