Geoffrey Thomas df44199ceb Add an exception handler on Windows (#14582)
We've seen a few cases of uv.exe exiting with an exception code as its
exit status and no user-visible output (#14563 in the field, and #13812
in CI). It seems that recent versions of Windows no longer show dialog
boxes on access violations (what UNIX calls segfaults) or similar
errors. Something is probably sent to Windows Error Reporting, and we
can maybe sign up to get the crashes from Microsoft, but the user
experience of seeing uv exit with no output is poor, both for end users
and during development. While it's possible to opt out of this behavior
or set up a debugger, this isn't the default configuration. (See
https://superuser.com/q/1246626 for some pointers.)

In order to get some output on a crash, we need to install our own
default handler for unhandled exceptions (or call all our code inside a
Structured Exception Handling __try/__catch block, which is complicated
on Rust). This is the moral equivalent of a segfault handler on Windows;
the kernel creates a new stack frame and passes arguments to it with
some processor state.

This commit adds a relatively simple exception handler that leans on
Rust's own backtrace implementation and also displays some minimal
information from the exception itself. This should be enough info to
communicate that something went wrong and let us collect enough
information to attempt to debug. There are also a handful of (non-Rust)
open-source libraries for this like Breakpad and Crashpad (both from
Google) and crashrpt.

The approach here, of using SetUnhandledExceptionFilter, seems to be the
standard one taken by other such libraries. Crashpad also seems to try
to use a newer mechanism for an out-of-tree DLL to report the crash:
https://issues.chromium.org/issues/42310037
If we have serious problems with memory corruption, it might be worth
adopting some third-party library that has already implemented this
approach. (In general, the docs of other crash reporting libraries are
worth skimming to understand how these things ought to work.)

Co-authored-by: samypr100 <3933065+samypr100@users.noreply.github.com>
2025-07-14 10:42:35 -04:00
2024-08-20 16:42:57 +00:00
2025-06-20 14:20:01 -04:00
2025-01-04 18:31:36 +00:00
2025-01-04 18:31:36 +00:00
2025-07-09 12:15:41 -05:00
2025-05-27 16:11:54 +00:00
2025-06-17 17:28:23 +00:00
2025-06-16 10:05:56 -04:00

uv

uv image image image Actions status Discord

An extremely fast Python package and project manager, written in Rust.

Shows a bar chart with benchmark results.

Installing Trio's dependencies with a warm cache.

Highlights

uv is backed by Astral, the creators of Ruff.

Installation

Install uv with our standalone installers:

# On macOS and Linux.
curl -LsSf https://astral.sh/uv/install.sh | sh
# On Windows.
powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"

Or, from PyPI:

# With pip.
pip install uv
# Or pipx.
pipx install uv

If installed via the standalone installer, uv can update itself to the latest version:

uv self update

See the installation documentation for details and alternative installation methods.

Documentation

uv's documentation is available at docs.astral.sh/uv.

Additionally, the command line reference documentation can be viewed with uv help.

Features

Projects

uv manages project dependencies and environments, with support for lockfiles, workspaces, and more, similar to rye or poetry:

$ uv init example
Initialized project `example` at `/home/user/example`

$ cd example

$ uv add ruff
Creating virtual environment at: .venv
Resolved 2 packages in 170ms
   Built example @ file:///home/user/example
Prepared 2 packages in 627ms
Installed 2 packages in 1ms
 + example==0.1.0 (from file:///home/user/example)
 + ruff==0.5.0

$ uv run ruff check
All checks passed!

$ uv lock
Resolved 2 packages in 0.33ms

$ uv sync
Resolved 2 packages in 0.70ms
Audited 1 package in 0.02ms

See the project documentation to get started.

uv also supports building and publishing projects, even if they're not managed with uv. See the publish guide to learn more.

Scripts

uv manages dependencies and environments for single-file scripts.

