Use custom incompatibility

crates/uv-client/src/registry_client.rs

@@ -1149,14 +1149,6 @@ impl SimpleMetadata {
                 warn!("Skipping file for {package_name}: {}", file.filename);
                 continue;
             };
-            if filename.name() != package_name {
-                warn!(
-                    "Skipping file with mismatched package name: `{}` vs. `{}`",
-                    filename.name(),
-                    package_name
-                );
-                continue;
-            }
             let file = match File::try_from(file, &base) {
                 Ok(file) => file,
                 Err(err) => {

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

@@ -2,6 +2,7 @@ use std::fmt::{Display, Formatter};
 
 use crate::resolver::{MetadataUnavailable, VersionFork};
 use uv_distribution_types::IncompatibleDist;
+use uv_normalize::PackageName;
 use uv_pep440::{Version, VersionSpecifiers};
 use uv_platform_tags::{AbiTag, Tags};
 
@@ -38,6 +39,8 @@ pub enum UnavailableVersion {
     InconsistentMetadata,
     /// The wheel has an invalid structure.
     InvalidStructure,
+    /// A package with the wrong name is on an index page.
+    PackageNameMismatch { dist_name: PackageName },
     /// The wheel metadata was not found in the cache and the network is not available.
     Offline,
     /// The source distribution has a `requires-python` requirement that is not met by the installed
@@ -52,6 +55,11 @@ impl UnavailableVersion {
             Self::InvalidMetadata => "invalid metadata".into(),
             Self::InconsistentMetadata => "inconsistent metadata".into(),
             Self::InvalidStructure => "an invalid package format".into(),
+            Self::PackageNameMismatch {
+                dist_name: wrong_name,
+            } => {
+                format!("the wrong package name in the index page (`{wrong_name}`)")
+            }
             Self::Offline => "to be downloaded from a registry".into(),
             Self::RequiresPython(requires_python) => {
                 format!("Python {requires_python}")
@@ -65,6 +73,7 @@ impl UnavailableVersion {
             Self::InvalidMetadata => format!("has {self}"),
             Self::InconsistentMetadata => format!("has {self}"),
             Self::InvalidStructure => format!("has {self}"),
+            Self::PackageNameMismatch { .. } => format!("has {self}"),
             Self::Offline => format!("needs {self}"),
             Self::RequiresPython(..) => format!("requires {self}"),
         }
@@ -76,6 +85,7 @@ impl UnavailableVersion {
             Self::InvalidMetadata => format!("have {self}"),
             Self::InconsistentMetadata => format!("have {self}"),
             Self::InvalidStructure => format!("have {self}"),
+            Self::PackageNameMismatch { .. } => format!("have {self}"),
             Self::Offline => format!("need {self}"),
             Self::RequiresPython(..) => format!("require {self}"),
         }
@@ -93,6 +103,7 @@ impl UnavailableVersion {
             Self::InvalidMetadata => None,
             Self::InconsistentMetadata => None,
             Self::InvalidStructure => None,
+            Self::PackageNameMismatch { .. } => None,
             Self::Offline => None,
             Self::RequiresPython(..) => None,
         }

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

@@ -1370,7 +1370,11 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
             candidate.choice_kind(),
             filename,
         );
-        self.visit_candidate(&candidate, dist, package, name, pins, request_sink)?;
+        if let Some(incompatibility) =
+            self.visit_candidate(&candidate, dist, package, name, pins, request_sink)?
+        {
+            return Ok(Some(incompatibility));
+        }
 
         let version = candidate.version().clone();
         Ok(Some(ResolverVersion::Unforked(version)))
@@ -1531,14 +1535,17 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                 base_candidate.choice_kind(),
                 filename,
             );
-            self.visit_candidate(
+
+            if let Some(incompatibility) = self.visit_candidate(
                 &base_candidate,
                 base_dist,
                 package,
                 name,
                 pins,
                 request_sink,
-            )?;
+            )? {
+                return Ok(Some(incompatibility));
+            }
 
