Pass around index with associated metadata (#12406)

## Summary

This PR modifies the requirement source entities to store a (new)
container struct that wraps `IndexUrl`. This will allow us to store
user-defined metadata alongside `IndexUrl`, and propagate that metadata
throughout resolution.

Specifically, I need to store the "kind" of the index (Simple API vs.
`--find-links`), but I also ran into this problem when I tried to add
support for overriding `Cache-Control` headers on a per-index basis: at
present, we have no way to passing around metadata alongside an
`IndexUrl`.

crates/uv-auth/src/policy.rs

@@ -3,7 +3,17 @@ use url::Url;
 
 /// When to use authentication.
 #[derive(
-    Copy, Clone, Debug, Default, Hash, Eq, PartialEq, serde::Serialize, serde::Deserialize,
+    Copy,
+    Clone,
+    Debug,
+    Default,
+    Hash,
+    Eq,
+    PartialEq,
+    Ord,
+    PartialOrd,
+    serde::Serialize,
+    serde::Deserialize,
 )]
 #[serde(rename_all = "kebab-case")]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]

crates/uv-client/src/registry_client.rs

@@ -13,14 +13,14 @@ use reqwest_middleware::ClientWithMiddleware;
 use tokio::sync::Semaphore;
 use tracing::{info_span, instrument, trace, warn, Instrument};
 use url::Url;
-use uv_auth::UrlAuthPolicies;
 
+use uv_auth::UrlAuthPolicies;
 use uv_cache::{Cache, CacheBucket, CacheEntry, WheelCache};
 use uv_configuration::KeyringProviderType;
 use uv_configuration::{IndexStrategy, TrustedHost};
 use uv_distribution_filename::{DistFilename, SourceDistFilename, WheelFilename};
 use uv_distribution_types::{
-    BuiltDist, File, FileLocation, Index, IndexCapabilities, IndexUrl, IndexUrls, Name,
+    BuiltDist, File, FileLocation, IndexCapabilities, IndexMetadataRef, IndexUrl, IndexUrls, Name,
 };
 use uv_metadata::{read_metadata_async_seek, read_metadata_async_stream};
 use uv_normalize::PackageName;
@@ -255,16 +255,17 @@ impl RegistryClient {
     }
 
     /// Return the appropriate index URLs for the given [`PackageName`].
-    fn index_urls_for(&self, package_name: &PackageName) -> impl Iterator<Item = &IndexUrl> {
+    fn index_urls_for(&self, package_name: &PackageName) -> impl Iterator<Item = IndexMetadataRef> {
         self.torch_backend
             .as_ref()
             .and_then(|torch_backend| {
                 torch_backend
                     .applies_to(package_name)
                     .then(|| torch_backend.index_urls())
+                    .map(|indexes| indexes.map(IndexMetadataRef::from))
             })
             .map(Either::Left)
-            .unwrap_or_else(|| Either::Right(self.index_urls.indexes().map(Index::url)))
+            .unwrap_or_else(|| Either::Right(self.index_urls.indexes().map(IndexMetadataRef::from)))
     }
 
