849 Commits

Author SHA1 Message Date
Charlie Marsh
1110489c29 Bump version to v0.1.3 (#1557) 2024-02-16 19:45:29 -05:00
Charlie Marsh
c1eb6130e1 Support MD5 hashes (#1556)
## Summary

We can add other hashes if necessary, but I don't know that they're
really used in practice.

Closes https://github.com/astral-sh/uv/issues/1547.
2024-02-17 00:25:16 +00:00
Charlie Marsh
9e0336c28a Remove URL encoding when determining file name (#1555)
## Summary

Closes https://github.com/astral-sh/uv/issues/1553.
2024-02-16 19:15:24 -05:00
Charlie Marsh
6392961f44 Add support for extras in editable requirements (#1531)
## Summary

If you're developing on a package like `attrs` locally, and it has a
recursive extra like `attrs[dev]`, it turns out that we then try to find
the `attrs` in `attrs[dev]` from the registry, rather than recognizing
that it's part of the editable.

This PR fixes the issue by making editables slightly more first-class
throughout the resolver. Instead of mocking metadata, we explicitly
check for extras in various places. Part of the problem here is that we
treated editables as URL dependencies, but when we saw an _extra_ like
`attrs[dev]`, we didn't map that back to the URL. So now, we treat them
as registry dependencies, but with the appropriate guardrails
throughout.

Closes https://github.com/astral-sh/uv/issues/1447.

## Test Plan

- Cloned `attrs`.
- Ran `cargo run venv && cargo run pip install -e ".[dev]" -v`.
2024-02-16 18:48:35 -05:00
Charlie Marsh
4e0b6f8f84 Avoid attempting rename in copy fallback path (#1546)
## Summary

This _could_ fix https://github.com/astral-sh/uv/issues/1454, but I'm
not sure. I was able to replicate by forcing a bunch of error states.
But, in short, if we fail to hardlink on the initial copy due to a file
existing, and then fail _again_, we fallback to copying. But if we copy,
then the tempfile doesn't exist, and so the `fs_err::rename(&tempfile,
&out_path)?;` will fail with "File not found".

This PR just ensures that the cases are explicitly mutually exclusive:
we only attempt to rename if the hardlink succeeded.
2024-02-16 17:08:49 -05:00
David Szotten
8050370717 Fix trailing commas on Requires-Python in HTML indexes (#1507)
illustration and suggested fix for #1464
2024-02-16 22:05:28 +00:00
Charlie Marsh
4f216f3a74 Apply percent-decoding to filepaths in HTML find-links (#1544)
## Summary

Closes https://github.com/astral-sh/uv/issues/1542.
2024-02-16 16:47:04 -05:00
Andrew Gallant
3aa7a6b796 fix OS detection for Alpine Linux (#1545)
This PR fixes the OS detection for Alpine Linux such that the version
of musl available is correctly determined. The issue boiled down to
a regex that required 2 digits for each version component. But a
valid musl version is 1.2.4, which only has a single digit for each
component.

It's unclear how this was working for musl before this change. My
theory is that our other methods of OS detection were somehow working.

The first commit in this PR cleans up our Linux detection logic and adds
lots of tracing calls to make debugging issues like this easier in the
future. To do so, one can run:

    $ RUST_LOG=trace uv pip install -v whatever

The second commit has the actual fix.

Fixes #1427
2024-02-16 16:37:18 -05:00
Charlie Marsh
b4ea48955b Use comparable representation for PackageId (#1543)
## Summary

By using the display representation of `Version` to form a `PackageId`,
we run the risk (as seen in the linked issue) of thinking that versions
like `2021.1` and `2021.1.0` are not equivalent.

