Python tools run with `python -m <tool>` will use this `python` as their default python, including pip, virtualenv and the built-in venv. Calling Python tools this way is common, the [pip docs](https://pip.pypa.io/en/stable/user_guide/) use `python -m pip` exclusively, the built-in venv can only be called this way and certain project layouts require `python -m pytest` over `pytest`. This python interpreter takes precedence over the currently active (v)env.
These tools are all written in python and read `sys.executable`. To emulate this, we're setting `UV_DEFAULT_PYTHON` in the python module-launcher shim and read it in the default python discovery, prioritizing it over the active venv. User can also set `UV_DEFAULT_PYTHON` for their own purposes.
The test covers only half of the feature since we don't build the python package before running the tests.
Fixes#2058Fixes#2222
The architecture of uv does not necessarily match that of the python
interpreter (#2326). In cross compiling/testing scenarios the operating
system can also mismatch. To solve this, we move arch and os detection
to python, vendoring the relevant pypa/packaging code, preventing
mismatches between what the python interpreter was compiled for and what
uv was compiled for.
To make the scripts more manageable, they are now a directory in a
tempdir and we run them with `python -m` . I've simplified the
pypa/packaging code since we're still building the tags in rust. A
`Platform` is now instantiated by querying the python interpreter for
its platform. The pypa/packaging files are copied verbatim for easier
updates except a `lru_cache()` python 3.7 backport.
Error handling is done by a `"result": "success|error"` field that allow
passing error details to rust:
```console
$ uv venv --no-cache
× Can't use Python at `/home/konsti/projects/uv/.venv/bin/python3`
╰─▶ Unknown operation system `linux`
```
I've used the [maturin sysconfig
collection](855f6d2cb1/sysconfig)
as reference. I'm unsure how to test these changes across the wide
variety of platforms.
Fixes#2326
## Summary
Small follow up to https://github.com/astral-sh/uv/pull/2362 to check if
`SSL_CERT_FILE` is set to enable `--native-tls` functionality. This
maintains backwards compatibility with `0.1.17` and below users
leveraging only `SSL_CERT_FILE`.
Closes https://github.com/astral-sh/uv/issues/2400
## Test Plan
<!-- How was it tested? -->
Assuming `SSL_CERT_FILE` is already working via `--native-tls`, this is
simply a shortcut to enable `--native-tls` functionality implicitly
while still being able to let `rustls-native-certs` handle the loading
of `SSL_CERT_FILE` instead of ourselves.
Edit: Manually tested by setting up own self-signed CA certificate
bundle and set `SSL_CERT_FILE` to this and confirmed the loading happens
without having to specify `--native-tls`.
## Summary
Per [PEP 508](https://peps.python.org/pep-0508/), `python_version` is
just major and minor:

Right now, we're using the provided version directly, so if it's, e.g.,
`-p 3.11.8`, we'll inject the wrong marker. This was causing `pandas` to
omit `numpy` when `-p 3.11.8` was provided, since its markers look like:
```
Requires-Dist: numpy<2,>=1.22.4; python_version < "3.11"
Requires-Dist: numpy<2,>=1.23.2; python_version == "3.11"
Requires-Dist: numpy<2,>=1.26.0; python_version >= "3.12"
```
Closes https://github.com/astral-sh/uv/issues/2392.
## Summary
This PR ensures that we expand environment variables _before_ sniffing
for the URL scheme (e.g., `file://` vs. `https://` vs. something else).
Closes https://github.com/astral-sh/uv/issues/2375.
## Summary
This is a more robust fix for
https://github.com/astral-sh/uv/issues/2300.
The basic issue is:
- When we resolve, we attempt to pre-fetch the distribution metadata for
candidate packages.
- It's possible that the resolution completes _without_ those pre-fetch
responses. (In the linked issue, this was mainly because we were running
with `--no-deps`, but the pre-fetch was causing us to attempt to build a
package to get its dependencies. The resolution would then finish before
the build completed.)
- In that case, the `Index` will be marked as "waiting" for that
response -- but it'll never come through.
