Store unsupported tags in wheel filename (#10665)

## Summary

We can retain the small-size advantage of our new tags by moving the
"unknown tag" case into `WheelTagLarge`. This ensures that we can still
represent unknown tags, but avoid paying the cost for them.

crates/uv-distribution-filename/src/lib.rs

@@ -7,7 +7,7 @@ pub use build_tag::{BuildTag, BuildTagError};
 pub use egg::{EggInfoFilename, EggInfoFilenameError};
 pub use extension::{DistExtension, ExtensionError, SourceDistExtension};
 pub use source_dist::{SourceDistFilename, SourceDistFilenameError};
-pub use wheel::{TagSet, WheelFilename, WheelFilenameError};
+pub use wheel::{WheelFilename, WheelFilenameError};
 
 mod build_tag;
 mod egg;
@@ -15,6 +15,7 @@ mod extension;
 mod source_dist;
 mod splitter;
 mod wheel;
+mod wheel_tag;
 
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub enum DistFilename {
@@ -97,13 +98,9 @@ impl Display for DistFilename {
 #[cfg(test)]
 mod tests {
     use crate::WheelFilename;
-    use uv_platform_tags::{AbiTag, LanguageTag, PlatformTag};
 
     #[test]
     fn wheel_filename_size() {
-        assert_eq!(size_of::<WheelFilename>(), 72);
+        assert_eq!(size_of::<WheelFilename>(), 48);
-        assert_eq!(size_of::<LanguageTag>(), 16);
-        assert_eq!(size_of::<AbiTag>(), 16);
-        assert_eq!(size_of::<PlatformTag>(), 16);
     }
 }

crates/uv-distribution-filename/src/snapshots/uv_distribution_filename__wheel__tests__ok_build_tag.snap

@@ -28,6 +28,7 @@ Ok(
                 platform_tag: [
                     Any,
                 ],
+                repr: "202206090410-py3-none-any",
             },
         },
     },

crates/uv-distribution-filename/src/snapshots/uv_distribution_filename__wheel__tests__ok_multiple_tags.snap

@@ -38,6 +38,7 @@ Ok(
                         arch: X86_64,
                     },
                 ],
+                repr: "cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64",
             },
         },
     },

crates/uv-distribution-filename/src/wheel.rs

@@ -14,6 +14,7 @@ use uv_platform_tags::{
 };
 
 use crate::splitter::MemchrSplitter;
+use crate::wheel_tag::{WheelTag, WheelTagLarge, WheelTagSmall};
 use crate::{BuildTag, BuildTagError};
 
 #[derive(
@@ -177,7 +178,7 @@ impl WheelFilename {
             ));
         };
 
-        let (name, version, build_tag, python_tag, abi_tag, platform_tag, is_large) =
+        let (name, version, build_tag, python_tag, abi_tag, platform_tag, is_small) =
             if let Some(platform_tag) = splitter.next() {
                 if splitter.next().is_some() {
                     return Err(WheelFilenameError::InvalidWheelFileName(
@@ -193,7 +194,7 @@ impl WheelFilename {
                     &stem[abi_tag_or_platform_tag + 1..platform_tag],
                     &stem[platform_tag + 1..],
                     // Always take the slow path if a build tag is present.
-                    true,
+                    false,
                 )
             } else {
                 (
@@ -206,7 +207,7 @@ impl WheelFilename {
                     // Determine whether any of the tag types contain a period, which would indicate
                     // that at least one of the tag types includes multiple tags (which in turn
                     // necessitates taking the slow path).
-                    memchr(b'.', stem[build_tag_or_python_tag..].as_bytes()).is_some(),
+                    memchr(b'.', stem[build_tag_or_python_tag..].as_bytes()).is_none(),
                 )
             };
 
@@ -221,44 +222,38 @@ impl WheelFilename {
             })
             .transpose()?;
 
