Extract local versions from direct URL requirements (#2624)

## Summary

Closes https://github.com/astral-sh/uv/issues/2623.

## Test Plan

`cargo run pip install -r requirements.txt`, with:

```
 whisperX @ https://github.com/m-bain/whisperX/archive/befe2b242eb59dcd7a8a122d127614d5c63d36e9.zip
 pyannote-audio @ git+https://github.com/pyannote/pyannote-audio@11b56a137a578db9335efc00298f6ec1932e6317
 torch @ https://download.pytorch.org/whl/cu118/torch-2.2.1%2Bcu118-cp311-cp311-linux_x86_64.whl#sha256=84328a35621cc6a67a182a327baaab67e5f5869981c4b1677ed05f92c15cceb1
 torchaudio @ https://download.pytorch.org/whl/cu118/torchaudio-2.2.1%2Bcu118-cp311-cp311-linux_x86_64.whl#sha256=cd3b1c3582b17792c6d7a367dea0459b123e54d7a4242809ea87ccc10fa220e5
 pytorch_triton @ https://download.pytorch.org/whl/nightly/pytorch_triton-2.1.0%2B7d1a95b046-cp311-cp311-linux_x86_64.whl
```

crates/uv-resolver/src/resolver/locals.rs

@@ -1,5 +1,10 @@
+use std::str::FromStr;
+
+use either::Either;
 use rustc_hash::FxHashMap;
 
+use distribution_filename::{SourceDistFilename, WheelFilename};
+use distribution_types::RemoteSource;
 use pep440_rs::{Operator, Version, VersionSpecifier, VersionSpecifierBuildError};
 use pep508_rs::{MarkerEnvironment, VersionOrUrl};
 use uv_normalize::PackageName;
@@ -42,13 +47,9 @@ impl Locals {
                     .filter(|requirement| requirement.evaluate_markers(markers, &[])),
             )
         {
-            if let Some(VersionOrUrl::VersionSpecifier(specifiers)) =
-                requirement.version_or_url.as_ref()
-            {
-                for specifier in specifiers.iter() {
-                    if let Some(version) = to_local(specifier) {
-                        required.insert(requirement.name.clone(), version.clone());
-                    }
+            if let Some(version_or_url) = requirement.version_or_url.as_ref() {
+                for local in iter_locals(version_or_url) {
+                    required.insert(requirement.name.clone(), local);
                 }
             }
         }
@@ -158,18 +159,48 @@ fn is_compatible(expected: &Version, provided: &Version) -> bool {
     }
 }
 
-/// If a [`VersionSpecifier`] represents exact equality against a local version, return the local
-/// version.
-fn to_local(specifier: &VersionSpecifier) -> Option<&Version> {
-    if !matches!(specifier.operator(), Operator::Equal | Operator::ExactEqual) {
-        return None;
-    };
-
-    if specifier.version().local().is_empty() {
-        return None;
+/// If a [`VersionSpecifier`] contains exact equality specifiers for a local version, returns an
+/// iterator over the local versions.
+fn iter_locals(version_or_url: &VersionOrUrl) -> impl Iterator<Item = Version> + '_ {
+    match version_or_url {
+        // Extract all local versions from specifiers that require an exact version (e.g.,
+        // `==1.0.0+local`).
+        VersionOrUrl::VersionSpecifier(specifiers) => Either::Left(
+            specifiers
+                .iter()
+                .filter(|specifier| {
+                    matches!(specifier.operator(), Operator::Equal | Operator::ExactEqual)
+                })
+                .filter(|specifier| !specifier.version().local().is_empty())
+                .map(|specifier| specifier.version().clone()),
+        ),
+        // Exact a local version from a URL, if it includes a fully-qualified filename (e.g.,
+        // `torch-2.2.1%2Bcu118-cp311-cp311-linux_x86_64.whl`).
+        VersionOrUrl::Url(url) => Either::Right(
+            url.filename()
+                .ok()
+                .and_then(|filename| {
+                    if let Ok(filename) = WheelFilename::from_str(&filename) {
+                        if filename.version.is_local() {
+                            Some(filename.version)
+                        } else {
+                            None
+                        }
+                    } else if let Ok(filename) =
+                        SourceDistFilename::parsed_normalized_filename(&filename)
+                    {
+                        if filename.version.is_local() {
+                            Some(filename.version)
+                        } else {
+                            None
+                        }
+                    } else {
+                        None
+                    }
+                })
+                .into_iter(),
+        ),
     }
-
-    Some(specifier.version())
 }
 
 #[cfg(test)]
@@ -177,10 +208,53 @@ mod tests {
     use std::str::FromStr;
 
     use anyhow::Result;
+    use url::Url;
 
-    use pep440_rs::{Operator, Version, VersionSpecifier};
+    use pep440_rs::{Operator, Version, VersionSpecifier, VersionSpecifiers};
+    use pep508_rs::{VerbatimUrl, VersionOrUrl};
 
-    use super::Locals;
+    use crate::resolver::locals::{iter_locals, Locals};
+
+    #[test]
+    fn extract_locals() -> Result<()> {
+        // Extract from a source distribution in a URL.
+        let version_or_url = VersionOrUrl::Url(VerbatimUrl::from_url(Url::parse(
+            "https://example.com/foo-1.0.0+local.tar.gz",
+        )?));
+        let locals: Vec<_> = iter_locals(&version_or_url).collect();
+        assert_eq!(locals, vec![Version::from_str("1.0.0+local")?]);
+
+        // Extract from a wheel in a URL.
+        let version_or_url = VersionOrUrl::Url(VerbatimUrl::from_url(Url::parse(
+            "https://example.com/foo-1.0.0+local-cp39-cp39-linux_x86_64.whl",
+        )?));
+        let locals: Vec<_> = iter_locals(&version_or_url).collect();
+        assert_eq!(locals, vec![Version::from_str("1.0.0+local")?]);
+
+        // Don't extract anything if the URL is opaque.
+        let version_or_url = VersionOrUrl::Url(VerbatimUrl::from_url(Url::parse(
+            "git+https://example.com/foo/bar",
+        )?));
+        let locals: Vec<_> = iter_locals(&version_or_url).collect();
+        assert!(locals.is_empty());
+
+        // Extract from `==` specifiers.
+        let version_or_url = VersionOrUrl::VersionSpecifier(VersionSpecifiers::from_iter([
+            VersionSpecifier::from_version(Operator::GreaterThan, Version::from_str("1.0.0")?)?,
+            VersionSpecifier::from_version(Operator::Equal, Version::from_str("1.0.0+local")?)?,
+        ]));
+        let locals: Vec<_> = iter_locals(&version_or_url).collect();
+        assert_eq!(locals, vec![Version::from_str("1.0.0+local")?]);
+
+        // Ignore other specifiers.
+        let version_or_url = VersionOrUrl::VersionSpecifier(VersionSpecifiers::from_iter([
+            VersionSpecifier::from_version(Operator::NotEqual, Version::from_str("1.0.0+local")?)?,
+        ]));
+        let locals: Vec<_> = iter_locals(&version_or_url).collect();
+        assert!(locals.is_empty());
+
+        Ok(())
+    }
 
     #[test]
     fn map_version() -> Result<()> {