Hi! While migrating an existing Python project to uv, I encountered a situation where a command similar to cargo update --precise would be quite useful. Essentially, I would like to have the option to tell uv to set a package version (usually of a transitive dependency, one that is not specified in dependencies) in a lockfile to a specific version (that is semver compatible with the other dependencies).

I have the following use-case (related to #7018): I'm porting an existing Python project using a requirements.txt lockfile to uv. Let's say that I have a root dependency a that depends on a transitive dependency b>2.1, and the latest published version of b is 2.3. However, in my existing Python environment, I'm using b==2.2, and I want to continue doing that. In theory, according to semver, 2.3 is compatible with 2.2, but theory is not always practice (especially in the world of Python package management :) ).

If I want to move to uv, I'll generate a new project, set dependencies = ["a==xyz"] and generate a lockfile. However, uv will forcefully set the version of b to 2.3, the newest compatible version. I haven't found any way to tell uv to set a specific version of the transitive dependency (aside from manually modifying the lockfile, but that's really not a good solution).

Workaround

What I found to work is to do uv add b==2.2, which will update the lockfile, and then manually delete "b==2.2" from the dependencies array. This seems to work fine, but it would be nice if uv allowed me to do this in a more straightforward way, e.g. with something like uv lock update b=2.2.

Related issue

A bit similar to #6794, but I'm looking for a way to set the version of a specific package to a specific version, not just update everything.