Unify cargo features (#9267)
When building only a single crate in the workspace to run its tests, we
often recompile a lot of other, unrelated crates. Whenever cargo has a
different set of crate features, it needs to recompile. By moving some
features (non-exhaustive for now) to the workspace level, we always
activate them an avoid recompiling.
The cargo docs mismatch the behavior of cargo around default-deps, so I
filed that upstream and left most `default-features` mismatches:
https://github.com/rust-lang/cargo/issues/14841.
Reference script:
```python
import tomllib
from collections import defaultdict
from pathlib import Path
uv = Path("/home/konsti/projects/uv")
skip_list = ["uv-trampoline", "uv-dev", "uv-performance-flate2-backend", "uv-performance-memory-allocator"]
root_feature_map = defaultdict(set)
root_default_features = defaultdict(bool)
cargo_toml = tomllib.loads(uv.joinpath("Cargo.toml").read_text())
for dep, declaration in cargo_toml["workspace"]["dependencies"].items():
root_default_features[dep] = root_default_features[dep] or declaration.get("default-features", True)
root_feature_map[dep].update(declaration.get("features", []))
feature_map = defaultdict(set)
default_features = defaultdict(bool)
for crate in uv.joinpath("crates").iterdir():
if crate.name in skip_list:
continue
if not crate.joinpath("Cargo.toml").is_file():
continue
cargo_toml = tomllib.loads(crate.joinpath("Cargo.toml").read_text())
for dep, declaration in cargo_toml.get("dependencies", {}).items():
# If any item uses default features, they are used everywhere
default_features[dep] = default_features[dep] or declaration.get("default-features", True)
feature_map[dep].update(declaration.get("features", []))
for dep, features in sorted(feature_map.items()):
features = features - root_feature_map.get(dep, set())
if not features and default_features[dep] == root_default_features[dep]:
continue
print(dep, default_features[dep], sorted(features))
```
