Feature: have 'uv export' support --only-deps

[RomainBrault]

Have uv export support --only-deps

This would be useful to support building requirements.txt from uv.lock without including build dependencies.

Example: in a Dockerfile with a custom hatch build the following fails:

COPY pyproject.toml ./
RUN set -ex && \
    ${UV_BIN}/uv export \
        --format="requirements-txt" \
        --all-extras \
        --no-dev

So I must do

COPY pyproject.toml hatch.toml hatch_build.py ./
RUN set -ex && \
    ${UV_BIN}/uv export \
        --format="requirements-txt" \
        --all-extras \
        --no-dev

It would be nice to be able to have

COPY pyproject.toml ./
RUN set -ex && \
    ${UV_BIN}/uv export \
        --format="requirements-txt" \
        --all-extras \
        --no-dev \
        --only-deps

working.

This would also enable doing

uv pip install --require-hashes

without uv complaining about

error: In `--require-hashes` mode, all requirement must have a hash, but none were provided for: file:///src

[RomainBrault]

Related: #6573

If I was unclear, I think it would be nice to convert the uv.lock to a requirements.txt trough uv export with only the dependencies (not the project). I guess I would be really useful if in that case uv would ignore the project's build configuration (otherwise I could just "sed" out the line corresponding to the project in the requirements.txt).

E.g. in my example the project's build use hatch-vcs (with dynamic field + a custom build script) that are not useful to convert the dependencies in uv.lock to requirements.txt.

[charliermarsh]

Do you need --frozen for these commands, so that you don't resolve?

[charliermarsh]

In other words: if you add --frozen to the above examples, do the commands execute without error?

[RomainBrault]

Thanks, this solve the build problem; with --frozen I am able to generate the requirements.txt from the uv.lock.

However I am unable to pip install --require-hashes due to the line -e . in the requirements.txt.

So the final solution is to use --frozen as suggested and to remove the line in a post-processing step.

A flag to avoid this line would still be useful as well as a flag to save the result to a file. (This would avoid post-processing and stream redirections).

I don't mind closing the issue now.

[RomainBrault]

Related: #6995 #7058

[RomainBrault]

I think the feature could be seen another way:

Be able to do uv pip compile uv.lock.