`poetry export --format requirements.txt …` export a commit hash of an installed repository instead of the initial used tag reference.

Poetry is used to build a package that will be installed in a Docker image:

# Build
$ poetry build --format wheel
$ poetry export --format requirements.txt --output constraints.txt --without-hashes

# Export the .whl and constraints.txt file (multi-stage build)

# Install
$ pip install --no-cache-dir ./$APP_NAME*.whl --constraint constraints.txt

As of today, it was working well. But we've added a new package using this (as an example) poetry add git+https://github.com/me/new-package#1.6.0 (new-package = {git = "https://github.com/me/new-package", rev = "1.6.0"} is present in the [tool.poetry.dependencies] of the pyproject.toml) and when we tried to install the generated wheel by Poetry using an exported requirements.txt, we ended up with this error:

The conflict is caused by:
    my-app 1.0.0 depends on new-package 1.6.0 (from git+https://github.com/me/new-package@1.6.0)
    The user requested (constraint) new-package
To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict
ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts

If we take a look at the constraints.txt file, we can see that line: new-package @ git+https://github.com/me/new-package@c3e22d63f50256f588bd1438eedcd761a1507a43 ; python_version >= "3.11" and python_version < "4.0", which doesn't match the initial git+https://github.com/me/new-package@1.6.0.

Workarounds

If we replace this line by new-package @ git+https://github.com/me/new-package@1.6.0 the problem disappear.

Reproduce the issue with the shown poetry build and poetry export commands, using the git dependency in pyproject.toml. Inspect the generated constraints.txt and compare its commit-hash reference with the original 1.6.0 tag; done means the exported requirement preserves the usable reference and pip can install the wheel with the constraints file.