     /// Return the appropriate [`IndexStrategy`] for the given [`PackageName`].
@@ -288,10 +289,10 @@ impl RegistryClient {
     pub async fn simple<'index>(
         &'index self,
         package_name: &PackageName,
-        index: Option<&'index IndexUrl>,
+        index: Option<IndexMetadataRef<'index>>,
         capabilities: &IndexCapabilities,
         download_concurrency: &Semaphore,
-    ) -> Result<Vec<(&'index IndexUrl, OwnedArchive<SimpleMetadata>)>, Error> {
+    ) -> Result<Vec<(IndexMetadataRef<'index>, OwnedArchive<SimpleMetadata>)>, Error> {
         // If `--no-index` is specified, avoid fetching regardless of whether the index is implicit,
         // explicit, etc.
         if self.index_urls.no_index() {
@@ -312,7 +313,7 @@ impl RegistryClient {
                 for index in indexes {
                     let _permit = download_concurrency.acquire().await;
                     if let Some(metadata) = self
-                        .simple_single_index(package_name, index, capabilities)
+                        .simple_single_index(package_name, index.url(), capabilities)
                         .await?
                     {
                         results.push((index, metadata));
@@ -327,7 +328,7 @@ impl RegistryClient {
                     .map(|index| async move {
                         let _permit = download_concurrency.acquire().await;
                         let metadata = self
-                            .simple_single_index(package_name, index, capabilities)
+                            .simple_single_index(package_name, index.url(), capabilities)
                             .await?;
                         Ok((index, metadata))
                     })
@@ -369,9 +370,9 @@ impl RegistryClient {
         capabilities: &IndexCapabilities,
     ) -> Result<Option<OwnedArchive<SimpleMetadata>>, Error> {
         // Format the URL for PyPI.
-        let mut url: Url = index.clone().into();
+        let mut url = index.url().clone();
         url.path_segments_mut()
-            .map_err(|()| ErrorKind::CannotBeABase(index.clone().into()))?
+            .map_err(|()| ErrorKind::CannotBeABase(index.url().clone()))?
             .pop_if_empty()
             .push(package_name.as_ref())
             // The URL *must* end in a trailing slash for proper relative path behavior

crates/uv-distribution-types/src/index.rs

@@ -10,7 +10,9 @@ use crate::index_name::{IndexName, IndexNameError};
 use crate::origin::Origin;
 use crate::{IndexUrl, IndexUrlError};
 
-#[derive(Debug, Clone, Hash, Eq, PartialEq, serde::Serialize, serde::Deserialize)]
+#[derive(
+    Debug, Clone, Hash, Eq, PartialEq, Ord, PartialOrd, serde::Serialize, serde::Deserialize,
+)]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
 #[serde(rename_all = "kebab-case")]
 pub struct Index {
@@ -200,6 +202,20 @@ impl Index {
     }
 }
 
+impl From<IndexUrl> for Index {
+    fn from(value: IndexUrl) -> Self {
+        Self {
+            name: None,
+            url: value,
+            explicit: false,
+            default: false,
+            origin: None,
+            publish_url: None,
+            authenticate: AuthPolicy::default(),
+        }
+    }
+}
+
 impl FromStr for Index {
     type Err = IndexSourceError;
 
@@ -235,6 +251,76 @@ impl FromStr for Index {
     }
 }
 
+/// An [`IndexUrl`] along with the metadata necessary to query the index.
+#[derive(Debug, Clone, Hash, Eq, PartialEq, Ord, PartialOrd)]
+pub struct IndexMetadata {
+    pub url: IndexUrl,
+    // /// The type of the index.
+    // ///
+    // /// Indexes can either be PEP 503-compliant (i.e., a registry implementing the Simple API) or
+    // /// structured as a flat list of distributions (e.g., `--find-links`). In both cases, indexes
+    // /// can point to either local or remote resources.
+    // #[serde(default)]
+    // pub r#type: IndexKind,
+}
+
+impl IndexMetadata {
+    /// Return a reference to the [`IndexMetadata`].
+    pub fn as_ref(&self) -> IndexMetadataRef<'_> {
+        let Self { url } = self;
+        IndexMetadataRef { url }
+    }
+
+    /// Consume the [`IndexMetadata`] and return the [`IndexUrl`].
+    pub fn into_url(self) -> IndexUrl {
+        self.url
+    }
+}
+
+/// A reference to an [`IndexMetadata`].
+#[derive(Debug, Copy, Clone)]
+pub struct IndexMetadataRef<'a> {
+    pub url: &'a IndexUrl,
+}
+
+impl IndexMetadata {
+    /// Return the [`IndexUrl`] of the index.
+    pub fn url(&self) -> &IndexUrl {
+        &self.url
+    }
+}
+
+impl IndexMetadataRef<'_> {
+    /// Return the [`IndexUrl`] of the index.
+    pub fn url(&self) -> &IndexUrl {
+        self.url
+    }
+}
+
+impl<'a> From<&'a IndexMetadata> for IndexMetadataRef<'a> {
+    fn from(value: &'a IndexMetadata) -> Self {
+        Self { url: &value.url }
+    }
+}
+
+impl<'a> From<&'a IndexUrl> for IndexMetadataRef<'a> {
+    fn from(value: &'a IndexUrl) -> Self {
+        Self { url: value }
+    }
+}
+
+impl<'a> From<&'a Index> for IndexMetadataRef<'a> {
+    fn from(value: &'a Index) -> Self {
+        Self { url: &value.url }
+    }
+}
+
+impl From<IndexUrl> for IndexMetadata {
+    fn from(value: IndexUrl) -> Self {
+        Self { url: value }
+    }
+}
+
 /// An error that can occur when parsing an [`Index`].
 #[derive(Error, Debug)]
 pub enum IndexSourceError {

