This is like #9556, but at the level of all other builds, including the
resolver and installer. Going through PEP 517 to build a package is
slow, so when building a package with the uv build backend, we can call
into the uv build backend directly instead: No temporary virtual env, no
temp venv sync, no python subprocess calls, no uv subprocess calls.
This fast path is gated through preview. Since the uv wheel is not
available at test time, I've manually confirmed the feature by comparing
`uv venv && cargo run pip install . -v --preview --reinstall .` and `uv
venv && cargo run pip install . -v --reinstall .`. When hacking the
preview so that the python uv build backend works without the setting
the direct build also (wheel built with `maturin build --profile
profiling`), we can see the perfomance difference:
```
$ hyperfine --prepare "uv venv" --warmup 3 \
"UV_PREVIEW=1 target/profiling/uv pip install --no-deps --reinstall scripts/packages/built-by-uv --preview" \
"target/profiling/uv pip install --no-deps --reinstall scripts/packages/built-by-uv --find-links target/wheels/"
Benchmark 1: UV_PREVIEW=1 target/profiling/uv pip install --no-deps --reinstall scripts/packages/built-by-uv --preview
Time (mean ± σ): 33.1 ms ± 2.5 ms [User: 25.7 ms, System: 13.0 ms]
Range (min … max): 29.8 ms … 47.3 ms 73 runs
Benchmark 2: target/profiling/uv pip install --no-deps --reinstall scripts/packages/built-by-uv --find-links target/wheels/
Time (mean ± σ): 115.1 ms ± 4.3 ms [User: 54.0 ms, System: 27.0 ms]
Range (min … max): 109.2 ms … 123.8 ms 25 runs
Summary
UV_PREVIEW=1 target/profiling/uv pip install --no-deps --reinstall scripts/packages/built-by-uv --preview ran
3.48 ± 0.29 times faster than target/profiling/uv pip install --no-deps --reinstall scripts/packages/built-by-uv --find-links target/wheels/
```
Do we need a global option to disable the fast path? There is one for
`uv build` because `--force-pep517` moves `uv build` much closer to a
`pip install` from source that a user of a library would experience (See
discussion at #9610), but uv overall doesn't really make guarantees
around the build env of dependencies, so I consider the direct build a
valid option.
Best reviewed commit-by-commit, only the last commit is the actual
implementation, while the preview mode introduction is just a
refactoring touching too many files.
When looking at the build frontend code, I noticed that we always pass
every single field of the shared state to the build dispatch:
```rust
let build_dispatch = BuildDispatch::new(
...
&state.index,
&state.git,
&state.capabilities,
&state.in_flight,
...
);
```
We can abstract this by moving `SharedState` into the build dispatch.
The `BuildDispatch` then has only immutable fields and the
`SharedState`. Since the `SharedState` is all `Arc`s, we can clone it
freely.
When performing a noop sync, we don't need the rayon threadpool, yet we
pay for its initialization:
Be making the initialization lazy, we avoid that cost:
This code runs every time before user code in `uv run`.
This means that before calling rayon, one now needs to call
`LazyLock::force(&RAYON_INITIALIZE);`.
Performance mode (CPU 0 is a perf core):
```
$ taskset -c 0 hyperfine --warmup 5 -N "/home/konsti/projects/uv/uv-main sync" "/home/konsti/projects/uv/target/profiling/uv sync"
Benchmark 1: /home/konsti/projects/uv/uv-main sync
Time (mean ± σ): 4.5 ms ± 0.1 ms [User: 2.7 ms, System: 1.8 ms]
Range (min … max): 4.4 ms … 6.4 ms 640 runs
Warning: Statistical outliers were detected. Consider re-running this benchmark on a quiet system without any interferences from other programs. It might help to use the '--warmup' or '--prepare' options.
Benchmark 2: /home/konsti/projects/uv/target/profiling/uv sync
Time (mean ± σ): 4.4 ms ± 0.1 ms [User: 2.7 ms, System: 1.6 ms]
Range (min … max): 4.3 ms … 5.0 ms 679 runs
Summary
/home/konsti/projects/uv/target/profiling/uv sync ran
1.03 ± 0.04 times faster than /home/konsti/projects/uv/uv-main sync
```
Power saver mode:
```
$ hyperfine --warmup 5 -N "/home/konsti/projects/uv/uv-main sync" "/home/konsti/projects/uv/target/profiling/uv sync"
Benchmark 1: /home/konsti/projects/uv/uv-main sync
Time (mean ± σ): 28.1 ms ± 1.2 ms [User: 15.5 ms, System: 20.3 ms]
Range (min … max): 25.7 ms … 31.9 ms 102 runs
Benchmark 2: /home/konsti/projects/uv/target/profiling/uv sync
Time (mean ± σ): 24.0 ms ± 1.2 ms [User: 13.8 ms, System: 9.9 ms]
Range (min … max): 22.2 ms … 28.2 ms 122 runs
Summary
/home/konsti/projects/uv/target/profiling/uv sync ran
1.17 ± 0.08 times faster than /home/konsti/projects/uv/uv-main sync
```
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## Summary
In uv-globfilter, use the workspace `fs-err` in `dev-dependencies`.
This fixes an unnecessary dev-dependency on `fs-err` 2.x even after the
workspace fs-err was updated to 3.x in
https://github.com/astral-sh/uv/pull/8625.
The `Cargo.lock` file still has `fs-err v2.11.0` after this PR, but it
is via `tracing-durations-export v0.3.0` rather than directly required
by any `uv` crate.
## Test Plan
<!-- How was it tested? -->
```
$ cd crates/uv-globfilter/
$ cargo test
```
## Summary
Update the URL to the "tl" crate since the repository has been
transferred to astral-sh/. This is of no real consequence, except it
keeps triggering Gentoo linter that detects permanently redirected URL.
## Test Plan
`cargo test`