- If there's a subsequent call to the `Index`, to see if we should fetch
or are waiting for that response, we'll end up waiting for it forever,
since it _looks_ like it's in-flight (but isn't). (In the linked issue,
we had to build the source distribution for the install phase of `pip
install`, but `setuptools` was in this bad state from the _resolve_
phase.)
This PR modifies the resolver to ensure that we flush the stream of
requests before returning. Specifically, we now `join` rather than
`select` between the resolution and request-handling futures.
This _could_ be wasteful, since we don't _need_ those requests, but it
at least ensures that every `.wait` is followed by ` .done`. In
practice, I expect this not to have any significant effect on
performance, since we end up using the pre-fetched distributions almost
every time.
## Test Plan
I ran through the test plan from
https://github.com/astral-sh/uv/pull/2373, but ran the build 10 times
and ensured it never crashed. (I reverted
https://github.com/astral-sh/uv/pull/2373, since that _also_ fixes the
issue in the proximate case, by never fetching `setuptools` during the
resolve phase.)
I also added logging to verify that requests are being handled _after_
the resolution completes, as expected.
I also introduced an arbitrary error in `fetch` to ensure that the error
was immediately propagated.
## What
Adds a `--dry-run` flag that ejects out of the installation process
early (but after resolution) and displays only what *would have*
installed
## Closes
Closes#1244
## Out of Scope
I think it may be nice to include a `dry-run` flag for `uninstall` even
though `pip` doesn't implement this... thinking `Would uninstall X
packages: ...`
---------
Co-authored-by: Zanie Blue <contact@zanie.dev>
## Summary
Follow-up for
395be442fc
adds `Requires` field to pip show output.
I've aimed to make it behave exactly the same as `pip` does for now, but
there seem to be subtle issues that may require some discussion going
forward:
- Should `uv pip show` support extras? `pip` has an open issue for it,
but currently does not support https://github.com/pypa/pip/issues/4824.
- Relatedly, `Requred-by` field (not implemented in this PR) in `pip
show` currently doesn't take the extras into account transparently, i.e.
when `PySocks` has been installed as an extra for `requests[socks]`,
`pip show PySocks` doesn't have `requests` or `requests[socks]` under
`Requred-by` field. Should `uv pip show` for now just replicate `pip`'s
behavior for now for simplicity and parity or try to cover the extras
for completeness?
## Test Plan
Added a couple of tests:
1. `requests==2.31.0` has four dependencies that would be ordered
differently unless sorted. Additionally, it has two dependencies that
are optionally included for extras.
2. `pandas==2.1.3` depends on different versions of `numpy` depending on
the python version used.
## Summary
It turns out that on macOS, reading the native certificates can add
hundreds of milliseconds to client initialization. This PR makes
`--native-tls` a command-line flag, to toggle (at runtime) the choice of
the `webpki` roots or the native system roots.
You can't accomplish this kind of configuration with the `reqwest`
builder API, so instead, I pulled out the heart of that logic from the
crate
(e319263851/src/async_impl/client.rs (L498)),
and modified it to allow toggling a choice of root.
Note that there's an open PR for this in reqwest
(https://github.com/seanmonstar/reqwest/pull/1848), along with an issue
(https://github.com/seanmonstar/reqwest/issues/1843), which I may ping,
but it's been around for a while and I believe reqwest is focused on its
next major release.
Closes https://github.com/astral-sh/uv/issues/2346.
## Summary
When running under `--no-deps`, we don't need to pre-fetch, because
pre-fetching fetches the _distribution_ metadata. But with `--no-deps`,
we only need the package metadata for the top-level requirements. We
never need distribution metadata.
Incidentally, this will fix https://github.com/astral-sh/uv/issues/2300.
## Test Plan
- `cargo test`
- `./target/debug/uv pip install --verbose --no-cache-dir --no-deps
--reinstall ddtrace==2.6.2 debugpy==1.8.1 ecdsa==0.18.0
editorconfig==0.12.4 --verbose` in a Python 3.10 Docker contain
repeatedly.