Closes https://github.com/astral-sh/uv/issues/1536
2024-02-16 16:30:54 -05:00
Charlie Marsh
01ffc36520 Apply percent-decoding to file-based URLs (#1541)
## Summary

Closes https://github.com/astral-sh/uv/issues/1537.
2024-02-16 16:11:16 -05:00
Andrew Gallant
a97c207674 pypi-types: fix lenient requirement parsing (#1529)
This fixes a bug where `uv pip install` failed to install `polars`:

```
$ uv pip install polars==0.14.0
error: Failed to download: polars==0.14.0
  Caused by: Couldn't parse metadata of polars-0.14.0-cp37-abi3-manylinux_2_12_x86_64.manylinux2010_x86_64.whl from 749022b096/polars-0.14.0-cp37-abi3-manylinux_2_12_x86_64.manylinux2010_x86_64.whl
  Caused by: Operator >= cannot be used with a wildcard version specifier
pyarrow>=4.0.*; extra == 'pyarrow'
       ^^^^^^^
```

Since `pyarrow>=4.0.*; extra == 'pyarrow'` is invalid *and* it comes
from the metadata of a dependency (that isn't under the control of the
end user), we actually attempt to "fix" it. Namely, wildcard
dependency specifications are only allowed with `==` and `!=`, as per
the [Version Specifiers spec]. (They aren't explicitly forbidden in
these cases, but instead only have specified behavior for the `==` and
`!=` operators.)

This is all fine, but it turns out that when we fix the `>=4.0.*`
component, we also strip the quotes around `pyarrow`. (Because some
dependency specifications include stray quotes.) We fix this by making
our quote stripping a bit more selective. (We require that it appear
adjacent to a digit or a `*`.)

Note that #1477 also reports this error:

```
$ uv pip install 'requests>=2.30.*'
error: Failed to parse `requests>=2.30.*`
  Caused by: Operator >= cannot be used with a wildcard version specifier
requests>=2.30.*
```

However, we specifically keep that error message since it's something
under the end user's control. And similarly for a dependency
specification in a `requirements.txt` file.

Fixes #1477

[Version Specifiers spec]:
https://packaging.python.org/en/latest/specifications/version-specifiers/
2024-02-16 15:52:44 -05:00
Zanie Blue
d5e8531ae3 Add support for UV_EXTRA_INDEX_URL (#1515)
Closes https://github.com/astral-sh/uv/issues/1450
2024-02-16 12:54:58 -06:00
Zanie Blue
2ea44d863a Add warning for empty requirements files (#1519)
Also, improve tracing of requirements file parsing.

Per my confusion in #1334
2024-02-16 18:19:09 +00:00
Zanie Blue
89ad1c6fa1 Add pip install --constraint test coverage (#1334)
Exploring behavior reported in
https://github.com/astral-sh/uv/issues/1332
2024-02-16 17:39:39 +00:00
Charlie Marsh
f25781ff6c Support recursive extras (#1435)
## Summary

We had a guard in the resolve to avoid "self-dependencies" (as in
`gps3==0.33.3`), but this guard was _unintentionally_ filtering out
recursive extras.

Closes https://github.com/astral-sh/uv/issues/1342.

## Test Plan

Taken from https://github.com/astral-sh/uv/pull/1352.
2024-02-16 11:42:04 -05:00
Zanie Blue
e6c4c77ba1 Use string display instead of debug for url parse trace (#1498)
e.g. 

`uv_client::html::parse
url=https://download.pytorch.org/whl/torch_stable.html`

instead of

`uv_client::html::parse url=Url { scheme: "https", cannot_be_a_base:
false, username: "", password: None, host:
Some(Domain("download.pytorch.org")), port: None, path:
"/whl/torch_stable.html", query: None, fragment: None }`
2024-02-16 15:13:16 +00:00
Andrew Gallant
67cde15420 only parse /bin/sh (not /bin/ls) (#1493)
It turns out that /bin/ls can sometimes be plain text file. For
example, in Rocky Linux 9:

```
$ cat /bin/ls
#!/usr/bin/coreutils --coreutils-prog-shebang=ls
```

However, `/bin/sh` is an ELF binary:

```
$ file /bin/sh
/bin/sh: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=7acbb41bf6f1b7d977f1b44675bf3ed213776835, for GNU/Linux 3.2.0, stripped
```

In a related issue (#1433), @zanieb fixed #1395 where, on NixOS,
`/bin/ls` doesn't exist but `/bin/sh` does. However, the fix attempts
`/bin/ls` first and only tries `/bin/sh` if `/bin/ls` doesn't exist. If
`/bin/ls` exists but isn't a valid ELF file, then the entire enterprise
gives up and `uv` fails to detect the version of `libc` that is
installed.

