This PR migrates uv's use of `chrono` to `jiff`.
I did most of this work a while back as one of my tests to ensure Jiff
could actually be used in a real world project. I decided to revive
this because I noticed that `reqwest-retry` dropped its Chrono
dependency,
which is I believe the only other thing requiring Chrono in uv.
(Although, we use a fork of `reqwest-middleware` at present, and that
hasn't been updated to latest upstream yet. I wasn't quite sure of the
process we have for that.)
In course of doing this, I actually made two changes to uv:
First is that the lock file now writes an RFC 3339 timestamp for
`exclude-newer`. Previously, we were using Chrono's `Display`
implementation for this which is a non-standard but "human readable"
format. I think the right thing to do here is an RFC 3339 timestamp.
Second is that, in addition to an RFC 3339 timestamp, `--exclude-newer`
used to accept a "UTC date." But this PR changes it to a "local date."
That is, a date in the user's system configured time zone. I think
this makes more sense than a UTC date, but one alternative is to drop
support for a date and just rely on an RFC 3339 timestamp. The main
motivation here is that automatically assuming UTC is often somewhat
confusing, since just writing an unqualified date like `2024-08-19` is
often assumed to be interpreted relative to the writer's "local" time.
## Summary
The strategy here is: if the user provides supported environments, we
use those as the initial forks when resolving. As a result, we never add
or explore branches that are disjoint with the supported environments.
(If the supported environments change, we ignore the lockfile entirely,
so we don't have to worry about any interactions between supported
environments and the preference forks.)
Closes https://github.com/astral-sh/uv/issues/6184.
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.
## Summary
After referring to https://github.com/astral-sh/uv/pull/5637 and doing
additional testing.
The default value in a stable state seems more reasonable to be
``only-system``. ``managed`` in preview.
```
cpython-3.11.9-windows-x86_64-none C:\Users\name\AppData\Local\Programs\Python\Python311\python.exe
cpython-3.10.14-windows-x86_64-none C:\Users\name\AppData\Roaming\uv\data\python\cpython-3.10.14-windows-x86_64-none\install\python.exe
cpython-3.10.11-windows-x86_64-none C:\Users\name\AppData\Local\Programs\Python\Python310\python.exe
cpython-3.9.19-windows-x86_64-none C:\Users\name\AppData\Roaming\uv\data\python\cpython-3.9.19-windows-x86_64-none\python.exe
```
test on uv 0.2.33 (build from
257007ccaf)
### Stable version
``uv venv -p 3.10`` is ``3.10.11`` (System Python)
``uv venv -p 3.9`` is ``No interpreter found``(3.9.19 for managed
Python)
``uv venv -p 3.9 --python-preference only-system`` is ``No interpreter
found``(fail)
``uv venv -p 3.9 --python-preference only-managed`` is
``3.9.19``(success)
Do not use managed Python, only use the system Python, so it can be
determined as ``only-system``.
### Preview mode
**Note:** ``3.10.14`` is managed python, ``3.10.11`` is system python.
``uv venv -p 3.11 --preview`` is ``3.11.9`` (System Python)
``uv venv -p 3.10 --preview`` is ``3.10.14``
``uv venv -p 3.10 --preview --python-preference only-managed`` is
``3.10.14``
``uv venv -p 3.10 --preview --python-preference managed`` is ``3.10.14``
``uv venv -p 3.10 --preview --python-preference system`` is ``3.10.11``
``venv -p 3.10 --preview --python-preference only-system`` is
``3.10.11``
Prioritize the managed Python and then select the system Python, so it
can be determined as ``managed``.
-----
fixed#5754
## Test Plan
Run website in local.