-        let tags = if is_large {
+        let tags = if let Some(small) = is_small
+            .then(|| {
+                Some(WheelTagSmall {
+                    python_tag: LanguageTag::from_str(python_tag).ok()?,
+                    abi_tag: AbiTag::from_str(abi_tag).ok()?,
+                    platform_tag: PlatformTag::from_str(platform_tag).ok()?,
+                })
+            })
+            .flatten()
+        {
+            WheelTag::Small { small }
+        } else {
+            // Store the plaintext representation of the tags.
+            let repr = &stem[build_tag_or_python_tag + 1..];
             WheelTag::Large {
                 large: Box::new(WheelTagLarge {
                     build_tag,
                     python_tag: MemchrSplitter::split(python_tag, b'.')
                         .map(LanguageTag::from_str)
-                        .collect::<Result<_, _>>()
+                        .filter_map(Result::ok)
-                        .map_err(|err| {
+                        .collect(),
-                            WheelFilenameError::InvalidLanguageTag(filename.to_string(), err)
-                        })?,
                     abi_tag: MemchrSplitter::split(abi_tag, b'.')
                         .map(AbiTag::from_str)
-                        .collect::<Result<_, _>>()
+                        .filter_map(Result::ok)
-                        .map_err(|err| {
+                        .collect(),
-                            WheelFilenameError::InvalidAbiTag(filename.to_string(), err)
-                        })?,
                     platform_tag: MemchrSplitter::split(platform_tag, b'.')
                         .map(PlatformTag::from_str)
-                        .collect::<Result<_, _>>()
+                        .filter_map(Result::ok)
-                        .map_err(|err| {
+                        .collect(),
-                            WheelFilenameError::InvalidPlatformTag(filename.to_string(), err)
+                    repr: repr.into(),
-                        })?,
                 }),
             }
-        } else {
-            WheelTag::Small {
-                small: WheelTagSmall {
-                    python_tag: LanguageTag::from_str(python_tag).map_err(|err| {
-                        WheelFilenameError::InvalidLanguageTag(filename.to_string(), err)
-                    })?,
-                    abi_tag: AbiTag::from_str(abi_tag).map_err(|err| {
-                        WheelFilenameError::InvalidAbiTag(filename.to_string(), err)
-                    })?,
-                    platform_tag: PlatformTag::from_str(platform_tag).map_err(|err| {
-                        WheelFilenameError::InvalidPlatformTag(filename.to_string(), err)
-                    })?,
-                },
-            }
         };
 
