Allow Git URLs

crates/cache-key/src/canonical_url.rs

@@ -91,6 +91,12 @@ impl Hash for CanonicalUrl {
     }
 }
 
+impl From<CanonicalUrl> for Url {
+    fn from(value: CanonicalUrl) -> Self {
+        value.0
+    }
+}
+
 impl std::fmt::Display for CanonicalUrl {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         std::fmt::Display::fmt(&self.0, f)

crates/uv-distribution/src/git.rs

@@ -8,6 +8,7 @@ use rustc_hash::FxHashMap;
 use tracing::debug;
 use url::Url;
 
+use cache_key::CanonicalUrl;
 use distribution_types::DirectGitUrl;
 use uv_cache::{Cache, CacheBucket};
 use uv_fs::LockedFile;
@@ -91,9 +92,8 @@ pub(crate) async fn resolve_precise(
     cache: &Cache,
     reporter: Option<&Arc<dyn Reporter>>,
 ) -> Result<Option<Url>, Error> {
-    let git_dir = cache.bucket(CacheBucket::Git);
-
-    let DirectGitUrl { url, subdirectory } = DirectGitUrl::try_from(url).map_err(Error::Git)?;
+    let url = Url::from(CanonicalUrl::new(url));
+    let DirectGitUrl { url, subdirectory } = DirectGitUrl::try_from(&url).map_err(Error::Git)?;
 
     // If the Git reference already contains a complete SHA, short-circuit.
     if url.precise().is_some() {
@@ -111,6 +111,8 @@ pub(crate) async fn resolve_precise(
         }
     }
 
+    let git_dir = cache.bucket(CacheBucket::Git);
+
     // Fetch the precise SHA of the Git reference (which could be a branch, a tag, a partial
     // commit, etc.).
     let source = if let Some(reporter) = reporter {
@@ -135,3 +137,134 @@ pub(crate) async fn resolve_precise(
         subdirectory,
     })))
 }
+
+/// Returns `true` if the URLs refer to the same Git commit.
+///
+/// For example, the previous URL could be a branch or tag, while the current URL would be a
+/// precise commit hash.
+pub fn is_same_reference<'a>(a: &'a Url, b: &'a Url) -> bool {
+    let resolved_git_refs = RESOLVED_GIT_REFS.lock().unwrap();
+    is_same_reference_impl(a, b, &resolved_git_refs)
+}
+
+/// Returns `true` if the URLs refer to the same Git commit.
+///
+/// Like [`is_same_reference`], but accepts a resolved reference cache for testing.
+fn is_same_reference_impl<'a>(
+    a: &'a Url,
+    b: &'a Url,
+    resolved_refs: &FxHashMap<GitUrl, GitUrl>,
+) -> bool {
+    // Convert `a` to a Git URL, if possible.
+    let Ok(a_git) = DirectGitUrl::try_from(&Url::from(CanonicalUrl::new(a))) else {
+        return false;
+    };
+
+    // Convert `b` to a Git URL, if possible.
+    let Ok(b_git) = DirectGitUrl::try_from(&Url::from(CanonicalUrl::new(b))) else {
+        return false;
+    };
+
+    // The URLs must refer to the same subdirectory, if any.
+    if a_git.subdirectory != b_git.subdirectory {
+        return false;
+    }
+
+    // The URLs must refer to the same repository.
+    if a_git.url.repository() != b_git.url.repository() {
+        return false;
+    }
+
+    // If the URLs have the same tag, they refer to the same commit.
+    if a_git.url.reference() == b_git.url.reference() {
+        return true;
+    }
+
+    // Otherwise, the URLs must resolve to the same precise commit.
+    let Some(a_precise) = a_git
+        .url
+        .precise()
+        .or_else(|| resolved_refs.get(&a_git.url).and_then(GitUrl::precise))
+    else {
+        return false;
+    };
+
+    let Some(b_precise) = b_git
+        .url
+        .precise()
+        .or_else(|| resolved_refs.get(&b_git.url).and_then(GitUrl::precise))
+    else {
+        return false;
+    };
+
+    a_precise == b_precise
+}
+
+#[cfg(test)]
+mod tests {
+    use anyhow::Result;
+    use rustc_hash::FxHashMap;
+    use url::Url;
+
+    use uv_git::GitUrl;
+
+    #[test]
+    fn same_reference() -> Result<()> {
+        let empty = FxHashMap::default();
+
+        // Same repository, same tag.
+        let a = Url::parse("git+https://example.com/MyProject.git@main")?;
+        let b = Url::parse("git+https://example.com/MyProject.git@main")?;
+        assert!(super::is_same_reference_impl(&a, &b, &empty));
+
+        // Same repository, same tag, same subdirectory.
+        let a = Url::parse("git+https://example.com/MyProject.git@main#subdirectory=pkg_dir")?;
+        let b = Url::parse("git+https://example.com/MyProject.git@main#subdirectory=pkg_dir")?;
+        assert!(super::is_same_reference_impl(&a, &b, &empty));
+
+        // Different repositories, same tag.
+        let a = Url::parse("git+https://example.com/MyProject.git@main")?;
+        let b = Url::parse("git+https://example.com/MyOtherProject.git@main")?;
+        assert!(!super::is_same_reference_impl(&a, &b, &empty));
+
+        // Same repository, different tags.
+        let a = Url::parse("git+https://example.com/MyProject.git@main")?;
+        let b = Url::parse("git+https://example.com/MyProject.git@v1.0")?;
+        assert!(!super::is_same_reference_impl(&a, &b, &empty));
+
+        // Same repository, same tag, different subdirectory.
+        let a = Url::parse("git+https://example.com/MyProject.git@main#subdirectory=pkg_dir")?;
+        let b = Url::parse("git+https://example.com/MyProject.git@main#subdirectory=other_dir")?;
+        assert!(!super::is_same_reference_impl(&a, &b, &empty));
+
+        // Same repository, different tags, but same precise commit.
+        let a = Url::parse("git+https://example.com/MyProject.git@main")?;
+        let b = Url::parse(
+            "git+https://example.com/MyProject.git@164a8735b081663fede48c5041667b194da15d25",
+        )?;
+        let mut resolved_refs = FxHashMap::default();
+        resolved_refs.insert(
+            GitUrl::try_from(Url::parse("https://example.com/MyProject@main")?)?,
+            GitUrl::try_from(Url::parse(
+                "https://example.com/MyProject@164a8735b081663fede48c5041667b194da15d25",
+            )?)?,
+        );
+        assert!(super::is_same_reference_impl(&a, &b, &resolved_refs));
+
+        // Same repository, different tags, different precise commit.
+        let a = Url::parse("git+https://example.com/MyProject.git@main")?;
+        let b = Url::parse(
+            "git+https://example.com/MyProject.git@164a8735b081663fede48c5041667b194da15d25",
+        )?;
+        let mut resolved_refs = FxHashMap::default();
+        resolved_refs.insert(
+            GitUrl::try_from(Url::parse("https://example.com/MyProject@main")?)?,
+            GitUrl::try_from(Url::parse(
+                "https://example.com/MyProject@f2c9e88f3ec9526bbcec68d150b176d96a750aba",
+            )?)?,
+        );
+        assert!(!super::is_same_reference_impl(&a, &b, &resolved_refs));
+
+        Ok(())
+    }
+}