             return Ok(Some(ResolverVersion::Unforked(
                 base_candidate.version().clone(),
@@ -1585,15 +1592,21 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                 .collect::<Vec<_>>()
                 .join(", ")
         );
-        self.visit_candidate(candidate, dist, package, name, pins, request_sink)?;
+        if let Some(incompatibility) =
-        self.visit_candidate(
+            self.visit_candidate(candidate, dist, package, name, pins, request_sink)?
+        {
+            return Ok(Some(incompatibility));
+        }
+        if let Some(incompatibility) = self.visit_candidate(
             &base_candidate,
             base_dist,
             package,
             name,
             pins,
             request_sink,
-        )?;
+        )? {
+            return Ok(Some(incompatibility));
+        }
 
         let forks = vec![
             VersionFork {
@@ -1611,6 +1624,8 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
     }
 
     /// Visit a selected candidate.
+    ///
+    /// Returns an unavailability if the version can't be used.
     fn visit_candidate(
         &self,
         candidate: &Candidate,
@@ -1619,7 +1634,18 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
         name: &PackageName,
         pins: &mut FilePins,
         request_sink: &Sender<Request>,
-    ) -> Result<(), ResolveError> {
+    ) -> Result<Option<ResolverVersion>, ResolveError> {
+        // If there is a package with a different name then the index page on the index, return
+        // an unavailability.
+        if dist.name() != (name) {
+            return Ok(Some(ResolverVersion::Unavailable(
+                candidate.version().clone(),
+                UnavailableVersion::PackageNameMismatch {
+                    dist_name: dist.name().clone(),
+                },
+            )));
+        }
+
         // We want to return a package pinned to a specific version; but we _also_ want to
         // store the exact file that we selected to satisfy that version.
         pins.insert(candidate, dist);
@@ -1649,7 +1675,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
             }
         }
 
-        Ok(())
+        Ok(None)
     }
 
     /// Check if the distribution is incompatible with the Python requirement, and if so, return
@@ -2500,6 +2526,18 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                     return Ok(None);
                 }
 
+                // If there is a package with a different name then the index page on the index,
+                // `chose_version` later returns an unavailability. Ignoring it here allows the
+                // resolver to continue instead of erroring from a prefetch.
+                if dist.name() != &package_name {
+                    warn!(
+                        "Expected packages name {} and distribution name {} do not match, skipping prefetch",
+                        dist.name(),
+                        package_name
+                    );
+                    return Ok(None);
+                }
+
                 // Emit a request to fetch the metadata for this version.
                 if self.index.distributions().register(candidate.version_id()) {
                     let dist = dist.for_resolution().to_owned();