         Ok(Self {
@@ -311,124 +306,6 @@ impl Serialize for WheelFilename {
     }
 }
 
-/// A [`SmallVec`] type for storing tags.
-///
-/// Wheels tend to include a single language, ABI, and platform tag, so we use a [`SmallVec`] with a
-/// capacity of 1 to optimize for this common case.
-pub type TagSet<T> = smallvec::SmallVec<[T; 3]>;
-
-/// The portion of the wheel filename following the name and version: the optional build tag, along
-/// with the Python tag(s), ABI tag(s), and platform tag(s).
-///
-/// Most wheels consist of a single Python, ABI, and platform tag (and no build tag). We represent
-/// such wheels with [`WheelTagSmall`], a variant with a smaller memory footprint and (generally)
-/// zero allocations. The [`WheelTagLarge`] variant is used for wheels with multiple tags and/or a
-/// build tag.
-#[derive(
-    Debug,
-    Clone,
-    Eq,
-    PartialEq,
-    Ord,
-    PartialOrd,
-    Hash,
-    rkyv::Archive,
-    rkyv::Deserialize,
-    rkyv::Serialize,
-)]
-#[rkyv(derive(Debug))]
-enum WheelTag {
-    Small { small: WheelTagSmall },
-    Large { large: Box<WheelTagLarge> },
-}
-
-impl Display for WheelTag {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        match self {
-            Self::Small { small } => write!(f, "{small}"),
-            Self::Large { large } => write!(f, "{large}"),
-        }
-    }
-}
-
-#[derive(
-    Debug,
-    Clone,
-    Eq,
-    PartialEq,
-    Ord,
-    PartialOrd,
-    Hash,
-    rkyv::Archive,
-    rkyv::Deserialize,
-    rkyv::Serialize,
-)]
-#[rkyv(derive(Debug))]
-#[allow(clippy::struct_field_names)]
-struct WheelTagSmall {
-    python_tag: LanguageTag,
-    abi_tag: AbiTag,
-    platform_tag: PlatformTag,
-}
-
-impl Display for WheelTagSmall {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        write!(
-            f,
-            "{}-{}-{}",
-            self.python_tag, self.abi_tag, self.platform_tag
-        )
-    }
-}
-
-#[derive(
-    Debug,
-    Clone,
-    Eq,
-    PartialEq,
-    Ord,
-    PartialOrd,
-    Hash,
-    rkyv::Archive,
-    rkyv::Deserialize,
-    rkyv::Serialize,
-)]
-#[rkyv(derive(Debug))]
-#[allow(clippy::struct_field_names)]
-pub struct WheelTagLarge {
-    build_tag: Option<BuildTag>,
-    python_tag: TagSet<LanguageTag>,
-    abi_tag: TagSet<AbiTag>,
-    platform_tag: TagSet<PlatformTag>,
-}
-
-impl Display for WheelTagLarge {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        if let Some(build_tag) = &self.build_tag {
-            write!(f, "{build_tag}-")?;
-        }
-        write!(
-            f,
-            "{}-{}-{}",
-            self.python_tag
-                .iter()
-                .map(ToString::to_string)
-                .collect::<Vec<_>>()
-                .join("."),
-            self.abi_tag
-                .iter()
-                .map(ToString::to_string)
-                .collect::<Vec<_>>()
-                .join("."),
-            self.platform_tag
-                .iter()
-                .map(ToString::to_string)
-                .collect::<Vec<_>>()
-                .join("."),
-        )
-    }
-}
-
 #[derive(Error, Debug)]
 pub enum WheelFilenameError {
     #[error("The wheel filename \"{0}\" is invalid: {1}")]

crates/uv-distribution-filename/src/wheel_tag.rs

@@ -0,0 +1,115 @@
+use std::fmt::{Display, Formatter};
+
+use crate::BuildTag;
+use uv_platform_tags::{AbiTag, LanguageTag, PlatformTag};
+use uv_small_str::SmallString;
+
+/// A [`SmallVec`] type for storing tags.
+///
+/// Wheels tend to include a single language, ABI, and platform tag, so we use a [`SmallVec`] with a
+/// capacity of 1 to optimize for this common case.
+pub(crate) type TagSet<T> = smallvec::SmallVec<[T; 3]>;
+
+/// The portion of the wheel filename following the name and version: the optional build tag, along
+/// with the Python tag(s), ABI tag(s), and platform tag(s).
+///
+/// Most wheels consist of a single Python, ABI, and platform tag (and no build tag). We represent
+/// such wheels with [`WheelTagSmall`], a variant with a smaller memory footprint and (generally)
+/// zero allocations. The [`WheelTagLarge`] variant is used for wheels with multiple tags, a build
+/// tag, or an unsupported tag (i.e., a tag that can't be represented by [`LanguageTag`],
+/// [`AbiTag`], or [`PlatformTag`]). (Unsupported tags are filtered out, but retained in the display
+/// representation of [`WheelTagLarge`].)
+#[derive(
+    Debug,
+    Clone,
+    Eq,
+    PartialEq,
+    Ord,
+    PartialOrd,
+    Hash,
+    rkyv::Archive,
+    rkyv::Deserialize,
+    rkyv::Serialize,
+)]
+#[rkyv(derive(Debug))]
+pub(crate) enum WheelTag {
+    Small { small: WheelTagSmall },
+    Large { large: Box<WheelTagLarge> },
+}
+
+impl Display for WheelTag {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Small { small } => write!(f, "{small}"),
+            Self::Large { large } => write!(f, "{large}"),
+        }
+    }
+}
+
+#[derive(
+    Debug,
+    Clone,
+    Eq,
+    PartialEq,
+    Ord,
+    PartialOrd,
+    Hash,
+    rkyv::Archive,
+    rkyv::Deserialize,
+    rkyv::Serialize,
+)]
+#[rkyv(derive(Debug))]
+#[allow(clippy::struct_field_names)]
+pub(crate) struct WheelTagSmall {
+    /// The Python tag, e.g., `py3` in `1.2.3-py3-none-any`.
+    pub(crate) python_tag: LanguageTag,
+    /// The ABI tag, e.g., `none` in `1.2.3-py3-none-any`.
+    pub(crate) abi_tag: AbiTag,
+    /// The platform tag, e.g., `none` in `1.2.3-py3-none-any`.
+    pub(crate) platform_tag: PlatformTag,
+}
+
+impl Display for WheelTagSmall {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "{}-{}-{}",
+            self.python_tag, self.abi_tag, self.platform_tag
+        )
+    }
+}
+
+#[derive(
+    Debug,
+    Clone,
+    Eq,
+    PartialEq,
+    Ord,
+    PartialOrd,
+    Hash,
+    rkyv::Archive,
+    rkyv::Deserialize,
+    rkyv::Serialize,
+)]
+#[rkyv(derive(Debug))]
+#[allow(clippy::struct_field_names)]
+pub(crate) struct WheelTagLarge {
+    /// The optional build tag, e.g., `73` in `1.2.3-73-py3-none-any`.
+    pub(crate) build_tag: Option<BuildTag>,
+    /// The Python tag(s), e.g., `py3` in `1.2.3-73-py3-none-any`.
+    pub(crate) python_tag: TagSet<LanguageTag>,
+    /// The ABI tag(s), e.g., `none` in `1.2.3-73-py3-none-any`.
+    pub(crate) abi_tag: TagSet<AbiTag>,
+    /// The platform tag(s), e.g., `none` in `1.2.3-73-py3-none-any`.
+    pub(crate) platform_tag: TagSet<PlatformTag>,
+    /// The string representation of the tag.
+    ///
+    /// Preserves any unsupported tags that were filtered out when parsing the wheel filename.
+    pub(crate) repr: SmallString,
+}
+
+impl Display for WheelTagLarge {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.repr)
+    }
+}

