Skip metadata fetch for --no-deps and pip sync (#7127)

## Summary

I think a better tradeoff here is to skip fetching metadata, even though
we can't validate the extras.

It will help with situations like
#5073 (comment) in
which, otherwise, we have to download the wheels twice.

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

@@ -1459,6 +1459,8 @@ impl Package {
         } else {
             annotated_dist
                 .metadata
+                .as_ref()
+                .expect("metadata is present")
                 .requires_dist
                 .iter()
                 .cloned()
@@ -1471,6 +1473,8 @@ impl Package {
         } else {
             annotated_dist
                 .metadata
+                .as_ref()
+                .expect("metadata is present")
                 .dev_dependencies
                 .iter()
                 .map(|(group, requirements)| {
@@ -2168,8 +2172,8 @@ impl PackageId {
         annotated_dist: &AnnotatedDist,
         root: &Path,
     ) -> Result<PackageId, LockError> {
-        let name = annotated_dist.metadata.name.clone();
-        let version = annotated_dist.metadata.version.clone();
+        let name = annotated_dist.name.clone();
+        let version = annotated_dist.version.clone();
         let source = Source::from_resolved_dist(&annotated_dist.dist, root)?;
         Ok(Self {
             name,

crates/uv-resolver/src/resolution/graph.rs

@@ -300,29 +300,32 @@ impl ResolutionGraph {
             git,
         )?;
 
-        // Validate the extra.
-        if let Some(extra) = extra {
-            if !metadata.provides_extras.contains(extra) {
-                diagnostics.push(ResolutionDiagnostic::MissingExtra {
-                    dist: dist.clone(),
-                    extra: extra.clone(),
-                });
+        if let Some(metadata) = metadata.as_ref() {
+            // Validate the extra.
+            if let Some(extra) = extra {
+                if !metadata.provides_extras.contains(extra) {
+                    diagnostics.push(ResolutionDiagnostic::MissingExtra {
+                        dist: dist.clone(),
+                        extra: extra.clone(),
+                    });
+                }
             }
-        }
 
-        // Validate the development dependency group.
-        if let Some(dev) = dev {
-            if !metadata.dev_dependencies.contains_key(dev) {
-                diagnostics.push(ResolutionDiagnostic::MissingDev {
-                    dist: dist.clone(),
-                    dev: dev.clone(),
-                });
+            // Validate the development dependency group.
+            if let Some(dev) = dev {
+                if !metadata.dev_dependencies.contains_key(dev) {
+                    diagnostics.push(ResolutionDiagnostic::MissingDev {
+                        dist: dist.clone(),
+                        dev: dev.clone(),
+                    });
+                }
             }
         }
 
         // Add the distribution to the graph.
         let index = petgraph.add_node(ResolutionGraphNode::Dist(AnnotatedDist {
             dist,
+            name: name.clone(),
             version: version.clone(),
             extra: extra.clone(),
             dev: dev.clone(),
@@ -351,7 +354,7 @@ impl ResolutionGraph {
         preferences: &Preferences,
         index: &InMemoryIndex,
         git: &GitResolver,
-    ) -> Result<(ResolvedDist, Vec<HashDigest>, Metadata), ResolveError> {
+    ) -> Result<(ResolvedDist, Vec<HashDigest>, Option<Metadata>), ResolveError> {
         Ok(if let Some(url) = url {
             // Create the distribution.
             let dist = Dist::from_url(name.clone(), url_to_precise(url.clone(), git))?;
@@ -365,17 +368,17 @@ impl ResolutionGraph {
             // Extract the metadata.
             let metadata = {
                 let response = index.distributions().get(&version_id).unwrap_or_else(|| {
-                    panic!("Every package should have metadata: {version_id:?}")
+                    panic!("Every URL distribution should have metadata: {version_id:?}")
                 });
 
                 let MetadataResponse::Found(archive) = &*response else {
-                    panic!("Every package should have metadata: {version_id:?}")
+                    panic!("Every URL distribution should have metadata: {version_id:?}")
                 };
 
                 archive.metadata.clone()
             };
 
-            (dist.into(), hashes, metadata)
+            (dist.into(), hashes, Some(metadata))
         } else {
             let dist = pins
                 .get(name, version)
@@ -406,15 +409,13 @@ impl ResolutionGraph {
 
             // Extract the metadata.
             let metadata = {
-                let response = index.distributions().get(&version_id).unwrap_or_else(|| {
-                    panic!("Every package should have metadata: {version_id:?}")
-                });
-
-                let MetadataResponse::Found(archive) = &*response else {
-                    panic!("Every package should have metadata: {version_id:?}")
-                };
-
-                archive.metadata.clone()
+                index.distributions().get(&version_id).and_then(|response| {
+                    if let MetadataResponse::Found(archive) = &*response {
+                        Some(archive.metadata.clone())
+                    } else {
+                        None
+                    }
+                })
             };
 