crates/uv-distribution-types/src/index_name.rs

@@ -9,7 +9,7 @@ use uv_small_str::SmallString;
 /// The normalized name of an index.
 ///
 /// Index names may contain letters, digits, hyphens, underscores, and periods, and must be ASCII.
-#[derive(Debug, Clone, Hash, Eq, PartialEq, serde::Serialize)]
+#[derive(Debug, Clone, Hash, Eq, PartialEq, Ord, PartialOrd, serde::Serialize)]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
 pub struct IndexName(SmallString);
 

crates/uv-distribution-types/src/origin.rs

@@ -1,5 +1,5 @@
 /// The origin of a piece of configuration.
-#[derive(Debug, Copy, Clone, Hash, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, Hash, Eq, PartialEq, Ord, PartialOrd)]
 pub enum Origin {
     /// The setting was provided via the CLI.
     Cli,

crates/uv-distribution-types/src/requirement.rs

@@ -14,6 +14,9 @@ use uv_pep440::VersionSpecifiers;
 use uv_pep508::{
     marker, MarkerEnvironment, MarkerTree, RequirementOrigin, VerbatimUrl, VersionOrUrl,
 };
+
+use crate::{IndexMetadata, IndexUrl};
+
 use uv_pypi_types::{
     ConflictItem, Hashes, ParsedArchiveUrl, ParsedDirectoryUrl, ParsedGitUrl, ParsedPathUrl,
     ParsedUrl, ParsedUrlError, VerbatimParsedUrl,
@@ -320,7 +323,7 @@ impl Display for Requirement {
             } => {
                 write!(f, "{specifier}")?;
                 if let Some(index) = index {
-                    write!(f, " (index: {index})")?;
+                    write!(f, " (index: {})", index.url)?;
                 }
             }
             RequirementSource::Url { url, .. } => {
@@ -368,7 +371,7 @@ pub enum RequirementSource {
     Registry {
         specifier: VersionSpecifiers,
         /// Choose a version from the index at the given URL.
-        index: Option<Url>,
+        index: Option<IndexMetadata>,
         /// The conflict item associated with the source, if any.
         conflict: Option<ConflictItem>,
     },
@@ -600,7 +603,7 @@ impl Display for RequirementSource {
             } => {
                 write!(f, "{specifier}")?;
                 if let Some(index) = index {
-                    write!(f, " (index: {index})")?;
+                    write!(f, " (index: {})", index.url)?;
                 }
             }
             Self::Url { url, .. } => {
@@ -662,12 +665,13 @@ impl From<RequirementSource> for RequirementSourceWire {
         match value {
             RequirementSource::Registry {
                 specifier,
-                mut index,
+                index,
                 conflict,
             } => {
-                if let Some(index) = index.as_mut() {
+                let index = index.map(|index| index.url.into_url()).map(|mut index| {
-                    redact_credentials(index);
+                    redact_credentials(&mut index);
-                }
+                    index
+                });
                 Self::Registry {
                     specifier,
                     index,
@@ -775,7 +779,8 @@ impl TryFrom<RequirementSourceWire> for RequirementSource {
                 conflict,
             } => Ok(Self::Registry {
                 specifier,
-                index,
+                index: index
+                    .map(|index| IndexMetadata::from(IndexUrl::from(VerbatimUrl::from_url(index)))),
                 conflict,
             }),
             RequirementSourceWire::Git { git } => {

crates/uv-distribution-types/src/resolution.rs

@@ -3,7 +3,9 @@ use uv_normalize::{ExtraName, GroupName, PackageName};
 use uv_pep508::MarkerTree;
 use uv_pypi_types::{HashDigest, HashDigests};
 