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

@@ -1343,8 +1343,8 @@ mod test {
     /// Ensure that we don't accidentally grow the `Dist` sizes.
     #[test]
     fn dist_size() {
-        assert!(size_of::<Dist>() <= 208, "{}", size_of::<Dist>());
+        assert!(size_of::<Dist>() <= 200, "{}", size_of::<Dist>());
-        assert!(size_of::<BuiltDist>() <= 208, "{}", size_of::<BuiltDist>());
+        assert!(size_of::<BuiltDist>() <= 200, "{}", size_of::<BuiltDist>());
         assert!(
             size_of::<SourceDist>() <= 176,
             "{}",

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

@@ -523,20 +523,20 @@ impl PrioritizedDist {
     }
 
     /// Returns the set of all Python tags for the distribution.
-    pub fn python_tags(&self) -> BTreeSet<&LanguageTag> {
+    pub fn python_tags(&self) -> BTreeSet<LanguageTag> {
         self.0
             .wheels
             .iter()
-            .flat_map(|(wheel, _)| wheel.filename.python_tags().iter())
+            .flat_map(|(wheel, _)| wheel.filename.python_tags().iter().copied())
             .collect()
     }
 
     /// Returns the set of all ABI tags for the distribution.
-    pub fn abi_tags(&self) -> BTreeSet<&AbiTag> {
+    pub fn abi_tags(&self) -> BTreeSet<AbiTag> {
         self.0
             .wheels
             .iter()
-            .flat_map(|(wheel, _)| wheel.filename.abi_tags().iter())
+            .flat_map(|(wheel, _)| wheel.filename.abi_tags().iter().copied())
             .collect()
     }
 
@@ -547,7 +547,7 @@ impl PrioritizedDist {
         for (wheel, _) in &self.0.wheels {
             for wheel_py in wheel.filename.python_tags() {
                 for wheel_abi in wheel.filename.abi_tags() {
-                    if tags.is_compatible_abi(wheel_py, wheel_abi) {
+                    if tags.is_compatible_abi(*wheel_py, *wheel_abi) {
                         candidates.extend(wheel.filename.platform_tags().iter());
                     }
                 }

