## Summary
This PR consolidates the concurrency limits used throughout `uv` and
exposes two limits, `UV_CONCURRENT_DOWNLOADS` and
`UV_CONCURRENT_BUILDS`, as environment variables.
Currently, `uv` has a number of concurrent streams that it buffers using
relatively arbitrary limits for backpressure. However, many of these
limits are conflated. We run a relatively small number of tasks overall
and should start most things as soon as possible. What we really want to
limit are three separate operations:
- File I/O. This is managed by tokio's blocking pool and we should not
really have to worry about it.
- Network I/O.
- Python build processes.
Because the current limits span a broad range of tasks, it's possible
that a limit meant for network I/O is occupied by tasks performing
builds, reading from the file system, or even waiting on a `OnceMap`. We
also don't limit build processes that end up being required to perform a
download. While this may not pose a performance problem because our
limits are relatively high, it does mean that the limits do not do what
we want, making it tricky to expose them to users
(https://github.com/astral-sh/uv/issues/1205,
https://github.com/astral-sh/uv/issues/3311).
After this change, the limits on network I/O and build processes are
centralized and managed by semaphores. All other tasks are unbuffered
(note that these tasks are still bounded, so backpressure should not be
a problem).
## Summary
We already _don't_ discover a `pyproject.toml` in `~/.config/uv` -- it
must be `uv.toml`. This PR makes the same change for `--config-file` --
it _has_ to be a `uv.toml`.
I think this is reasonable and more consistent, though I'm not sure. A
`pyproject.toml` "means" something -- it defines a project itself, in
which case we should be using project configuration. But creating a
`pyproject.toml` outside the project and passing it via `--config-file`
seems like an anti-pattern.
## Summary
This PR follows Cargo's strategy for merging configuration, albeit in a
more limited way (we don't support as many configuration locations).
Specifically, we merge the user configuration with the workspace
configuration if both are present. The workspace configuration has
priority, such that we take values from the workspace configuration and
ignore those in the user configuration if both are specified for a given
setting -- with the exception of arrays and maps, which are
concatenated.
For now, if a user provides a configuration file with `--config-file`,
we _don't_ merge in the user settings.
See:
https://doc.rust-lang.org/cargo/reference/config.html#hierarchical-structure.
Closes#3420.
Moves all of `uv-toolchain` into `uv-interpreter`. We may split these
out in the future, but the refactoring I want to do for interpreter
discovery is easier if I don't have to deal with entanglement. Includes
some restructuring of `uv-interpreter`.
Part of #2386
## Summary
The approach taken here is to model `--target` as an install scheme in
which all the directories are just subdirectories of the `--target`.
From there, everything else... just works? Like, upgrade, uninstalls,
editables, etc. all "just work".
Closes#1517.
## Summary
The function `find_in_directory` joins `uv.toml`. The initial join in
`user` is redundant.
Also a small comment fix.
## Test Plan
Not really sure how to test this. Please suggest if any tests need to be
added.
Adds hidden `--preview` / `--no-preview` flags with `UV_PREVIEW`
environment variable support. Copies the `PreviewMode` type from Ruff.
Does a little bit of extra work to port `uv run` to the new settings
model.
Note we allow `uv run` invocations without preview and only use its
presence to toggle an experimental warning.
## Test plan
```
❯ cargo run -q -- run --no-workspace -- python --version
warning: `uv run` is experimental and may change without warning.
Python 3.12.2
❯ cargo run -q -- run --no-workspace --preview -- python --version
Python 3.12.2
❯ UV_PREVIEW=1 cargo run -q -- run --no-workspace -- python --version
Python 3.12.2
```
## Summary
Enables `uv` to read configuration from (e.g.)
`/Users/crmarsh/.config/uv/uv.toml` on macOS and Linux, and
`C:\Users\Charlie\AppData\Roaming\uv\uv.toml` on Windows.
This differs slightly from Ruff, which uses the `Application Support`
directory on macOS. But I've deviated here. based on the preferences
expressed in https://github.com/astral-sh/ruff/issues/10739.
## Summary
This PR adds the structs and logic necessary to respect settings from
the workspace. It's a ton of code, but it's mostly mechanical. And,
believe it or not, I pulled out a few refactors in advance to trim down
the code and complexity.
The highlights are:
- All CLI arguments are now `Option`, so that we can detect whether they
were provided (i.e., we can't let Clap fill in the defaults).
- We now have a `*Settings` struct for each command, which merges the
CLI and workspace options (e.g., `PipCompileSettings`).
I've only implemented `PipCompileSettings` for now. If approved, I'll
implement the others prior to merging, but it's very mechanical and I
both didn't want to do the conversion prior to receiving feedback _and_
realized it would make the PR harder to review.
## Summary
This PR adds basic struct definitions along with a "workspace" concept
for discovering settings. (The "workspace" terminology is used to match
Ruff; I did not invent it.)
A few notes:
- We discover any `pyproject.toml` or `uv.toml` file in any parent
directory of the current working directory. (We could adjust this to
look at the directories of the input files.)
- We don't actually do anything with the configuration yet; but those
PRs are large and I want this to be reviewed in isolation.