-use crate::{BuiltDist, Diagnostic, Dist, Name, RequirementSource, ResolvedDist, SourceDist};
+use crate::{
+    BuiltDist, Diagnostic, Dist, IndexMetadata, Name, RequirementSource, ResolvedDist, SourceDist,
+};
 
 /// A set of packages pinned at specific versions.
 ///
@@ -229,7 +231,7 @@ impl From<&ResolvedDist> for RequirementSource {
                                 wheel.filename.version.clone(),
                             ),
                         ),
-                        index: Some(wheel.index.url().clone()),
+                        index: Some(IndexMetadata::from(wheel.index.clone())),
                         conflict: None,
                     }
                 }
@@ -252,7 +254,7 @@ impl From<&ResolvedDist> for RequirementSource {
                     specifier: uv_pep440::VersionSpecifiers::from(
                         uv_pep440::VersionSpecifier::equals_version(sdist.version.clone()),
                     ),
-                    index: Some(sdist.index.url().clone()),
+                    index: Some(IndexMetadata::from(sdist.index.clone())),
                     conflict: None,
                 },
                 Dist::Source(SourceDist::DirectUrl(sdist)) => {

crates/uv-distribution/src/metadata/lowering.rs

@@ -8,7 +8,7 @@ use url::Url;
 
 use uv_distribution_filename::DistExtension;
 use uv_distribution_types::{
-    Index, IndexLocations, IndexName, Origin, Requirement, RequirementSource,
+    Index, IndexLocations, IndexMetadata, IndexName, Origin, Requirement, RequirementSource,
 };
 use uv_git_types::{GitReference, GitUrl, GitUrlParseError};
 use uv_normalize::{ExtraName, GroupName, PackageName};
@@ -222,7 +222,9 @@ impl LoweredRequirement {
                                 .find(|Index { name, .. }| {
                                     name.as_ref().is_some_and(|name| *name == index)
                                 })
-                                .map(|Index { url: index, .. }| index.clone())
+                                .map(|index| IndexMetadata {
+                                    url: index.url.clone(),
+                                })
                             else {
                                 return Err(LoweringError::MissingIndex(
                                     requirement.name.clone(),
@@ -238,7 +240,7 @@ impl LoweredRequirement {
                                     })
                                 }
                             });
-                            let source = registry_source(&requirement, index.into_url(), conflict);
+                            let source = registry_source(&requirement, index, conflict);
                             (source, marker)
                         }
                         Source::Workspace {
@@ -445,7 +447,9 @@ impl LoweredRequirement {
                                 .find(|Index { name, .. }| {
                                     name.as_ref().is_some_and(|name| *name == index)
                                 })
-                                .map(|Index { url: index, .. }| index.clone())
+                                .map(|index| IndexMetadata {
+                                    url: index.url.clone(),
+                                })
                             else {
                                 return Err(LoweringError::MissingIndex(
                                     requirement.name.clone(),
@@ -453,7 +457,7 @@ impl LoweredRequirement {
                                 ));
                             };
                             let conflict = None;
-                            let source = registry_source(&requirement, index.into_url(), conflict);
+                            let source = registry_source(&requirement, index, conflict);
                             (source, marker)
                         }
                         Source::Workspace { .. } => {
@@ -627,7 +631,7 @@ fn url_source(
 /// Convert a registry source into a [`RequirementSource`].
 fn registry_source(
     requirement: &uv_pep508::Requirement<VerbatimParsedUrl>,
-    index: Url,
+    index: IndexMetadata,
     conflict: Option<ConflictItem>,
 ) -> RequirementSource {
     match &requirement.version_or_url {

crates/uv-publish/src/lib.rs

@@ -479,7 +479,7 @@ pub async fn check_url(
     let response = match registry_client
         .simple(
             filename.name(),
-            Some(index_url),
+            Some(index_url.into()),
             index_capabilities,
             download_concurrency,
         )

crates/uv-resolver/src/fork_indexes.rs

@@ -1,5 +1,5 @@
 use rustc_hash::FxHashMap;
-use uv_distribution_types::IndexUrl;
+use uv_distribution_types::IndexMetadata;
 use uv_normalize::PackageName;
 
 use crate::resolver::ResolverEnvironment;
@@ -7,24 +7,24 @@ use crate::ResolveError;
 