## Summary
This is analogous to #669, but for cases in which the package name is a
filesystem path. In such cases, we'll fail when parsing the _package
name_, since it doesn't start with a valid character, as opposed to
failing when we go to parse the remaining version specifier.
Inspired by https://github.com/astral-sh/uv/issues/2356.
## Summary
Add a new env variable `UV_SYSTEM` as alias for the cli argument
`--system`.
Use cases:
- No need to specify on each uv call inside the docker container the
`--system` flag
- It allows installing and configuring uv in a base container and in the
child containers nobody needs to know if you need the `--system` cli
flag
- The Home Assistant development env can be set up via devcontainer or a
venv. Both use some common scripts. Instead of adding duplicate or
special code to identify the dev container to set the `--system` flag,
it would be nicer to set it via an env variable.
I'm unfamiliar with Rust and tried to add the support by looking at the
code.
## Test Plan
I did test it manually
`UV_SYSTEM_PYTHON=true uv pip install requests`
## Summary
It turns out that when we iterate over the incompatibilities of a
package, PubGrub will _also_ show us the inverse dependencies. I suspect
this was rare, because we have a version check at the bottom... So, this
specifically required that you had some dependency that didn't end up
appearing in the output resolution, but that matched the version
constraints of the package you care about.
In this case, `langchain-community` depends on `langchain-core`. So we
were seeing an incompatibility like:
```rust
FromDependencyOf(Package(PackageName("langchain-community"), None, None), Range { segments: [(Included("0.0.10"), Included("0.0.10")), (Included("0.0.11"), Included("0.0.11"))] }, Package(PackageName("langchain-core"), None, None), Range { segments: [(Included("0.1.8"), Excluded("0.2"))] })
```
Where we were iterating over `langchain-core`, and looking for version
`0.0.11`... which happens to match `langchain-community`.
(`langchain-community was omitted from the resolution; hence, it didn't
exist in the map.)
Closes https://github.com/astral-sh/uv/issues/2358.
Behind error messages, the debug log is the second most important
resource to finding out what and why went wrong when there was a problem
with uv. It is important to see which paths it has found and how the
decisions in the resolver were made. I'm trying to improve the
experience interacting with the debug log.
The hierarchical layer is verbose and hard to follow, so it's moved to
the `-vv` extra verbose setting, while `-v` works like
`RUST_LOG=uv=debug`.
For installing jupyter with a warm cache:
* Default:
https://gist.github.com/konstin/4de6e466127311c5a5fc2f99c56a8e11
* `-v`: https://gist.github.com/konstin/e7bafe0ec7d07e47ba98a3865ae2ef3e
* `-vv`:
https://gist.github.com/konstin/3ee1aaff37f91cceb6275dd5525f180e
Ideally, we would have `-v`, `-vv` and `-vvv`, but we're lacking the the
`info!` layer for `-v`, so there's only two layers for now.
The `tracing_subcriber` formatter always print the current span, so i
replaced it with a custom formatter.

Best read commit-by-commit.
## Summary
We now initialize an HTTP client in advance for remote requirements
files. It turns out this adds a significant overhead, even for
operations like auditing the environment (at least on macOS).
This PR makes initialization lazy. After a lot of evaluation, I took the
easiest route, which is: we just pass in `Connectivity`, and then use
the default HTTP client. So we won't respect netrc files and anything
else that we get from our registry client. If we want to keep using the
registry client, we _can_, it's just way more ceremony to pass down a
closure.
See: https://github.com/astral-sh/uv/issues/2346.
## Test Plan
- Verified that `cargo run pip compile
https://raw.githubusercontent.com/ansible/ansible/f1ded0f41759235eb15a7d13dbc3c95dce5d5acd/requirements.txt`
completed without error.
- Verified that `cargo run pip compile
https://raw.githubusercontent.com/ansible/ansible/f1ded0f41759235eb15a7d13dbc3c95dce5d5acd/requirements.txt
--offline` failed with an error.