Instead of tweaking the logic to keep trying `/bin/ls` and then
`/bin/sh` after even if parsing `/bin/ls` fails, we just switch over to
reading `/bin/sh` only. It seems like a more fundamental thing to sniff
and likely less error prone.

We can adjust this heuristic as needed if it provdes to be problematic.

I tested this fix manually on Rocky Linux 9 via Docker:

```
$ cross b -r -p uv --target x86_64-unknown-linux-musl
$ cp target/x86_64-unknown-linux-musl/release/uv ~/astral/issues/uv/i1486/uv
$ docker run --rm -it --mount type=bind,src=/home/andrew/astral/issues/uv/i1486,dst=/host rockylinux:9 bash
[root@df2baa65d2f8 /]# /host/uv venv
Using Python 3.9.18 interpreter at /usr/bin/python3.9
Creating virtualenv at: .venv
[root@df2baa65d2f8 /]#
```

Fixes #1486, Ref #1433
2024-02-16 09:44:47 -05:00
Micha Reiser
e913167849 Fix list rendering in venv --help output (#1459) 2024-02-16 15:36:36 +01:00
Aarni Koskela
3280562e3a Loosen package script regexp to match spec (#1482)
Fixes #1479.
2024-02-16 09:25:32 -05:00
Zanie Blue
d99c4cacdf Read from /bin/sh if /bin/ls cannot be found when determing libc path (#1433)
I'm not sure if we should just switch to _always_ reading from sh
instead? I don't love that all these errors are strings and I if
`/bin/ls` exists but can't be parsed we still won't try `/bin/sh`. We
may want to address these things in the future.

Closes https://github.com/astral-sh/uv/issues/1395
2024-02-16 07:51:34 -05:00
Charlie Marsh
c474370064 Allow empty fragments in HTML parser (#1443)
## Summary

It looks like `devpi` might add an empty fragment (`#`) at the end of
the URL. We expect it to contain the hash; this just makes
empty-fragment map to "no hash".

Closes https://github.com/astral-sh/uv/issues/1441.
2024-02-16 06:42:21 +00:00
Charlie Marsh
659327f24a Bump version to v0.1.2 (#1439) 2024-02-16 01:17:19 -05:00
Charlie Marsh
0d005a2a71 Decode HTML escapes when extracting SHA (#1440)
## Summary

If a distribution contains a `+`, it'll be HTML-escaped; so when we try
to identify the `#`, we'll split in the wrong location.

Closes https://github.com/astral-sh/uv/issues/1338.
2024-02-16 06:15:51 +00:00
Charlie Marsh
958e88ddbf Ignore invalid extra named .none (#1428)
## Summary

Some packages erroneously include an extra named `.none`. It turns out
that certain versions of `flit` included this by accident:
https://github.com/pypa/flit/issues/228/.

This PR adds leniency for that specific extra name.

Closes https://github.com/astral-sh/uv/issues/1363.

Closes https://github.com/astral-sh/uv/issues/1399.
2024-02-16 05:01:21 +00:00
Zanie Blue
0bfce353fb Fix broken URLs parsed from relative paths in registries (#1413)
Closes https://github.com/astral-sh/uv/issues/1388

Fixes incorrect handling of relative paths returned by indexes without
an explicit `<base>`.

`Url.join` will drop the last segment in an url e.g. `http://foo/bar` ->
`http://foo/baz` if there is not a trailing slash but what we want is
`http://foo/bar/baz`. We don't add the trailing `/` in
`base_url_join_relative` because flat indexes are `http://foo/bar.html`
and we _want_ `bar.html` to be replaced.
2024-02-15 22:37:09 -06:00
Charlie Marsh
e48edf02fa Parse -r and -c entries as relative to containing file (#1421)
## Summary

In a `requirements.txt` file, it turns out that the `-c` and `-r`
entries should be interpreted as relative to the file in which they're
declared, while the `-e` entries should be interpreted as relative to
the current working directory, no matter where they're defined.

