Error when built wheel is for the wrong platform

crates/uv-bench/benches/uv.rs

@@ -131,7 +131,7 @@ mod resolver {
     );
 
     static TAGS: LazyLock<Tags> = LazyLock::new(|| {
-        Tags::from_env(&PLATFORM, (3, 11), "cpython", (3, 11), false, false).unwrap()
+        Tags::from_env(&PLATFORM, (3, 11), "cpython", (3, 11), false, false, false).unwrap()
     });
 
     pub(crate) async fn resolve(

crates/uv-distribution/src/distribution_database.rs

@@ -385,6 +385,27 @@ impl<'a, Context: BuildContext> DistributionDatabase<'a, Context> {
             .boxed_local()
             .await?;
 
+        // Check that the wheel is compatible with its install target.
+        //
+        // When building a build dependency for a cross-install, the build dependency needs
+        // to install and run on the host instead of the target. In this case the `tags` are already
+        // for the host instead of the target, so this check passes.
+        if !built_wheel.filename.is_compatible(tags) {
+            return if tags.is_cross() {
+                Err(Error::BuiltWheelIncompatibleTargetPlatform {
+                    filename: built_wheel.filename,
+                    python_platform: tags.python_platform().clone(),
+                    python_version: tags.python_version(),
+                })
+            } else {
+                Err(Error::BuiltWheelIncompatibleHostPlatform {
+                    filename: built_wheel.filename,
+                    python_platform: tags.python_platform().clone(),
+                    python_version: tags.python_version(),
+                })
+            };
+        }
+
         // Acquire the advisory lock.
         #[cfg(windows)]
         let _lock = {

crates/uv-distribution/src/error.rs

@@ -6,12 +6,13 @@ use zip::result::ZipError;
 
 use crate::metadata::MetadataError;
 use uv_client::WrappedReqwestError;
-use uv_distribution_filename::WheelFilenameError;
+use uv_distribution_filename::{WheelFilename, WheelFilenameError};
 use uv_distribution_types::{InstalledDist, InstalledDistError, IsBuildBackendError};
 use uv_fs::Simplified;
 use uv_git::GitError;
 use uv_normalize::PackageName;
 use uv_pep440::{Version, VersionSpecifiers};
+use uv_platform_tags::Platform;
 use uv_pypi_types::{HashAlgorithm, HashDigest};
 use uv_redacted::DisplaySafeUrl;
 use uv_types::AnyErrorBuild;
@@ -75,6 +76,35 @@ pub enum Error {
         filename: Version,
         metadata: Version,
     },
+    /// This shouldn't happen, it's a bug in the build backend.
+    #[error(
+        "The built wheel `{}` is not compatible with the current Python {}.{} on {} {}",
+        filename,
+        python_version.0,
+        python_version.1,
+        python_platform.os(),
+        python_platform.arch(),
+    )]
+    BuiltWheelIncompatibleHostPlatform {
+        filename: WheelFilename,
+        python_platform: Platform,
+        python_version: (u8, u8),
+    },
+    /// This may happen when trying to cross-install native dependencies without their build backend
+    /// being aware that the target is a cross-install.
+    #[error(
+        "The built wheel `{}` is not compatible with the target Python {}.{} on {} {}. Consider using `--no-build` to disable building wheels.",
+        filename,
+        python_version.0,
+        python_version.1,
+        python_platform.os(),
+        python_platform.arch(),
+    )]
+    BuiltWheelIncompatibleTargetPlatform {
+        filename: WheelFilename,
+        python_platform: Platform,
+        python_version: (u8, u8),
+    },
     #[error("Failed to parse metadata from built wheel")]
     Metadata(#[from] uv_pypi_types::MetadataError),
     #[error("Failed to read metadata: `{}`", _0.user_display())]

crates/uv-distribution/src/source/mod.rs

@@ -2575,7 +2575,7 @@ impl<'a, T: BuildContext> SourceDistributionBuilder<'a, T> {
         .await
         .map_err(Error::CacheWrite)?;
 