- Verified that `./target/release/uv pip install requests` completed in
0-2ms, rather than hundreds.
## Summary
In #2000, I shipped a regression whereby we stopped writing relative
paths for scripts within `data` directories. The net effect here is that
we aren't _uninstalling_ binaries in all cases. (This does _not_ apply
to entrypoints, only scripts in `data` directories.)
Closes https://github.com/astral-sh/uv/issues/2330.
## Test Plan
Most Python packages ship entrypoints, not binaries, so I don't know how
to test this cheaply. But I did test it locally by verifying that `uv`
is now removed from the `bin` directory after an uninstall.
## Summary
Some zip files can't be streamed; in particular, `rs-async-zip` doesn't
support data descriptors right now (though it may in the future). This
PR adds a fallback path for such zips that downloads the entire zip file
to disk, then unzips it from disk (which gives us `Seek`).
Closes https://github.com/astral-sh/uv/issues/2216.
## Test Plan
`cargo run pip install --extra-index-url https://buf.build/gen/python
hashb_foxglove_protocolbuffers_python==25.3.0.1.20240226043130+465630478360
--force-reinstall -n`
## Summary
The netrc middleware we added in
https://github.com/astral-sh/uv/pull/2241 has a slight problem. If you
include credentials in your index URL, _and_ in the netrc file, the
crate blindly adds the netrc credentials as a header. And given the
`ReqwestBuilder` API, this means you end up with _two_ `Authorization`
headers, which always leads to an invalid request, though the exact
failure can take different forms.
This PR removes the middleware crate in favor of our own middleware.
Instead of using the `RequestInitialiser` API, we have to use the
`Middleware` API, so that we can remove the header on the request
itself.
Closes https://github.com/astral-sh/uv/issues/2323.
## Test Plan
- Verified that running against a private index with credentials in the
URL (but no netrc file) worked without error.
- Verified that running against a private index with credentials in the
netrc file (but not the URL) worked without error.
- Verified that running against a private index with a mix of
credentials in both _also_ worked without error.
## Summary
We write this a few lines down with a value passed in by the caller. I
suspect I missed that this was already here (with a less accurate value)
when adding `INSTALLER`.
`packaging==24.0` came out which broke this test. It has to run without
`--exclude-newer` since it's testing an index that doesn't support it.
Instead, though, we can just disable dependencies, since the test still
exercises the same logic.
Preparing for #2058, i found it hard to follow where which discovery
function gets called. I moved all the discovery functions to a
`find_python` module (some exposed through `PythonEnvironment`) and
documented which subcommand uses which python discovery strategy.
No functional changes.

`install_extra_index_url_has_priority` started failing because
`packaging` had a new release. I'm not sure if this preserves the index
order check as intended, but it does unblock CI.
## Summary
No behavioral changes; just taking code that's duplicated between two
branches in `distribution_database.rs` and pulling it into its own
method.
## Summary
Addressing the extremely slow performance detailed in
https://github.com/astral-sh/uv/issues/2220. There are two changes to
increase download performance:
1. setting `accept-encoding: identity`, in the spirit of
https://github.com/pypa/pip/pull/1688
2. increasing buffer from 8KiB to 128KiB.
### 1. accept-encoding: identity
I think this related `pip` PR has a good explanation of what's going on:
https://github.com/pypa/pip/pull/1688
```
# We use Accept-Encoding: identity here because requests
# defaults to accepting compressed responses. This breaks in
# a variety of ways depending on how the server is configured.
# - Some servers will notice that the file isn't a compressible
# file and will leave the file alone and with an empty
# Content-Encoding
# - Some servers will notice that the file is already
# compressed and will leave the file alone and will add a
# Content-Encoding: gzip header
# - Some servers won't notice anything at all and will take
# a file that's already been compressed and compress it again
# and set the Content-Encoding: gzip header
```
The `files.pythonhosted.org` server is the 1st kind. Example debug log I
added in `uv` when installing against PyPI:
<img width="1459" alt="image"
src="ef10d758-46aa-4c8e-9dba-47f33437401b">
(there is no `content-encoding` header in this response, the `whl`
hasn't been compressed, and there is a content-length header)
Our internal mirror is the third case. It does seem sensible that our
mirror should be modified to act like the 1st kind. But `uv` should
handle all three cases like `pip` does.