 /// See [`crate::resolver::ForkState`].
 #[derive(Default, Debug, Clone)]
-pub(crate) struct ForkIndexes(FxHashMap<PackageName, IndexUrl>);
+pub(crate) struct ForkIndexes(FxHashMap<PackageName, IndexMetadata>);
 
 impl ForkIndexes {
-    /// Get the [`IndexUrl`] previously used for a package in this fork.
+    /// Get the [`Index`] previously used for a package in this fork.
-    pub(crate) fn get(&self, package_name: &PackageName) -> Option<&IndexUrl> {
+    pub(crate) fn get(&self, package_name: &PackageName) -> Option<&IndexMetadata> {
         self.0.get(package_name)
     }
 
-    /// Check that this is the only [`IndexUrl`] used for this package in this fork.
+    /// Check that this is the only [`Index`] used for this package in this fork.
     pub(crate) fn insert(
         &mut self,
         package_name: &PackageName,
-        index: &IndexUrl,
+        index: &IndexMetadata,
         env: &ResolverEnvironment,
     ) -> Result<(), ResolveError> {
         if let Some(previous) = self.0.insert(package_name.clone(), index.clone()) {
             if &previous != index {
-                let mut conflicts = vec![previous.to_string(), index.to_string()];
+                let mut conflicts = vec![previous.url.to_string(), index.url.to_string()];
                 conflicts.sort();
                 return Err(ResolveError::ConflictingIndexesForEnvironment {
                     package_name: package_name.clone(),

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

@@ -27,9 +27,9 @@ use uv_distribution_filename::{
 use uv_distribution_types::{
     redact_credentials, BuiltDist, DependencyMetadata, DirectUrlBuiltDist, DirectUrlSourceDist,
     DirectorySourceDist, Dist, DistributionMetadata, FileLocation, GitSourceDist, IndexLocations,
-    IndexUrl, Name, PathBuiltDist, PathSourceDist, RegistryBuiltDist, RegistryBuiltWheel,
+    IndexMetadata, IndexUrl, Name, PathBuiltDist, PathSourceDist, RegistryBuiltDist,
-    RegistrySourceDist, RemoteSource, Requirement, RequirementSource, ResolvedDist, StaticMetadata,
+    RegistryBuiltWheel, RegistrySourceDist, RemoteSource, Requirement, RequirementSource,
-    ToUrlError, UrlString,
+    ResolvedDist, StaticMetadata, ToUrlError, UrlString,
 };
 use uv_fs::{relative_to, PortablePath, PortablePathBuf};
 use uv_git::{RepositoryReference, ResolvedRepositoryReference};
@@ -4563,12 +4563,17 @@ fn normalize_requirement(
         }
         RequirementSource::Registry {
             specifier,
-            mut index,
+            index,
             conflict,
         } => {
-            if let Some(index) = index.as_mut() {
+            // Round-trip the index to remove anything apart from the URL.
-                redact_credentials(index);
+            let index = index
-            }
+                .map(|index| index.url.into_url())
+                .map(|mut index| {
+                    redact_credentials(&mut index);
+                    index
+                })
+                .map(|index| IndexMetadata::from(IndexUrl::from(VerbatimUrl::from_url(index))));
             Ok(Requirement {
                 name: requirement.name,
                 extras: requirement.extras,

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

@@ -11,7 +11,7 @@ use rustc_hash::FxHashMap;
 use uv_configuration::{IndexStrategy, NoBinary, NoBuild};
 use uv_distribution_types::{
     IncompatibleDist, IncompatibleSource, IncompatibleWheel, Index, IndexCapabilities,
-    IndexLocations, IndexUrl,
+    IndexLocations, IndexMetadata, IndexUrl,
 };
 use uv_normalize::PackageName;
 use uv_pep440::{Version, VersionSpecifiers};
@@ -727,7 +727,7 @@ impl PubGrubReportFormatter<'_> {
         env: &ResolverEnvironment,
         tags: Option<&Tags>,
     ) -> Option<PubGrubHint> {
-        let response = if let Some(url) = fork_indexes.get(name) {
+        let response = if let Some(url) = fork_indexes.get(name).map(IndexMetadata::url) {
             index.explicit().get(&(name.clone(), url.clone()))
         } else {
             index.implicit().get(name)