-        debug!("Finished building: {source}");
+        debug!("Built `{source}` into `{disk_filename}`");
         Ok((disk_filename, filename, metadata))
     }
 

crates/uv-platform-tags/src/tags.rs

@@ -79,14 +79,26 @@ pub struct Tags {
     map: Arc<FxHashMap<LanguageTag, FxHashMap<AbiTag, FxHashMap<PlatformTag, TagPriority>>>>,
     /// The highest-priority tag for the Python version and platform.
     best: Option<(LanguageTag, AbiTag, PlatformTag)>,
+    /// Python platform used to generate the tags, for error messages.
+    python_platform: Platform,
+    /// Python version used to generate the tags, for error messages.
+    python_version: (u8, u8),
+    /// Whether the tags are for a different Python interpreter than the current one, for error
+    /// messages.
+    is_cross: bool,
 }
 
 impl Tags {
     /// Create a new set of tags.
     ///
     /// Tags are prioritized based on their position in the given vector. Specifically, tags that
     /// appear earlier in the vector are given higher priority than tags that appear later.
-    pub fn new(tags: Vec<(LanguageTag, AbiTag, PlatformTag)>) -> Self {
+    fn new(
+        tags: Vec<(LanguageTag, AbiTag, PlatformTag)>,
+        python_platform: Platform,
+        python_version: (u8, u8),
+        is_cross: bool,
+    ) -> Self {
         // Store the highest-priority tag for each component.
         let best = tags.first().cloned();
 
@@ -104,6 +116,9 @@ impl Tags {
         Self {
             map: Arc::new(map),
             best,
+            python_platform,
+            python_version,
+            is_cross,
         }
     }
 
@@ -116,6 +131,7 @@ impl Tags {
         implementation_version: (u8, u8),
         manylinux_compatible: bool,
         gil_disabled: bool,
+        is_cross: bool,
     ) -> Result<Self, TagsError> {
         let implementation = Implementation::parse(implementation_name, gil_disabled)?;
 
@@ -219,7 +235,7 @@ impl Tags {
                 ));
             }
         }
-        Ok(Self::new(tags))
+        Ok(Self::new(tags, platform.clone(), python_version, is_cross))
     }
 
     /// Returns true when there exists at least one tag for this platform
@@ -320,6 +336,18 @@ impl Tags {
             .map(|abis| abis.contains_key(&abi_tag))
             .unwrap_or(false)
     }
+
+    pub fn python_platform(&self) -> &Platform {
+        &self.python_platform
+    }
+
+    pub fn python_version(&self) -> (u8, u8) {
+        self.python_version
+    }
+
+    pub fn is_cross(&self) -> bool {
+        self.is_cross
+    }
 }
 
 /// The priority of a platform tag.
@@ -1467,6 +1495,7 @@ mod tests {
             (3, 9),
             false,
             false,
+            false,
         )
         .unwrap();
         assert_snapshot!(
@@ -1530,6 +1559,7 @@ mod tests {
             (3, 9),
             true,
             false,
+            false,
         )
         .unwrap();
         assert_snapshot!(
@@ -2154,6 +2184,7 @@ mod tests {
             (3, 9),
             false,
             false,
+            false,
         )
         .unwrap();
         assert_snapshot!(

crates/uv-python/src/interpreter.rs

@@ -253,6 +253,7 @@ impl Interpreter {
                 self.implementation_tuple(),
                 self.manylinux_compatible,
                 self.gil_disabled,
+                false,
             )?;
             self.tags.set(tags).expect("tags should not be set");
         }

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

@@ -56,7 +56,7 @@ use uv_workspace::WorkspaceCache;
 use uv_workspace::pyproject::ExtraBuildDependencies;
 
 use crate::commands::pip::loggers::DefaultResolveLogger;
-use crate::commands::pip::{operations, resolution_environment};
+use crate::commands::pip::{operations, resolution_markers, resolution_tags};
 use crate::commands::{ExitStatus, OutputWriter, diagnostics};
 use crate::printer::Printer;
 
@@ -392,8 +392,16 @@ pub(crate) async fn pip_compile(
             ResolverEnvironment::universal(environments.into_markers()),
         )
     } else {
-        let (tags, marker_env) =
-            resolution_environment(python_version, python_platform, &interpreter)?;
+        let tags = resolution_tags(
+            python_version.as_ref(),
+            python_platform.as_ref(),
+            &interpreter,
+        )?;
+        let marker_env = resolution_markers(
+            python_version.as_ref(),
+            python_platform.as_ref(),
+            &interpreter,
+        );
         (Some(tags), ResolverEnvironment::specific(marker_env))
     };
 

