remove support for pyx-specific .whl.tar.zst format

crates/uv-client/src/flat_index.rs

@@ -299,7 +299,9 @@ impl<'a> FlatIndexClient<'a> {
     ) -> FlatIndexEntries {
         let entries = files
             .into_iter()
-            .filter_map(|file| {
+            .filter_map(|mut file| {
+                // Ignore deprecated pyx-specific zstd wheel metadata from an older cache entry.
+                file.zstd = None;
                 Some(FlatIndexEntry {
                     filename: DistFilename::try_from_normalized_filename(&file.filename)?,
                     file,
@@ -395,6 +397,32 @@ mod tests {
     use fs_err::File;
     use std::io::Write;
     use tempfile::tempdir;
+    use uv_distribution_types::Zstd;
+
+    /// Round-trip a synthetic cache entry containing deprecated pyx-specific zstd wheel metadata
+    /// and verify that the metadata is discarded before the file is used.
+    #[test]
+    fn cached_files_ignore_deprecated_zstd() -> Result<(), Box<dyn std::error::Error>> {
+        let url = DisplaySafeUrl::parse("https://example.com/flat/")?;
+        let mut files = FlatIndexClient::parse_html(
+            r#"<a href="example-1.0.0-py3-none-any.whl">example-1.0.0-py3-none-any.whl</a>"#,
+            &url,
+        )?;
+        assert_eq!(files.len(), 1);
+        assert!(files[0].zstd.is_none());
+        files[0].zstd = Some(Box::new(Zstd {
+            hashes: HashDigests::empty(),
+            size: Some(42),
+        }));
+
+        let archived = OwnedArchive::from_unarchived(&files)?;
+        let files = OwnedArchive::deserialize(&archived);
+        let entries =
+            FlatIndexClient::entries_from_files(files, &IndexUrl::parse(url.as_str(), None)?);
+        assert_eq!(entries.entries.len(), 1);
+        assert!(entries.entries[0].file.zstd.is_none());
+        Ok(())
+    }
 
     #[test]
     fn read_from_directory_sorts_distributions() {

crates/uv-client/src/registry_client.rs

@@ -1331,6 +1331,9 @@ pub struct CachedFile {
     filename: Option<Box<SmallString>>,
     #[rkyv(with = rkyv::with::Niche)]
     yanked: Option<Box<Yanked>>,
+    /// Deprecated pyx-specific zstd wheel metadata, retained only for compatibility with the
+    /// Simple API cache layout.
+    // TODO: Remove this field when the Simple API cache format is next bumped.
     #[rkyv(with = rkyv::with::Niche)]
     zstd: Option<Box<Zstd>>,
     dist_info_metadata: bool,
@@ -1377,7 +1380,7 @@ impl From<File> for CachedFile {
             has_upload_time,
             url: file.url,
             yanked: file.yanked.filter(|yanked| yanked.is_yanked()),
-            zstd: file.zstd,
+            zstd: None,
         }
     }
 }
@@ -1394,7 +1397,7 @@ impl From<CachedFile> for File {
             upload_time_utc_ms: file.has_upload_time.then_some(file.upload_time_utc_ms),
             url: file.url,
             yanked: file.yanked,
-            zstd: file.zstd,
+            zstd: None,
         }
     }
 }
@@ -1754,7 +1757,7 @@ mod tests {
     use tokio::sync::Semaphore;
     use url::Url;
     use uv_normalize::PackageName;
-    use uv_pypi_types::PypiSimpleDetail;
+    use uv_pypi_types::{HashDigests, PypiSimpleDetail};
     use uv_redacted::DisplaySafeUrl;
     use uv_torch::{TorchBackend, TorchStrategy};
 
@@ -1764,8 +1767,8 @@ mod tests {
     };
     use uv_cache::Cache;
     use uv_distribution_types::{
-        FileLocation, Index, IndexCapabilities, IndexFormat, IndexLocations, IndexMetadataRef,
-        IndexUrl, ToUrlError,
+        File, FileLocation, Index, IndexCapabilities, IndexFormat, IndexLocations,
+        IndexMetadataRef, IndexUrl, ToUrlError, Zstd,
     };
     use uv_small_str::SmallString;
     use wiremock::matchers::{basic_auth, method, path_regex};
@@ -2128,20 +2131,38 @@ mod tests {
         let package_name = PackageName::from_str("example-1")?;
         let data: PypiSimpleDetail = serde_json::from_str(response)?;
         let base = DisplaySafeUrl::parse("https://pypi.org/simple/example-1/")?;
-        let simple_metadata = SimpleDetailMetadata::from_pypi_files(
+        let mut simple_metadata = SimpleDetailMetadata::from_pypi_files(
             data.files,
             &package_name,
             data.project_status,
             &base,
         );
+        let cached_wheel = &mut simple_metadata.versions[0].files.wheels[0];
+        assert!(cached_wheel.zstd.is_none());
+        // An entry written by an older uv may still contain pyx-specific zstd wheel metadata.
+        cached_wheel.zstd = Some(Box::new(Zstd {
+            hashes: HashDigests::empty(),
+            size: Some(42),
+        }));
         let archived = super::OwnedArchive::from_unarchived(&simple_metadata)?;
         let simple_metadata = super::OwnedArchive::deserialize(&archived);
 
         let filenames: Vec<_> = simple_metadata
             .versions
             .into_iter()
             .flat_map(|datum| datum.files.all(&package_name))
-            .map(|(filename, _)| filename.to_string())
+            .map(|(filename, mut file)| {
+                assert!(file.zstd.is_none());
+                // New cache entries must not preserve pyx-specific zstd wheel metadata either.
+                file.zstd = Some(Box::new(Zstd {
+                    hashes: HashDigests::empty(),
+                    size: Some(42),
+                }));
+                let cached = super::CachedFile::from(file);
+                assert!(cached.zstd.is_none());
+                assert!(File::from(cached).zstd.is_none());
+                filename.to_string()
+            })
             .collect();
         assert_eq!(
             filenames,

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

@@ -35,6 +35,9 @@ pub struct File {
     pub upload_time_utc_ms: Option<i64>,
     pub url: FileLocation,
     pub yanked: Option<Box<Yanked>>,
+    /// Deprecated pyx-specific zstd wheel metadata, retained only for compatibility with the
+    /// flat-index cache layout.
+    // TODO: Remove this field when the flat-index cache format is next bumped.
     pub zstd: Option<Box<Zstd>>,
 }
 
@@ -253,6 +256,9 @@ pub enum ToUrlError {
     },
 }
 
+/// Deprecated pyx-specific zstd wheel metadata, retained only for compatibility with existing
+/// cache layouts.
+// TODO: Remove this type once the Simple API and flat-index cache formats are both bumped.
 #[derive(Debug, Clone, PartialEq, Eq, Hash, rkyv::Archive, rkyv::Deserialize, rkyv::Serialize)]
 pub struct Zstd {
     pub hashes: HashDigests,