Previously, we always used the current working directory; now, we use
the declaring file's directory for `-c` and `-r`.

Closes https://github.com/astral-sh/uv/issues/1367.

Closes https://github.com/astral-sh/uv/issues/1416.
2024-02-15 23:19:43 -05:00
Charlie Marsh
1837641138 Add fix-up for invalid star comparison with major-only version (#1410)
## Summary

Closes https://github.com/astral-sh/uv/issues/1402.

## Test Plan

Ran `cargo run pip install junos-eznc==2.6.5`, which still fails for me,
but fails identically to `pip` (and not on the `requires-python`):

```
/private/var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmp7mxT9L/built-wheels-v0/pypi/ncclient/0.6.13/4vvPwmDC_CL2OUXd68Zqb/ncclient-0.6.13.tar.gz/versioneer.py:421: SyntaxWarning: invalid escape sequence '\s'
  LONG_VERSION_PY['git'] = '''
Traceback (most recent call last):
  File "<string>", line 10, in <module>
  File "/private/var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmplD5mMO/.venv/lib/python3.12/site-packages/setuptools/build_meta.py", line 366, in prepare_metadata_for_build_wheel
    self.run_setup()
  File "/private/var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmplD5mMO/.venv/lib/python3.12/site-packages/setuptools/build_meta.py", line 480, in run_setup
    super().run_setup(setup_script=setup_script)
  File "/private/var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmplD5mMO/.venv/lib/python3.12/site-packages/setuptools/build_meta.py", line 311, in run_setup
    exec(code, locals())
  File "<string>", line 45, in <module>
  File "/private/var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmp7mxT9L/built-wheels-v0/pypi/ncclient/0.6.13/4vvPwmDC_CL2OUXd68Zqb/ncclient-0.6.13.tar.gz/versioneer.py", line 1480, in get_version
    return get_versions()["version"]
           ^^^^^^^^^^^^^^
  File "/private/var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmp7mxT9L/built-wheels-v0/pypi/ncclient/0.6.13/4vvPwmDC_CL2OUXd68Zqb/ncclient-0.6.13.tar.gz/versioneer.py", line 1412, in get_versions
    cfg = get_config_from_root(root)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/private/var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmp7mxT9L/built-wheels-v0/pypi/ncclient/0.6.13/4vvPwmDC_CL2OUXd68Zqb/ncclient-0.6.13.tar.gz/versioneer.py", line 342, in get_config_from_root
    parser = configparser.SafeConfigParser()
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'configparser' has no attribute 'SafeConfigParser'. Did you mean: 'RawConfigParser'?
```
2024-02-16 02:12:10 +00:00
Charlie Marsh
7994b68654 Add fix-up for trailing comma with trailing space (#1409)
## Summary

Closes https://github.com/astral-sh/uv/issues/1361.

## Test Plan

```text
Resolved 3 packages in 243ms
Downloaded 3 packages in 193ms
Installed 3 packages in 6ms
 + et-xmlfile==1.1.0
 + jdcal==1.4.1
 + openpyxl==3.0.5
```
2024-02-16 02:08:05 +00:00
Zanie Blue
0f554b0913 Add -U/-P short flags for --upgrade/--upgrade-package (#1394)
Closes https://github.com/astral-sh/uv/issues/1340
2024-02-16 01:34:19 +00:00
Zanie Blue
896ab1c54f Add --upgrade support to pip install (#1379)
Adds support for `--upgrade` — similar to `--reinstall`.