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

@@ -13,7 +13,9 @@ use crate::resolver::Request;
 use crate::{
     InMemoryIndex, PythonRequirement, ResolveError, ResolverEnvironment, VersionsResponse,
 };
-use uv_distribution_types::{CompatibleDist, DistributionMetadata, IndexCapabilities, IndexUrl};
+use uv_distribution_types::{
+    CompatibleDist, DistributionMetadata, IndexCapabilities, IndexMetadata,
+};
 use uv_normalize::PackageName;
 use uv_pep440::Version;
 use uv_pep508::MarkerTree;
@@ -81,7 +83,7 @@ impl BatchPrefetcher {
     pub(crate) fn prefetch_batches(
         &mut self,
         next: &PubGrubPackage,
-        index: Option<&IndexUrl>,
+        index: Option<&IndexMetadata>,
         version: &Version,
         current_range: &Range<Version>,
         unchangeable_constraints: Option<&Term<Range<Version>>>,
@@ -110,7 +112,7 @@ impl BatchPrefetcher {
             self.prefetch_runner
                 .index
                 .explicit()
-                .wait_blocking(&(name.clone(), index.clone()))
+                .wait_blocking(&(name.clone(), index.url().clone()))
                 .ok_or_else(|| ResolveError::UnregisteredTask(name.to_string()))?
         } else {
             self.prefetch_runner

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

@@ -1,6 +1,5 @@
-use uv_distribution_types::{IndexUrl, RequirementSource};
+use uv_distribution_types::{IndexMetadata, RequirementSource};
 use uv_normalize::PackageName;
-use uv_pep508::VerbatimUrl;
 use uv_pypi_types::ConflictItem;
 
 use crate::resolver::ForkMap;
@@ -24,7 +23,7 @@ pub(crate) struct Indexes(ForkMap<Entry>);
 
 #[derive(Debug, Clone)]
 struct Entry {
-    index: IndexUrl,
+    index: IndexMetadata,
     conflict: Option<ConflictItem>,
 }
 
@@ -46,7 +45,9 @@ impl Indexes {
             else {
                 continue;
             };
-            let index = IndexUrl::from(VerbatimUrl::from_url(index.clone()));
+            let index = IndexMetadata {
+                url: index.url.clone(),
+            };
             let conflict = conflict.clone();
             indexes.add(&requirement, Entry { index, conflict });
         }
@@ -60,7 +61,7 @@ impl Indexes {
     }
 
     /// Return the explicit index used for a package in the given fork.
-    pub(crate) fn get(&self, name: &PackageName, env: &ResolverEnvironment) -> Vec<&IndexUrl> {
+    pub(crate) fn get(&self, name: &PackageName, env: &ResolverEnvironment) -> Vec<&IndexMetadata> {
         let entries = self.0.get(name, env);
         entries
             .iter()