             (dist, hashes, metadata)
@@ -726,13 +727,17 @@ fn has_lower_bound(
             return true;
         }
 
+        let Some(metadata) = neighbor_dist.metadata.as_ref() else {
+            // We can't check for lower bounds if we lack metadata.
+            return true;
+        };
+
         // Get all individual specifier for the current package and check if any has a lower
         // bound.
-        for requirement in neighbor_dist
-            .metadata
+        for requirement in metadata
             .requires_dist
             .iter()
-            .chain(neighbor_dist.metadata.dev_dependencies.values().flatten())
+            .chain(metadata.dev_dependencies.values().flatten())
         {
             if requirement.name != *package_name {
                 continue;

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

@@ -24,11 +24,12 @@ mod requirements_txt;
 #[derive(Debug, Clone)]
 pub(crate) struct AnnotatedDist {
     pub(crate) dist: ResolvedDist,
+    pub(crate) name: PackageName,
     pub(crate) version: Version,
     pub(crate) extra: Option<ExtraName>,
     pub(crate) dev: Option<GroupName>,
     pub(crate) hashes: Vec<HashDigest>,
-    pub(crate) metadata: Metadata,
+    pub(crate) metadata: Option<Metadata>,
 }
 
 impl AnnotatedDist {

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

@@ -331,12 +331,14 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                 }
 
                 // Pre-visit all candidate packages, to allow metadata to be fetched in parallel.
-                Self::pre_visit(
-                    state.pubgrub.partial_solution.prioritized_packages(),
-                    &self.urls,
-                    &state.python_requirement,
-                    &request_sink,
-                )?;
+                if self.dependency_mode.is_transitive() {
+                    Self::pre_visit(
+                        state.pubgrub.partial_solution.prioritized_packages(),
+                        &self.urls,
+                        &state.python_requirement,
+                        &request_sink,
+                    )?;
+                }
 
                 // Choose a package version.
                 let Some(highest_priority_pkg) = state
@@ -1109,17 +1111,19 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
 
         // Emit a request to fetch the metadata for this version.
         if matches!(&**package, PubGrubPackageInner::Package { .. }) {
-            if self.index.distributions().register(candidate.version_id()) {
-                // Verify that the package is allowed under the hash-checking policy.
-                if !self
-                    .hasher
-                    .allows_package(candidate.name(), candidate.version())
-                {
-                    return Err(ResolveError::UnhashedPackage(candidate.name().clone()));
-                }
+            if self.dependency_mode.is_transitive() {
+                if self.index.distributions().register(candidate.version_id()) {
+                    // Verify that the package is allowed under the hash-checking policy.
+                    if !self
+                        .hasher
+                        .allows_package(candidate.name(), candidate.version())
+                    {
+                        return Err(ResolveError::UnhashedPackage(candidate.name().clone()));
+                    }
 
-                let request = Request::from(dist.for_resolution());
-                request_sink.blocking_send(request)?;
+                    let request = Request::from(dist.for_resolution());
+                    request_sink.blocking_send(request)?;
+                }
             }
         }
 
@@ -1186,6 +1190,11 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                 dev,
                 marker,
             } => {
+                // If we're excluding transitive dependencies, short-circuit.
+                if self.dependency_mode.is_direct() {
+                    return Ok(Dependencies::Unforkable(Vec::default()));
+                }
+
                 // Determine the distribution to lookup.
                 let dist = match url {
                     Some(url) => PubGrubDistribution::from_url(name, url),
@@ -1273,12 +1282,6 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                     }
                 };
 
-                // If we're excluding transitive dependencies, short-circuit. (It's important that
-                // we fetched the metadata, though, since we need it to validate extras.)
-                if self.dependency_mode.is_direct() {
-                    return Ok(Dependencies::Unforkable(Vec::default()));
-                }
-
                 let requirements = self.flatten_requirements(
                     &metadata.requires_dist,
                     &metadata.dev_dependencies,

crates/uv/tests/cache_clean.rs

@@ -85,7 +85,7 @@ fn clean_package_pypi() -> Result<()> {
     ----- stderr -----
     DEBUG uv [VERSION] ([COMMIT] DATE)
     DEBUG Removing dangling cache entry: [CACHE_DIR]/archive-v0/[ENTRY]
-    Removed 13 files for iniconfig ([SIZE])
+    Removed 12 files for iniconfig ([SIZE])
     "###);
 