### 2. buffer increase
In https://github.com/astral-sh/uv/issues/2220 I observed that `pip`'s
downloading was causing up-to 128KiB flushes in our mirror.
After fix 1, `uv` was still only causing up-to 8KiB flushes, and was
slower to download than `pip`. Increasing this buffer from the default
8KiB led to a download performance improvement against our mirror and
the expected observed 128KiB flushes.
## Test Plan
Ran benchmarking as instructed by @charliermarsh
<img width="1447" alt="image"
src="840d9c8d-4b98-4bfa-89f3-073a2dec1f23">
No performance improvement or regression.
## Summary
In #1813, we were failing to install `scikit-image==0.19.3` from source
in Python 3.11. Confusingly, though, the trace showed that the build
command exited with status 0...
The issue is that we get results from the PEP 517 hooks by reading from
`stdout` -- that is, we `print` at the end of the script, and parse the
printed output on the other side.
It turns out that for `scikit-image`, in this case, there was output
_after_ the wheel filename:
```
...
no previously-included directories found matching 'doc/gh-pages'
adding license file 'LICENSE.txt'
writing manifest file 'scikit_image.egg-info/SOURCES.txt'
Copying scikit_image.egg-info to build/bdist.macosx-12.6-arm64/wheel/scikit_image-0.19.3-py3.11.egg-info
running install_scripts
scikit_image-0.19.3-cp311-cp311-macosx_14_0_arm64.whl
INFO:
########### EXT COMPILER OPTIMIZATION ###########
INFO: Platform :
Architecture: aarch64
Compiler : clang
CPU baseline :
Requested : 'min'
Enabled : NEON NEON_FP16 NEON_VFPV4 ASIMD
Flags : none
Extra checks: none
CPU dispatch :
Requested : 'max -xop -fma4'
Enabled : ASIMDHP ASIMDDP ASIMDFHM
Generated : none
INFO: CCompilerOpt.cache_flush[864] : write cache to path -> /private/var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmp5ZPIbv/built-wheels-v0/pypi/scikit-image/0.19.3/hLW_f7wWeGDOPRlSazQXw/scikit-image-0.19.3.tar.gz/build/temp.macosx-12.6-arm64-3.11/ccompiler_opt_cache_ext.py
```
We need the `scikit_image-0.19.3-cp311-cp311-macosx_14_0_arm64.whl`
line, but we were failing to find it due to all the extra output at the
end (presumedly, some kind of `atexit` logging).
This PR modifies the hooks to instead write their results to files that
are passed in by the parent. On the other end, we then read the results
back from disk. This makes it much more robust to "other" output in the
script.
Closes https://github.com/astral-sh/uv/issues/1813.
## Test Plan
Ran `cargo run pip install scikit-image==0.19.3 --reinstall
--no-cache-dir` on Python 3.11.
## Summary
It turns out that setuptools includes a shim to patch distutils. I'll
admit that I don't fully understand why or how it's different, but this
is the trick `pip` uses to ensure that it gets the "original" distutils.
We actually use distutils in two places: once for the system Python
scheme, and once for virtual environments. In virtualenv, they _do_ use
the patched distutils, so this could deviate in ways I don't understand.
Closes#2302.
Extends the "compatibility" types introduced in #1293 to apply to source
distributions as well as wheels.
- We now track the most-relevant incompatible source distribution
- Exclude newer, Python requirements, and yanked versions are all
tracked as incompatibilities in the new model (this lets us remove
`DistMetadata`!)
Since Python 3.7, deterministic pycs are possible (see [PEP
552](https://peps.python.org/pep-0552/))
To select the bytecode invalidation mode explicitly by env var:
PYC_INVALIDATION_MODE=UNCHECKED_HASH uv pip install --compile ...