Create a new script and add inline metadata declaring its dependencies:

$ echo 'import requests; print(requests.get("https://astral.sh"))' > example.py

$ uv add --script example.py requests
Updated `example.py`

Then, run the script in an isolated virtual environment:

$ uv run example.py
Reading inline script metadata from: example.py
Installed 5 packages in 12ms
<Response [200]>

See the scripts documentation to get started.

Tools

uv executes and installs command-line tools provided by Python packages, similar to pipx.

Run a tool in an ephemeral environment using uvx (an alias for uv tool run):

$ uvx pycowsay 'hello world!'
Resolved 1 package in 167ms
Installed 1 package in 9ms
 + pycowsay==0.0.0.2
  """

  ------------
< hello world! >
  ------------
   \   ^__^
    \  (oo)\_______
       (__)\       )\/\
           ||----w |
           ||     ||

Install a tool with uv tool install:

$ uv tool install ruff
Resolved 1 package in 6ms
Installed 1 package in 2ms
 + ruff==0.5.0
Installed 1 executable: ruff

$ ruff --version
ruff 0.5.0

See the tools documentation to get started.

Python versions

uv installs Python and allows quickly switching between versions.

Install multiple Python versions:

$ uv python install 3.10 3.11 3.12
Searching for Python versions matching: Python 3.10
Searching for Python versions matching: Python 3.11
Searching for Python versions matching: Python 3.12
Installed 3 versions in 3.42s
 + cpython-3.10.14-macos-aarch64-none
 + cpython-3.11.9-macos-aarch64-none
 + cpython-3.12.4-macos-aarch64-none

Download Python versions as needed:

$ uv venv --python 3.12.0
Using Python 3.12.0
Creating virtual environment at: .venv
Activate with: source .venv/bin/activate

$ uv run --python pypy@3.8 -- python --version
Python 3.8.16 (a9dbdca6fc3286b0addd2240f11d97d8e8de187a, Dec 29 2022, 11:45:30)
[PyPy 7.3.11 with GCC Apple LLVM 13.1.6 (clang-1316.0.21.2.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>>

Use a specific Python version in the current directory:

$ uv python pin 3.11
Pinned `.python-version` to `3.11`

See the Python installation documentation to get started.

The pip interface

uv provides a drop-in replacement for common pip, pip-tools, and virtualenv commands.

uv extends their interfaces with advanced features, such as dependency version overrides, platform-independent resolutions, reproducible resolutions, alternative resolution strategies, and more.

Migrate to uv without changing your existing workflows — and experience a 10-100x speedup — with the uv pip interface.

Compile requirements into a platform-independent requirements file:

$ uv pip compile docs/requirements.in \
   --universal \
   --output-file docs/requirements.txt
Resolved 43 packages in 12ms

Create a virtual environment:

$ uv venv
Using Python 3.12.3
Creating virtual environment at: .venv
Activate with: source .venv/bin/activate

Install the locked requirements:

$ uv pip sync docs/requirements.txt
Resolved 43 packages in 11ms
Installed 43 packages in 208ms
 + babel==2.15.0
 + black==24.4.2
 + certifi==2024.7.4
 ...

See the pip interface documentation to get started.

Platform support

See uv's platform support document.

Versioning policy

See uv's versioning policy document.

Contributing

We are passionate about supporting contributors of all levels of experience and would love to see you get involved in the project. See the contributing guide to get started.

FAQ

How do you pronounce uv?

It's pronounced as "you - vee" (/juː viː/)

How should I stylize uv?

Just "uv", please. See the style guide for details.

Acknowledgements

uv's dependency resolver uses PubGrub under the hood. We're grateful to the PubGrub maintainers, especially Jacob Finkelman, for their support.

uv's Git implementation is based on Cargo.

Some of uv's optimizations are inspired by the great work we've seen in pnpm, Orogene, and Bun. We've also learned a lot from Nathaniel J. Smith's Posy and adapted its trampoline for Windows support.

License

uv is licensed under either of

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in uv by you, as defined in the Apache-2.0 license, shall be dually licensed as above, without any additional terms or conditions.

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