The doc proposes the following Dockerfile to build a project into a Dockerfile while caching intermediate layers (uv version 0.4.0):

# Install uv
FROM python:3.12-slim
COPY --from=ghcr.io/astral-sh/uv:latest /uv /bin/uv

# Change the working directory to the `app` directory
WORKDIR /app

# Copy the lockfile and `pyproject.toml` into the image
ADD uv.lock /app/uv.lock
ADD pyproject.toml /app/pyproject.toml

# Install dependencies
RUN uv sync --frozen --no-install-project

# Copy the project into the image
ADD . /app

# Sync the project
RUN uv sync --frozen

However, when the project is a worskpace, uv sync --frozen --no-install-project won't do anything unless the workspace members are there. As a result, if a workspace contains libs in a libs/ dir, one has to also ADD all libs/*/pyproject.toml files so uv sync --frozen --no-install-project actually installs 3rd party dependencies.
We could easily COPY the whole libs/ dir, but then the cache would be invalidated every time sources change.

Is there a workaround? Or a workspace-specific strategy for building Docker images?