Valid values are TIMESTAMP (default), CHECKED_HASH, and UNCHECKED_HASH.
The latter options are useful for reproducible builds.
---------
Co-authored-by: konstin <konstin@mailbox.org>
## Summary
PyPI now supports Metadata 2.2, which means distributions with Metadata
2.2-compliant metadata will start to appear. The upside is that if a
source distribution includes a `PKG-INFO` file with (1) a metadata
version of 2.2 or greater, and (2) no dynamic fields (at least, of the
fields we rely on), we can read the metadata from the `PKG-INFO` file
directly rather than running _any_ of the PEP 517 build hooks.
Closes https://github.com/astral-sh/uv/issues/2009.
This PR tweaks uv to support reading `requirements.txt` regardless of
whether it is encoded as UTF-8 or UTF-16. This is particularly relevant
on Windows where `uv pip freeze > requirements.txt` will likely write a
UTF-16 encoded `requirements.txt` file.
There is some discussion on #1666 where it's suggested that perhaps
we should explicitly not support this. I didn't see that until I
had already put this PR together, but even so, I think it's worth
considering this. UTF-16 is predominant on Windows. It is very easy
to produce a UTF-16 encoded file. Moreover, there is an easy and well
specified way to recognize and transcode UTF-16 encoded data to UTF-8.
I think the downside of this is that it could encourage the use UTF-16
encoded `requirements.txt` files *in addition* to UTF-8 encoded
files, and it would probably be nice to converge and standardize on
one encoding. One possible alternative to this PR is that we provide
a better error message. Another alternative is to ensure that a
`-o/--output` flag exists for all commands (neither `uv pip freeze` nor
`pip freeze` have such a flag) so that users can always write output
to a file without relying on their environment's piping behavior.
(Although this last alternative seems a little sad to me.)
It's also worth noting the [PEP-0508] doesn't seem to mention file
encoding at all. So I think from a "do the standards allow this"
perspective, this change is OK.
Finally, `pip` itself seems to work with UTF-16 encoded
`requirements.txt` files.
I think I personally overall lean towards supporting UTF-16 for
`requirements.txt` files. In part because I think it smoothes out the
UX a little bit, in part because there is no obvious specification
(that I'm aware of) that mandates that these files are UTF-8, and
finally in part because `pip` supports it too.
Fixes#1666, Fixes#2276
[PEP-0508]: https://peps.python.org/pep-0508/
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## Summary
refactor pip_list function to trim end of joined elements
fixed: https://github.com/astral-sh/uv/issues/2296
<!-- How was it tested? -->
## Summary
If a user provides a source distribution via a direct path, it can
either be an archive (like a `.tar.gz` or `.zip` file) or a directory.
If the former, we need to extract (e.g., unzip) the contents at some
point. Previously, this extraction was in `uv-build`; this PR lifts it
up to the distribution database.
The first benefit here is that various methods that take the
distribution are now simpler, as they can assume a directory.
The second benefit is that we no longer extract _multiple times_ when
working with a source distribution. (Previously, if we tried to get the
metadata, then fell back and built the wheel, we'd extract the wheel
_twice_.)
## Summary
This PR removes the URL conflict errors when the output of a `uv pip
compile` is used as a constraint to a subsequent `uv pip compile`.
If you run `uv pip compile`, the output file will contain your Git
dependencies, but pinned to a specific commit, like:
```
git+https://github.com/pallets/werkzeug@32e69512134c2f8183c6438b2b2e13fd24e9d19f
```
If you then use the output as a constraint to a subsequent resolution
(e.g., perhaps you require
`git+https://github.com/pallets/werkzeug@main`), we currently fail. I
think this is a reasonable workflow to support when all of these
requirements are coming from _your own_ dependencies. So we now assume
when resolving that the former is a more precise variant of the latter.
Closes https://github.com/astral-sh/uv/issues/1903.
Closes https://github.com/astral-sh/uv/issues/2266.
## Test Plan
`cargo test`