Copier uses questionary 2.1.0 which which looks like it have a open ended dependency on prompt_toolkit. Running a simple questionary in Copier that uses a "when" criteria when answering "no", crashes in 3.0.52. 3.0.51 and earlier is working fine.

Copier template example:

copier.yml

includeFrontend:
    type: bool
    help: Do you want to include a Web frontend
    default: true

includeDocker:
    type: bool
    help: Do you want to include a Container Backend
    default: true

frontendType:
    type: str
    help: What type of frontend
    choices:
        - angular
        - javascript
    when: "{{ includeFrontend }}"

running " copier copy . ." in the folder with the copier.yml, and selecting "no" trigger a crash.

File ".../python3.9/site-packages/questionary/prompts/common.py", line 591, in _fix_unecessary_blank_lines
default_container.get_children()[0].content.get_children()[1].content # type: ignore[attr-defined]
AttributeError: 'VSplit' object has no attribute 'content'