Closes https://github.com/astral-sh/uv/issues/1391
2024-02-15 19:25:28 -06:00
Shantanu
e9d82cf0fa Avoid import contextlib in _virtualenv (#1406)
No need to pay 3ms on basically every Python invocation. I opened a PR
upstream last week: https://github.com/pypa/virtualenv/pull/2688
2024-02-15 20:23:05 -05:00
Robin Krahl
f9a9f53476 Improve error message for invalid sdist archives (#1389)
This PR improves the error message for the problem described in
https://github.com/astral-sh/uv/issues/1376. The original output
duplicates the actual error message and includes lots of noise
(`DirEntry { inner: DirEntry(...) }`).

```
$ uv pip install hexdump==3.3
error: Failed to download and build: hexdump==3.3
  Caused by: Failed to extract source distribution: The top level of the archive must only contain a list directory, but it contains: [DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/__main__.py") }, DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/hexdump.py") }, DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/data") }, DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/PKG-INFO") }, DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/setup.py") }, DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/README.txt") }]
  Caused by: The top level of the archive must only contain a list directory, but it contains: [DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/__main__.py") }, DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/hexdump.py") }, DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/data") }, DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/PKG-INFO") }, DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/setup.py") }, DirEntry { inner: DirEntry("/home/robin/.cache/uv/.tmpgSvTCk/README.txt") }]
```

This PR removes the duplication and `DirEntry` internals so that the
error message is easier to grasp:

```
$ uv pip install hexdump==3.3
error: Failed to download and build: hexdump==3.3
  Caused by: Failed to extract source distribution
  Caused by: The top level of the archive must only contain a list directory, but it contains: ["__main__.py", "hexdump.py", "data", "PKG-INFO", "setup.py", "README.txt"]
```
2024-02-15 18:03:23 -06:00
Zanie Blue
c6a43e92f9 Add UV_NO_CACHE environment variable (#1383)
It's a little picky about the value, but that seems okay.

```
❯ ./target/debug/uv pip install trio
Audited 1 package in 4ms
❯ UV_NO_CACHE=true ./target/debug/uv pip install trio
Audited 1 package in 50ms
```

Closes #1382
2024-02-15 23:34:42 +00:00
mikcl
fbd6d87214 uv-cache: Add hidden alias for --no-cache-dir (#1380)
This is for compatability with pip install --no-cache-dir

Closes https://github.com/astral-sh/uv/issues/1373

Signed-off-by: mikcl <mikesmikes400@gmail.com>
2024-02-15 23:26:16 +00:00
Zanie Blue
18a7c079de Fix search for python.exe on Windows (#1381)
A la #1351
2024-02-15 17:25:20 -06:00
Zanie Blue
e0885b7c8e Bump version to 0.1.1 (#1359) 2024-02-15 15:38:22 -06:00
Yannik Sander
36544e1678 Fix diagram alignment (#1354)
Drive by alignment PR for the trait structure diagram
2024-02-15 15:32:33 -06:00
Zanie Blue
102e5ddfbe Fix bug where python3 is not found in the global path (#1351)
When we refactored handling for Windows tests, we accidentally dropped
`python3` from path searches.
2024-02-15 15:29:33 -06:00
Charlie Marsh
27177613d4 Bump version to v0.1.0 (#1325) 2024-02-15 14:12:23 -05:00
Zanie Blue
0780afff95 Rename PUFFIN environment variables to UV (#1319)
A couple of these are actually user-facing although undocumented
2024-02-15 12:49:27 -06:00
Charlie Marsh
0579a04014 Bump to v0.0.5 for pre-release (#1324)
This is easier than figuring out the version parsing.
2024-02-15 18:33:34 +00:00
Charlie Marsh
ad12d97e71 Set crate to prerelease (#1320) 2024-02-15 18:21:09 +00:00
Charlie Marsh
06f2b6eee2 Bump version and update pyproject.toml metadata (#1316)
Also ensures that we no longer clear the README when uploading to PyPI
:)
2024-02-15 18:03:35 +00:00
Charlie Marsh
55808a451f Regenerate benchmarks (#1305) 2024-02-15 17:54:04 +00:00
Zanie Blue
2586f655bb Rename to uv (#1302)
First, replace all usages in files in-place. I used my editor for this.
If someone wants to add a one-liner that'd be fun.