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

@@ -1,14 +1,13 @@
 use std::fmt::Formatter;
 use std::str::FromStr;
 
-use uv_small_str::SmallString;
-
 /// A tag to represent the ABI compatibility of a Python distribution.
 ///
 /// This is the second segment in the wheel filename, following the language tag. For example,
 /// in `cp39-none-manylinux_2_24_x86_64.whl`, the ABI tag is `none`.
 #[derive(
     Debug,
+    Copy,
     Clone,
     Eq,
     PartialEq,
@@ -42,13 +41,11 @@ pub enum AbiTag {
     },
     /// Ex) `pyston_23_x86_64_linux_gnu`
     Pyston { implementation_version: (u8, u8) },
-    /// Ex) `pypy_73`
-    Unknown { tag: SmallString },
 }
 
 impl AbiTag {
     /// Return a pretty string representation of the ABI tag.
-    pub fn pretty(&self) -> Option<String> {
+    pub fn pretty(self) -> Option<String> {
         match self {
             AbiTag::None => None,
             AbiTag::Abi3 => None,
@@ -70,7 +67,6 @@ impl AbiTag {
                 implementation_version.0, implementation_version.1
             )),
             AbiTag::Pyston { .. } => Some("Pyston".to_string()),
-            AbiTag::Unknown { .. } => None,
         }
     }
 }
@@ -121,14 +117,16 @@ impl std::fmt::Display for AbiTag {
             } => {
                 write!(f, "pyston_{impl_major}{impl_minor}_x86_64_linux_gnu")
             }
-            Self::Unknown { tag } => write!(f, "{tag}"),
         }
     }
 }
 
-impl AbiTag {
+impl FromStr for AbiTag {
+    type Err = ParseAbiTagError;
+
     /// Parse an [`AbiTag`] from a string.
-    fn parse(s: &str) -> Result<Self, ParseAbiTagError> {
+    #[allow(clippy::cast_possible_truncation)]
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
         /// Parse a Python version from a string (e.g., convert `39` into `(3, 9)`).
         fn parse_python_version(
             version_str: &str,
@@ -290,14 +288,6 @@ impl AbiTag {
     }
 }
 
-impl FromStr for AbiTag {
-    type Err = ParseAbiTagError;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        Ok(AbiTag::parse(s).unwrap_or_else(|_| AbiTag::Unknown { tag: s.into() }))
-    }
-}
-
 #[derive(Debug, thiserror::Error, PartialEq, Eq)]
 pub enum ParseAbiTagError {
     #[error("Unknown ABI tag format: {0}")]
@@ -351,17 +341,19 @@ pub enum ParseAbiTagError {
 
 #[cfg(test)]
 mod tests {
+    use std::str::FromStr;
+
     use crate::abi_tag::{AbiTag, ParseAbiTagError};
 
     #[test]
     fn none_abi() {
-        assert_eq!(AbiTag::parse("none"), Ok(AbiTag::None));
+        assert_eq!(AbiTag::from_str("none"), Ok(AbiTag::None));
         assert_eq!(AbiTag::None.to_string(), "none");
     }
 
     #[test]
     fn abi3() {
-        assert_eq!(AbiTag::parse("abi3"), Ok(AbiTag::Abi3));
+        assert_eq!(AbiTag::from_str("abi3"), Ok(AbiTag::Abi3));
         assert_eq!(AbiTag::Abi3.to_string(), "abi3");
     }
 
@@ -371,25 +363,25 @@ mod tests {
             gil_disabled: false,
             python_version: (3, 9),
         };
-        assert_eq!(AbiTag::parse("cp39").as_ref(), Ok(&tag));
+        assert_eq!(AbiTag::from_str("cp39"), Ok(tag));
         assert_eq!(tag.to_string(), "cp39");
 
         let tag = AbiTag::CPython {
             gil_disabled: false,
             python_version: (3, 7),
         };
-        assert_eq!(AbiTag::parse("cp37m").as_ref(), Ok(&tag));
+        assert_eq!(AbiTag::from_str("cp37m"), Ok(tag));
         assert_eq!(tag.to_string(), "cp37m");
 