crates/uv/tests/it/pip_compile.rs

@@ -17756,3 +17756,84 @@ fn omit_python_patch_universal() -> Result<()> {
 
     Ok(())
 }
+
+/// Test for cases where the index page for a package contains distributions for a different
+/// package.
+#[tokio::test]
+async fn package_name_on_index_package_mismatch() -> Result<()> {
+    let context = TestContext::new("3.12");
+    let server = MockServer::start().await;
+
+    // An index for anyio, with tqdm and anyio distributions.
+    let networkx_page = r#"
+    <!DOCTYPE html>
+    <html>
+        <body>
+        <h1>Links for anyio</h1>
+        <a href="https://files.pythonhosted.org/packages/d0/30/dc54f88dd4a2b5dc8a0279bdd7270e735851848b762aeb1c1184ed1f6b14/tqdm-4.67.1-py3-none-any.whl#sha256=26445eca388f82e72884e0d580d5464cd801a3ea01e63e5601bdff9ba6a48de2" data-requires-python="&gt;=3.7" data-dist-info-metadata="sha256=688a1632df525a198fec52dcfefb1246d31eacee9c035aacac2d7eaf8d8ff669" data-core-metadata="sha256=688a1632df525a198fec52dcfefb1246d31eacee9c035aacac2d7eaf8d8ff669">tqdm-4.67.1-py3-none-any.whl</a><br />
+        <a href="https://files.pythonhosted.org/packages/a8/4b/29b4ef32e036bb34e4ab51796dd745cdba7ed47ad142a9f4a1eb8e0c744d/tqdm-4.67.1.tar.gz#sha256=f8aef9c52c08c13a65f30ea34f4e5aac3fd1a34959879d7e59e63027286627f2" data-requires-python="&gt;=3.7" >tqdm-4.67.1.tar.gz</a><br />
+        <a href="https://files.pythonhosted.org/packages/6f/12/e5e0282d673bb9746bacfb6e2dba8719989d3660cdb2ea79aee9a9651afb/anyio-4.10.0-py3-none-any.whl#sha256=60e474ac86736bbfd6f210f7a61218939c318f43f9972497381f1c5e930ed3d1" data-requires-python="&gt;=3.9" data-dist-info-metadata="sha256=d400ffeb480f82ac562ac3b9e055136ca0d01f29e2e63ff9ebf5d08a7289f4b4" data-core-metadata="sha256=d400ffeb480f82ac562ac3b9e055136ca0d01f29e2e63ff9ebf5d08a7289f4b4">anyio-4.10.0-py3-none-any.whl</a><br />
+        <a href="https://files.pythonhosted.org/packages/f1/b4/636b3b65173d3ce9a38ef5f0522789614e590dab6a8d505340a4efe4c567/anyio-4.10.0.tar.gz#sha256=3f3fae35c96039744587aa5b8371e7e8e603c0702999535961dd336026973ba6" data-requires-python="&gt;=3.9" >anyio-4.10.0.tar.gz</a><br />
+    </body>
+    </html>
+    "#;
+    Mock::given(method("GET"))
+        .and(path("/anyio/"))
+        .respond_with(ResponseTemplate::new(200).set_body_raw(networkx_page, "text/html"))
+        .mount(&server)
+        .await;
+
+    // Skip over the tqdm version, resolve to the older anyio version.
+    let requirements_in = context.temp_dir.child("requirements.in");
+    requirements_in.write_str("anyio")?;
+
+    uv_snapshot!(context
+        .pip_compile()
+        .env_remove(EnvVars::UV_EXCLUDE_NEWER)
+        .arg("--extra-index-url")
+        .arg(server.uri())
+        .arg("requirements.in"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] requirements.in
+    anyio==4.10.0
+        # via -r requirements.in
+    idna==3.10
+        # via anyio
+    sniffio==1.3.1
+        # via anyio
+    typing-extensions==4.15.0
+        # via anyio
+
+    ----- stderr -----
+    Resolved 4 packages in [TIME]
+    ");
+
+    // Error with our custom incompatibility when there are only bogus packages in the version
+    // range.
+    let requirements_in = context.temp_dir.child("requirements.in");
+    requirements_in.write_str("anyio>4.10")?;
+
+    uv_snapshot!(context
+        .pip_compile()
+        .env_remove(EnvVars::UV_EXCLUDE_NEWER)
+        .arg("--extra-index-url")
+        .arg(server.uri())
+        .arg("requirements.in"), @r"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+
+    ----- stderr -----
+      × No solution found when resolving dependencies:
+      ╰─▶ Because only the following versions of anyio are available:
+              anyio<4.10
+              anyio==4.67.1
+          and anyio==4.67.1 has the wrong package name in the index page (`tqdm`), we can conclude that anyio>4.10 cannot be used.
+          And because you require anyio>4.10, we can conclude that your requirements are unsatisfiable.
+    ");
+
+    Ok(())
+}

crates/uv/tests/it/pip_install.rs

@@ -11688,11 +11688,14 @@ async fn bogus_redirect() -> Result<()> {
             .arg("sniffio"),
         @r"
     success: false
-    exit_code: 2
+    exit_code: 1
     ----- stdout -----
 
     ----- stderr -----
-    error: The index returned metadata for the wrong package: expected distribution for sniffio, got distribution for anyio
+      × No solution found when resolving dependencies:
+      ╰─▶ Because all versions of sniffio have the wrong package name in the index page (`anyio`) and you require sniffio, we can conclude that your requirements are unsatisfiable.
+
+          hint: Pre-releases are available for `sniffio` in the requested range (e.g., 4.0.0rc1), but pre-releases weren't enabled (try: `--prerelease=allow`)
     "
     );