The loose consensus is that "fetch" doesn't have much meaning and that a
boolean flag makes more sense from the command line.
1. Adds `--allow-python-downloads` (hidden, default) and
`--no-python-downloads` to the CLI to quickly enable or disable
downloads
2. Deprecates `--python-fetch` in favor of the options from (1)
3. Removes `python-fetch` in favor of a `python-downloads` setting
5. Adds a `never` variant to the enum, allowing even explicit installs
to be disabled via the configuration file
## Test plan
I tested this with various `pyproject.toml`-level settings and `uv venv
--preview --python 3.12.2` and `uv python install 3.12.2` with and
without the new CLI flags.
This already rejects `pyproject.toml`... but because the schema
validation is relaxed (we allow unknown fields, and all fields are
optional), a `pyproject.toml` doesn't get properly rejected here.
This PR makes the schema stricter, but in a safe way (by adding the
other `tool.uv` fields, like `workspace`, as any).
Closes#5832.
Whew this is a lot.
The user-facing changes are:
- `uv toolchain` to `uv python` e.g. `uv python find`, `uv python
install`, ...
- `UV_TOOLCHAIN_DIR` to` UV_PYTHON_INSTALL_DIR`
- `<UV_STATE_DIR>/toolchains` to `<UV_STATE_DIR>/python` (with
[automatic
migration](https://github.com/astral-sh/uv/pull/4735/files#r1663029330))
- User-facing messages no longer refer to toolchains, instead using
"Python", "Python versions" or "Python installations"
The internal changes are:
- `uv-toolchain` crate to `uv-python`
- `Toolchain` no longer referenced in type names
- Dropped unused `SystemPython` type (previously replaced)
- Clarified the type names for "managed Python installations"
- (more little things)
Adds a `toolchain-fetch` option alongside `toolchain-preference` with
`automatic` (default) and `manual` values allowing automatic toolchain
fetches to be disabled (replaces
https://github.com/astral-sh/uv/pull/4425). When `manual`, toolchains
must be installed with `uv toolchain install`.
Note this was previously implemented with `if-necessary`, `always`,
`never` variants but the interaction between this and
`toolchain-preference` was too confusing. By reducing to a binary
option, things should be clearer. The `if-necessary` behavior moved to
`toolchain-preference=installed`. See
https://github.com/astral-sh/uv/pull/4601#discussion_r1657839633 and
https://github.com/astral-sh/uv/pull/4601#discussion_r1658658755
Exposes the option added in #4416. Adds `--toolchain-preference` and
`tool.uv.toolchain-preference` to configure if system or managed
toolchains are preferred. Users can opt-out of managed toolchains or
system toolchains entirely as well.
## Summary
In a workspace, we now read configuration from the workspace root.
Previously, we read configuration from the first `pyproject.toml` or
`uv.toml` file in path -- but in a workspace, that would often be the
_project_ rather than the workspace configuration.
We need to read configuration from the workspace root, rather than its
members, because we lock the workspace globally, so all configuration
applies to the workspace globally.
As part of this change, the `uv-workspace` crate has been renamed to
`uv-settings` and its purpose has been narrowed significantly (it no
longer discovers a workspace; instead, it just reads the settings from a
directory).
If a user has a `uv.toml` in their directory or in a parent directory
but is _not_ in a workspace, we will still respect that use-case as
before.
Closes#4249.
Charlie Marsh
Zanie Blue