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

@@ -25,8 +25,8 @@ use uv_distribution::DistributionDatabase;
 use uv_distribution_types::{
     BuiltDist, CompatibleDist, DerivationChain, Dist, DistErrorKind, DistributionMetadata,
     IncompatibleDist, IncompatibleSource, IncompatibleWheel, IndexCapabilities, IndexLocations,
-    IndexUrl, InstalledDist, PythonRequirementKind, RemoteSource, Requirement, ResolvedDist,
+    IndexMetadata, IndexUrl, InstalledDist, PythonRequirementKind, RemoteSource, Requirement,
-    ResolvedDistRef, SourceDist, VersionOrUrlRef,
+    ResolvedDist, ResolvedDistRef, SourceDist, VersionOrUrlRef,
 };
 use uv_git::GitResolver;
 use uv_normalize::{ExtraName, GroupName, PackageName};
@@ -494,7 +494,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                     let decision = self.choose_version(
                         next_package,
                         next_id,
-                        index,
+                        index.map(IndexMetadata::url),
                         term_intersection.unwrap_positive(),
                         &mut state.pins,
                         &preferences,
@@ -925,7 +925,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
         &self,
         package: &PubGrubPackage,
         url: Option<&VerbatimParsedUrl>,
-        index: Option<&IndexUrl>,
+        index: Option<&IndexMetadata>,
         request_sink: &Sender<Request>,
     ) -> Result<(), ResolveError> {
         // Ignore unresolved URL packages, i.e., packages that use a direct URL in some forks.
@@ -945,7 +945,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
         &self,
         package: &PubGrubPackage,
         url: Option<&VerbatimParsedUrl>,
-        index: Option<&IndexUrl>,
+        index: Option<&IndexMetadata>,
         request_sink: &Sender<Request>,
     ) -> Result<(), ResolveError> {
         // Only request real packages.
@@ -969,7 +969,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
             if self
                 .index
                 .explicit()
-                .register((name.clone(), index.clone()))
+                .register((name.clone(), index.url().clone()))
             {
                 request_sink.blocking_send(Request::Package(name.clone(), Some(index.clone())))?;
             }
@@ -2249,7 +2249,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
 
                 Ok(Some(Response::Package(
                     package_name,
-                    index,
+                    index.map(IndexMetadata::into_url),
                     package_versions,
                 )))
             }
@@ -2449,7 +2449,9 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                 continue;
             }
             let versions_response = if let Some(index) = fork_indexes.get(name) {
-                self.index.explicit().get(&(name.clone(), index.clone()))
+                self.index
+                    .explicit()
+                    .get(&(name.clone(), index.url().clone()))
             } else {
                 self.index.implicit().get(name)
             };
@@ -3166,7 +3168,7 @@ impl ResolutionDependencyEdge {
 #[allow(clippy::large_enum_variant)]
 pub(crate) enum Request {
     /// A request to fetch the metadata for a package.
-    Package(PackageName, Option<IndexUrl>),
+    Package(PackageName, Option<IndexMetadata>),
     /// A request to fetch the metadata for a built or source distribution.
     Dist(Dist),
     /// A request to fetch the metadata from an already-installed distribution.

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

@@ -3,7 +3,9 @@ use std::sync::Arc;
 
 use uv_configuration::BuildOptions;
 use uv_distribution::{ArchiveMetadata, DistributionDatabase, Reporter};
-use uv_distribution_types::{Dist, IndexCapabilities, IndexUrl, InstalledDist, RequestedDist};
+use uv_distribution_types::{
+    Dist, IndexCapabilities, IndexMetadata, IndexMetadataRef, InstalledDist, RequestedDist,
+};
 use uv_normalize::PackageName;
 use uv_pep440::{Version, VersionSpecifiers};
 use uv_platform_tags::Tags;
@@ -78,7 +80,7 @@ pub trait ResolverProvider {
     fn get_package_versions<'io>(
         &'io self,
         package_name: &'io PackageName,
-        index: Option<&'io IndexUrl>,
+        index: Option<&'io IndexMetadata>,
     ) -> impl Future<Output = PackageVersionsResult> + 'io;
 
     /// Get the metadata for a distribution.
@@ -150,13 +152,18 @@ impl<Context: BuildContext> ResolverProvider for DefaultResolverProvider<'_, Con
     async fn get_package_versions<'io>(
         &'io self,
         package_name: &'io PackageName,
-        index: Option<&'io IndexUrl>,
+        index: Option<&'io IndexMetadata>,
     ) -> PackageVersionsResult {
         let result = self
             .fetcher
             .client()
             .manual(|client, semaphore| {
-                client.simple(package_name, index, self.capabilities, semaphore)
+                client.simple(
+                    package_name,
+                    index.map(IndexMetadataRef::from),
+                    self.capabilities,
+                    semaphore,
+                )
             })
             .await;
 