     // Assert that the `.rkyv` file is removed for `iniconfig`.
@@ -158,7 +158,7 @@ fn clean_package_index() -> Result<()> {
     ----- stderr -----
     DEBUG uv [VERSION] ([COMMIT] DATE)
     DEBUG Removing dangling cache entry: [CACHE_DIR]/archive-v0/[ENTRY]
-    Removed 13 files for iniconfig ([SIZE])
+    Removed 12 files for iniconfig ([SIZE])
     "###);
 
     // Assert that the `.rkyv` file is removed for `iniconfig`.

crates/uv/tests/cache_prune.rs

@@ -204,7 +204,7 @@ fn prune_unzipped() -> Result<()> {
 
     ----- stderr -----
     Pruning cache at: [CACHE_DIR]/
-    Removed 163 files ([SIZE])
+    Removed 162 files ([SIZE])
     "###);
 
     // Reinstalling the source distribution should not require re-downloading the source
@@ -226,28 +226,20 @@ fn prune_unzipped() -> Result<()> {
      ~ source-distribution==0.0.1
     "###);
 
+    // But reinstalling the other package should require a download, since we pruned the wheel.
     requirements_txt.write_str(indoc! { r"
         iniconfig
     " })?;
     uv_snapshot!(context.filters(), context.pip_sync().env_remove("UV_EXCLUDE_NEWER").arg("requirements.txt").arg("--reinstall").arg("--offline"), @r###"
     success: false
-    exit_code: 1
+    exit_code: 2
     ----- stdout -----
 
     ----- stderr -----
-      × No solution found when resolving dependencies:
-      ╰─▶ Because only the following versions of iniconfig are available:
-              iniconfig<=0.1
-              iniconfig>=1.0.0
-          and all of:
-              iniconfig<=0.1
-              iniconfig>=1.0.0
-          need to be downloaded from a registry, we can conclude that iniconfig<1.0.0 cannot be used.
-          And because you require iniconfig, we can conclude that your requirements are unsatisfiable.
-
-          hint: Pre-releases are available for iniconfig in the requested range (e.g., 0.2.dev0), but pre-releases weren't enabled (try: `--prerelease=allow`)
-
-          hint: Packages were unavailable because the network was disabled. When the network is disabled, registry packages may only be read from the cache.
+    Resolved 1 package in [TIME]
+    error: Failed to prepare distributions
+      Caused by: Failed to fetch wheel: iniconfig==2.0.0
+      Caused by: Network connectivity is disabled, but the requested data wasn't found in the cache for: `https://files.pythonhosted.org/packages/ef/a6/62565a6e1cf69e10f5727360368e451d4b7f58beeac6173dc9db836a5b46/iniconfig-2.0.0-py3-none-any.whl`
     "###);
 
     Ok(())

crates/uv/tests/pip_compile.rs

@@ -6151,7 +6151,7 @@ fn no_deps_valid_extra() -> Result<()> {
     Ok(())
 }
 
-/// Resolve a package with `--no-deps`, including an invalid extra.
+/// Resolve a package with `--no-deps`, including an invalid extra. We don't warn here.
 #[test]
 fn no_deps_invalid_extra() -> Result<()> {
     let context = TestContext::new("3.12");
@@ -6171,7 +6171,6 @@ fn no_deps_invalid_extra() -> Result<()> {
 
     ----- stderr -----
     Resolved 1 package in [TIME]
-    warning: The package `flask==3.0.2` does not have an extra named `empty`
     "###
     );
 

crates/uv/tests/pip_sync.rs

@@ -4783,7 +4783,9 @@ fn require_hashes_find_links_invalid_hash() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    error: Failed to download and build `example-a-961b4c22==1.0.0`
+    Resolved 1 package in [TIME]
+    error: Failed to prepare distributions
+      Caused by: Failed to fetch wheel: example-a-961b4c22==1.0.0
       Caused by: Hash mismatch for `example-a-961b4c22==1.0.0`
 
     Expected:
@@ -4991,7 +4993,9 @@ fn require_hashes_registry_invalid_hash() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    error: Failed to download and build `example-a-961b4c22==1.0.0`
+    Resolved 1 package in [TIME]
+    error: Failed to prepare distributions
+      Caused by: Failed to fetch wheel: example-a-961b4c22==1.0.0
       Caused by: Hash mismatch for `example-a-961b4c22==1.0.0`
 
     Expected:
@@ -5472,7 +5476,9 @@ fn incompatible_build_constraint() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    error: Failed to download and build `requests==1.2.0`
+    Resolved 1 package in [TIME]
+    error: Failed to prepare distributions
+      Caused by: Failed to fetch wheel: requests==1.2.0
       Caused by: Failed to install requirements from `setup.py` build (resolve)
       Caused by: No solution found when resolving: setuptools>=40.8.0
       Caused by: Because you require setuptools>=40.8.0 and setuptools==1, we can conclude that your requirements are unsatisfiable.