Avoid batch prefetching for un-optimized registries (#7226)

## Summary

We now track the discovered `IndexCapabilities` for each `IndexUrl`. If
we learn that an index doesn't support range requests, we avoid doing
any batch prefetching.

Closes https://github.com/astral-sh/uv/issues/7221.

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

@@ -6,7 +6,7 @@ use rustc_hash::FxHashMap;
 use tokio::sync::mpsc::Sender;
 use tracing::{debug, trace};
 
-use distribution_types::{CompatibleDist, DistributionMetadata};
+use distribution_types::{CompatibleDist, DistributionMetadata, IndexCapabilities};
 use pep440_rs::Version;
 
 use crate::candidate_selector::CandidateSelector;
@@ -52,6 +52,7 @@ impl BatchPrefetcher {
         python_requirement: &PythonRequirement,
         request_sink: &Sender<Request>,
         index: &InMemoryIndex,
+        capabilities: &IndexCapabilities,
         selector: &CandidateSelector,
         markers: &ResolverMarkers,
     ) -> anyhow::Result<(), ResolveError> {
@@ -135,8 +136,17 @@ impl BatchPrefetcher {
             };
 
             // Avoid prefetching source distributions, which could be expensive.
-            if !dist.prefetchable() {
+            let Some(wheel) = dist.wheel() else {
                 continue;
+            };
+
+            // Avoid prefetching built distributions that don't support _either_ PEP 658 (`.metadata`)
+            // or range requests.
+            if !(wheel.file.dist_info_metadata
+                || capabilities.supports_range_requests(&wheel.index))
+            {
+                debug!("Abandoning prefetch for {wheel} due to missing registry capabilities");
+                return Ok(());
             }
 
             // Avoid prefetching for distributions that don't satisfy the Python requirement.

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

@@ -22,8 +22,8 @@ use tracing::{debug, info, instrument, trace, warn, Level};
 
 use distribution_types::{
     BuiltDist, CompatibleDist, Dist, DistributionMetadata, IncompatibleDist, IncompatibleSource,
-    IncompatibleWheel, IndexLocations, InstalledDist, PythonRequirementKind, RemoteSource,
-    ResolvedDist, ResolvedDistRef, SourceDist, VersionOrUrlRef,
+    IncompatibleWheel, IndexCapabilities, IndexLocations, InstalledDist, PythonRequirementKind,
+    RemoteSource, ResolvedDist, ResolvedDistRef, SourceDist, VersionOrUrlRef,
 };
 pub(crate) use fork_map::{ForkMap, ForkSet};
 use locals::Locals;
@@ -95,6 +95,7 @@ struct ResolverState<InstalledPackages: InstalledPackagesProvider> {
     groups: Groups,
     preferences: Preferences,
     git: GitResolver,
+    capabilities: IndexCapabilities,
     exclusions: Exclusions,
     urls: Urls,
     locals: Locals,
@@ -169,6 +170,7 @@ impl<'a, Context: BuildContext, InstalledPackages: InstalledPackagesProvider>
             python_requirement,
             index,
             build_context.git(),
+            build_context.capabilities(),
             provider,
             installed_packages,
         )
@@ -187,12 +189,14 @@ impl<Provider: ResolverProvider, InstalledPackages: InstalledPackagesProvider>
         python_requirement: &PythonRequirement,
         index: &InMemoryIndex,
         git: &GitResolver,
+        capabilities: &IndexCapabilities,
         provider: Provider,
         installed_packages: InstalledPackages,
     ) -> Result<Self, ResolveError> {
         let state = ResolverState {
             index: index.clone(),
             git: git.clone(),
+            capabilities: capabilities.clone(),
             selector: CandidateSelector::for_resolution(options, &manifest, &markers),
             dependency_mode: options.dependency_mode,
             urls: Urls::from_manifest(&manifest, &markers, git, options.dependency_mode)?,
@@ -458,6 +462,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                         &state.python_requirement,
                         &request_sink,
                         &self.index,
+                        &self.capabilities,
                         &self.selector,
                         &state.markers,
                     )?;
@@ -1808,7 +1813,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                 // Avoid prefetching source distributions with unbounded lower-bound ranges. This
                 // often leads to failed attempts to build legacy versions of packages that are
                 // incompatible with modern build tools.
-                if !dist.prefetchable() {
+                if dist.wheel().is_some() {
                     if !self.selector.use_highest_version(&package_name) {
                         if let Some((lower, _)) = range.iter().next() {
                             if lower == &Bound::Unbounded {

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

@@ -61,6 +61,7 @@ pub trait ResolverProvider {
         dist: &'io Dist,
     ) -> impl Future<Output = WheelMetadataResult> + 'io;
 
+    /// Returns the [`IndexLocations`] used by this resolver.
     fn index_locations(&self) -> &IndexLocations;
 
     /// Set the [`uv_distribution::Reporter`] to use for this installer.