crates/uv-distribution/src/lib.rs

@@ -1,6 +1,7 @@
 pub use distribution_database::DistributionDatabase;
 pub use download::{BuiltWheel, DiskWheel, LocalWheel};
 pub use error::Error;
+pub use git::is_same_reference;
 pub use index::{BuiltWheelIndex, RegistryWheelIndex};
 pub use reporter::Reporter;
 pub use source::{download_and_extract_archive, SourceDistributionBuilder};

crates/uv-git/src/lib.rs

@@ -47,6 +47,11 @@ impl GitUrl {
         }
     }
 
+    /// Returns `true` if the reference is a full commit.
+    pub fn is_full_commit(&self) -> bool {
+        matches!(self.reference, GitReference::FullCommit(_))
+    }
+
     /// Return the precise commit, if known.
     pub fn precise(&self) -> Option<GitSha> {
         self.precise

crates/uv-requirements/src/lookahead.rs

@@ -4,7 +4,6 @@ use anyhow::{Context, Result};
 use cache_key::CanonicalUrl;
 use futures::stream::FuturesUnordered;
 use futures::StreamExt;
-use rustc_hash::FxHashSet;
 
 use distribution_types::{Dist, DistributionMetadata, LocalEditable};
 use pep508_rs::{MarkerEnvironment, Requirement, VersionOrUrl};
@@ -79,7 +78,6 @@ impl<'a, Context: BuildContext + Send + Sync> LookaheadResolver<'a, Context> {
     pub async fn resolve(self, markers: &MarkerEnvironment) -> Result<Vec<RequestedRequirements>> {
         let mut results = Vec::new();
         let mut futures = FuturesUnordered::new();
-        let mut seen = FxHashSet::default();
 
         // Queue up the initial requirements.
         let mut queue: VecDeque<Requirement> = self
@@ -96,11 +94,8 @@ impl<'a, Context: BuildContext + Send + Sync> LookaheadResolver<'a, Context> {
 
         while !queue.is_empty() || !futures.is_empty() {
             while let Some(requirement) = queue.pop_front() {
-                // Ignore duplicates. If we have conflicting URLs, we'll catch that later.
                 if matches!(requirement.version_or_url, Some(VersionOrUrl::Url(_))) {
-                    if seen.insert(requirement.name.clone()) {
-                        futures.push(self.lookahead(requirement));
-                    }
+                    futures.push(self.lookahead(requirement));
                 }
             }
 

crates/uv-resolver/src/pubgrub/dependencies.rs

@@ -177,7 +177,7 @@ fn to_pubgrub(
                 ));
             };
 
-            if !urls.is_allowed(expected, url) {
+            if !Urls::is_allowed(expected, url) {
                 return Err(ResolveError::ConflictingUrlsTransitive(
                     requirement.name.clone(),
                     expected.verbatim().to_string(),