`uv sync` does not respect `VIRTUAL_ENV`

[johnthagen]

Oversight in

• Port from Poetry to uv #255

uv sync does not respect VIRTUAL_ENV like Poetry did

• uv add/uv sync/... do not respect the active virtualenv, should they? astral-sh/uv#6612 (comment)
• Support custom venv locations for uv sync astral-sh/uv#5229

#14 [python_builder 6/9] RUN uv sync --locked --no-default-groups --no-install-project
#14 0.113 warning: `VIRTUAL_ENV=/opt/venv` does not match the project environment path `.venv` and will be ignored; use `--active` to target the active environment instead

In the case of python-blueprint it ends up "working" because

RUN uv build && \
    pip install dist/*.whl

will install the (unlocked) dependencies for the project.

The recommended alternative from uv is UV_PROJECT_ENVIRONMENT

• Allow customizing the project environment path with UV_PROJECT_ENVIRONMENT astral-sh/uv#6834
• https://docs.astral.sh/uv/concepts/projects/config/#project-environment-path

Or the default .venv could be hard-coded.

[johnthagen]

A good resource

• https://hynek.me/articles/docker-uv/