@@ -171,7 +178,7 @@ impl<Context: BuildContext> ResolverProvider for DefaultResolverProvider<'_, Con
                         VersionMap::from_metadata(
                             metadata,
                             package_name,
-                            index,
+                            index.url(),
                             self.tags.as_ref(),
                             &self.requires_python,
                             &self.allowed_yanks,

crates/uv/src/commands/pip/latest.rs

@@ -2,7 +2,7 @@ use tokio::sync::Semaphore;
 use tracing::debug;
 use uv_client::{RegistryClient, VersionFiles};
 use uv_distribution_filename::DistFilename;
-use uv_distribution_types::{IndexCapabilities, IndexUrl};
+use uv_distribution_types::{IndexCapabilities, IndexMetadataRef, IndexUrl};
 use uv_normalize::PackageName;
 use uv_platform_tags::Tags;
 use uv_resolver::{ExcludeNewer, PrereleaseMode, RequiresPython};
@@ -34,7 +34,12 @@ impl LatestClient<'_> {
 
         let archives = match self
             .client
-            .simple(package, index, self.capabilities, download_concurrency)
+            .simple(
+                package,
+                index.map(IndexMetadataRef::from),
+                self.capabilities,
+                download_concurrency,
+            )
             .await
         {
             Ok(archives) => archives,

crates/uv/src/commands/publish.rs

@@ -1,17 +1,15 @@
-use crate::commands::reporters::PublishReporter;
-use crate::commands::{human_readable_bytes, ExitStatus};
-use crate::printer::Printer;
-use crate::settings::NetworkSettings;
-use anyhow::{bail, Context, Result};
-use console::Term;
-use owo_colors::OwoColorize;
 use std::fmt::Write;
 use std::iter;
 use std::sync::Arc;
 use std::time::Duration;
+
+use anyhow::{bail, Context, Result};
+use console::Term;
+use owo_colors::OwoColorize;
 use tokio::sync::Semaphore;
 use tracing::{debug, info};
 use url::Url;
+
 use uv_cache::Cache;
 use uv_client::{AuthIntegration, BaseClient, BaseClientBuilder, RegistryClientBuilder};
 use uv_configuration::{KeyringProviderType, TrustedPublishing};
@@ -21,6 +19,11 @@ use uv_publish::{
 };
 use uv_warnings::warn_user_once;
 
+use crate::commands::reporters::PublishReporter;
+use crate::commands::{human_readable_bytes, ExitStatus};
+use crate::printer::Printer;
+use crate::settings::NetworkSettings;
+
 pub(crate) async fn publish(
     paths: Vec<String>,
     publish_url: Url,

crates/uv/tests/it/lock.rs

@@ -15331,7 +15331,7 @@ fn lock_explicit_default_index() -> Result<()> {
     DEBUG No workspace root found, using project root
     DEBUG Ignoring existing lockfile due to mismatched requirements for: `project==0.1.0`
       Requested: {Requirement { name: PackageName("anyio"), extras: [], groups: [], marker: true, source: Registry { specifier: VersionSpecifiers([]), index: None, conflict: None }, origin: None }}
-      Existing: {Requirement { name: PackageName("iniconfig"), extras: [], groups: [], marker: true, source: Registry { specifier: VersionSpecifiers([VersionSpecifier { operator: Equal, version: "2.0.0" }]), index: Some(Url { scheme: "https", cannot_be_a_base: false, username: "", password: None, host: Some(Domain("test.pypi.org")), port: None, path: "/simple", query: None, fragment: None }), conflict: None }, origin: None }}
+      Existing: {Requirement { name: PackageName("iniconfig"), extras: [], groups: [], marker: true, source: Registry { specifier: VersionSpecifiers([VersionSpecifier { operator: Equal, version: "2.0.0" }]), index: Some(IndexMetadata { url: Url(VerbatimUrl { url: Url { scheme: "https", cannot_be_a_base: false, username: "", password: None, host: Some(Domain("test.pypi.org")), port: None, path: "/simple", query: None, fragment: None }, given: None }) }), conflict: None }, origin: None }}
     DEBUG Solving with installed Python version: 3.12.[X]
     DEBUG Solving with target Python version: >=3.12
     DEBUG Adding direct dependency: project*