Then, update directory and file names:

```
# Run twice for nested directories
find . -type d -print0 | xargs -0 rename s/puffin/uv/g
find . -type d -print0 | xargs -0 rename s/puffin/uv/g

# Update files
find . -type f -print0 | xargs -0 rename s/puffin/uv/g
```

Then add all the files again

```
# Add all the files again
git add crates
git add python/uv

# This one needs a force-add
git add -f crates/uv-trampoline
```
2024-02-15 11:19:46 -06:00
Zanie Blue
e9e3e573a2 Report incompatible distributions to users (#1293)
Instead of dropping versions without a compatible distribution, we track
them as incompatibilities in the solver. This implementation follows
patterns established in https://github.com/astral-sh/puffin/pull/1290.

This required some significant refactoring of how we track incompatible
distributions. Notably:

- `Option<TagPriority>` is now `WheelCompatibility` which allows us to
track the reason a wheel is incompatible instead of just `None`.
- `Candidate` now has a `CandidateDist` with `Compatible` and
`Incompatibile` variants instead of just `ResolvableDist`; candidates
are not strictly compatible anymore
- `ResolvableDist` was renamed to `CompatibleDist`
- `IncompatibleWheel` was given an ordering implementation so we can
track the "most compatible" (but still incompatible) wheel. This allows
us to collapse the reason a version cannot be used to a single
incompatibility.
- The filtering in the `VersionMap` is retained, we still only store one
incompatible wheel per version. This is sufficient for error reporting.
- A `TagCompatibility` type was added for tracking which part of a wheel
tag is incompatible
- `Candidate::validate_python` moved to
`PythonRequirement::validate_dist`

I am doing more refactoring in #1298 — I think a couple passes will be
necessary to clarify the relationships of these types.

Includes improved error message snapshots for multiple incompatible
Python tag types from #1285 — we should add more scenarios for coverage
of behavior when multiple tags with different levels are present.
2024-02-15 10:48:15 -06:00
Andrew Gallant
b6fba00153 cli: conventionally treat - as "read from stdin" (#1314)
Basically, when a path to a requirements file is `-`, then we should
read its contents from `stdin` instead of the file path named `-`.

Fixes #1313
2024-02-15 11:25:56 -05:00
Armin Ronacher
bf2ee6bc31 Adds support for --no-deps to pip compile (#1311)
Mostly throwing this up here as a discussion topic. Having something
like this is primarily useful for enabling use cases similar to `rye
add` where I want to use this currently. One can accomplish something
similar with `unearth` today or by abusing regular `pip install`:

```
$ ~/.rye/self/bin/pip install --no-deps --dry-run flask --report - -q | jq '.install[0].metadata | {name, version}'
{
  "name": "Flask",
  "version": "3.0.2"
}
```

Another option would be to have a `puffin resolve` command or similar
that works like `pip compile` without dependencies, takes the
requirements as arguments and returns a line for each resolution. That
would be a larger change.
2024-02-15 09:01:31 -05:00
Andrew Gallant
94437175c7 puffin-resolver: make VersionMap::iter even lazier
This rollbacks the optimization in the previous commit to be more
general. That is, instead of specializing the case of a range for a
singleton version, we make iteration over the distributions in a
`VersionMap` more explicitly lazy. Iteration now provides a `Version`
(like it did previously) and a _handle_ to a distribution that can be
turned into a `ResolvableDist`.

Doing things this way permits callers to iterate over the versions and
only materialize a distribution if they actually need one. In cases like
candidate selection, one can often rule out use of a distribution
through its version alone, and thus skip construction of that
distribution entirely.
2024-02-15 08:10:32 -05:00
Andrew Gallant
ed000d0dd5 puffin-resolver: add singleton fast path
In many cases, version ranges are actually just pins to a
specific and single version. And we can detect that statically
by examining the range. If we do have a range that is just one
version, then we can ask a `VersionMap` for just that version
instead of iterating over what's in the map until we find one
that satisfies the range.

I had tried this before making `VersionMap` construction lazy,
but it didn't seem to matter much. But helps a lot more now
with a lazy `VersionMap` because it lets us avoid creating a
lot of distributions in memory that we won't ultimately use.
2024-02-15 08:10:32 -05:00