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

@@ -42,82 +42,33 @@ pub(crate) fn resolution_tags<'env>(
     python_platform: Option<&TargetTriple>,
     interpreter: &'env Interpreter,
 ) -> Result<Cow<'env, Tags>, TagsError> {
-    Ok(match (python_platform, python_version.as_ref()) {
-        (Some(python_platform), Some(python_version)) => Cow::Owned(Tags::from_env(
-            &python_platform.platform(),
-            (python_version.major(), python_version.minor()),
-            interpreter.implementation_name(),
-            interpreter.implementation_tuple(),
-            python_platform.manylinux_compatible(),
-            interpreter.gil_disabled(),
-        )?),
-        (Some(python_platform), None) => Cow::Owned(Tags::from_env(
-            &python_platform.platform(),
-            interpreter.python_tuple(),
-            interpreter.implementation_name(),
-            interpreter.implementation_tuple(),
-            python_platform.manylinux_compatible(),
-            interpreter.gil_disabled(),
-        )?),
-        (None, Some(python_version)) => Cow::Owned(Tags::from_env(
-            interpreter.platform(),
-            (python_version.major(), python_version.minor()),
-            interpreter.implementation_name(),
-            interpreter.implementation_tuple(),
-            interpreter.manylinux_compatible(),
-            interpreter.gil_disabled(),
-        )?),
-        (None, None) => Cow::Borrowed(interpreter.tags()?),
-    })
-}
+    if python_platform.is_none() && python_version.is_none() {
+        return Ok(Cow::Borrowed(interpreter.tags()?));
+    }
 
-/// Determine the tags, markers, and interpreter to use for resolution.
-pub(crate) fn resolution_environment(
-    python_version: Option<PythonVersion>,
-    python_platform: Option<TargetTriple>,
-    interpreter: &Interpreter,
-) -> Result<(Cow<'_, Tags>, ResolverMarkerEnvironment), TagsError> {
-    let tags = match (python_platform, python_version.as_ref()) {
-        (Some(python_platform), Some(python_version)) => Cow::Owned(Tags::from_env(
+    let (platform, manylinux_compatible) = if let Some(python_platform) = python_platform {
+        (
             &python_platform.platform(),
-            (python_version.major(), python_version.minor()),
-            interpreter.implementation_name(),
-            interpreter.implementation_tuple(),
             python_platform.manylinux_compatible(),
-            interpreter.gil_disabled(),
-        )?),
-        (Some(python_platform), None) => Cow::Owned(Tags::from_env(
-            &python_platform.platform(),
-            interpreter.python_tuple(),
-            interpreter.implementation_name(),
-            interpreter.implementation_tuple(),
-            python_platform.manylinux_compatible(),
-            interpreter.gil_disabled(),
-        )?),
-        (None, Some(python_version)) => Cow::Owned(Tags::from_env(
-            interpreter.platform(),
-            (python_version.major(), python_version.minor()),
-            interpreter.implementation_name(),
-            interpreter.implementation_tuple(),
-            interpreter.manylinux_compatible(),
-            interpreter.gil_disabled(),
-        )?),
-        (None, None) => Cow::Borrowed(interpreter.tags()?),
+        )
+    } else {
+        (interpreter.platform(), interpreter.manylinux_compatible())
     };
 
-    // Apply the platform tags to the markers.
-    let markers = match (python_platform, python_version) {
-        (Some(python_platform), Some(python_version)) => ResolverMarkerEnvironment::from(
-            python_version.markers(&python_platform.markers(interpreter.markers())),
-        ),
-        (Some(python_platform), None) => {
-            ResolverMarkerEnvironment::from(python_platform.markers(interpreter.markers()))
-        }
-        (None, Some(python_version)) => {
-            ResolverMarkerEnvironment::from(python_version.markers(interpreter.markers()))
-        }
-        (None, None) => interpreter.resolver_marker_environment(),
+    let version_tuple = if let Some(python_version) = python_version {
+        (python_version.major(), python_version.minor())
+    } else {
+        interpreter.python_tuple()
     };
 
-    Ok((tags, markers))
+    let tags = Tags::from_env(
+        platform,
+        version_tuple,
+        interpreter.implementation_name(),
+        interpreter.implementation_tuple(),
+        manylinux_compatible,
+        interpreter.gil_disabled(),
+        true,
+    )?;
+    Ok(Cow::Owned(tags))
 }

crates/uv/tests/it/common/mod.rs

@@ -560,8 +560,8 @@ impl TestContext {
     }
 
     /// Add a custom filter to the `TestContext`.
-    pub fn with_filter(mut self, filter: (String, String)) -> Self {
-        self.filters.push(filter);
+    pub fn with_filter(mut self, filter: (impl Into<String>, impl Into<String>)) -> Self {
+        self.filters.push((filter.0.into(), filter.1.into()));
         self
     }