         let tag = AbiTag::CPython {
             gil_disabled: true,
             python_version: (3, 13),
         };
-        assert_eq!(AbiTag::parse("cp313t").as_ref(), Ok(&tag));
+        assert_eq!(AbiTag::from_str("cp313t"), Ok(tag));
         assert_eq!(tag.to_string(), "cp313t");
 
         assert_eq!(
-            AbiTag::parse("cpXY"),
+            AbiTag::from_str("cpXY"),
             Err(ParseAbiTagError::MissingMajorVersion {
                 implementation: "CPython",
                 tag: "cpXY".to_string()
@@ -403,32 +395,32 @@ mod tests {
             python_version: Some((3, 9)),
             implementation_version: (7, 3),
         };
-        assert_eq!(AbiTag::parse("pypy39_pp73").as_ref(), Ok(&tag));
+        assert_eq!(AbiTag::from_str("pypy39_pp73"), Ok(tag));
         assert_eq!(tag.to_string(), "pypy39_pp73");
 
         let tag = AbiTag::PyPy {
             python_version: None,
             implementation_version: (7, 3),
         };
-        assert_eq!(AbiTag::parse("pypy_73").as_ref(), Ok(&tag));
+        assert_eq!(AbiTag::from_str("pypy_73").as_ref(), Ok(&tag));
         assert_eq!(tag.to_string(), "pypy_73");
 
         assert_eq!(
-            AbiTag::parse("pypy39"),
+            AbiTag::from_str("pypy39"),
             Err(ParseAbiTagError::InvalidFormat {
                 implementation: "PyPy",
                 tag: "pypy39".to_string()
             })
         );
         assert_eq!(
-            AbiTag::parse("pypy39_73"),
+            AbiTag::from_str("pypy39_73"),
             Err(ParseAbiTagError::InvalidFormat {
                 implementation: "PyPy",
                 tag: "pypy39_73".to_string()
             })
         );
         assert_eq!(
-            AbiTag::parse("pypy39_ppXY"),
+            AbiTag::from_str("pypy39_ppXY"),
             Err(ParseAbiTagError::InvalidImplMajorVersion {
                 implementation: "PyPy",
                 tag: "pypy39_ppXY".to_string()
@@ -443,27 +435,27 @@ mod tests {
             implementation_version: (2, 40),
         };
         assert_eq!(
-            AbiTag::parse("graalpy310_graalpy240_310_native").as_ref(),
+            AbiTag::from_str("graalpy310_graalpy240_310_native"),
-            Ok(&tag)
+            Ok(tag)
         );
         assert_eq!(tag.to_string(), "graalpy310_graalpy240_310_native");
 
         assert_eq!(
-            AbiTag::parse("graalpy310"),
+            AbiTag::from_str("graalpy310"),
             Err(ParseAbiTagError::InvalidFormat {
                 implementation: "GraalPy",
                 tag: "graalpy310".to_string()
             })
         );
         assert_eq!(
-            AbiTag::parse("graalpy310_240"),
+            AbiTag::from_str("graalpy310_240"),
             Err(ParseAbiTagError::InvalidFormat {
                 implementation: "GraalPy",
                 tag: "graalpy310_240".to_string()
             })
         );
         assert_eq!(
-            AbiTag::parse("graalpy310_graalpyXY"),
+            AbiTag::from_str("graalpy310_graalpyXY"),
             Err(ParseAbiTagError::InvalidFormat {
                 implementation: "GraalPy",
                 tag: "graalpy310_graalpyXY".to_string()
@@ -476,21 +468,18 @@ mod tests {
         let tag = AbiTag::Pyston {
             implementation_version: (2, 3),
         };
-        assert_eq!(
+        assert_eq!(AbiTag::from_str("pyston_23_x86_64_linux_gnu"), Ok(tag));
-            AbiTag::parse("pyston_23_x86_64_linux_gnu").as_ref(),
-            Ok(&tag)
-        );
         assert_eq!(tag.to_string(), "pyston_23_x86_64_linux_gnu");
 
         assert_eq!(
-            AbiTag::parse("pyston23_x86_64_linux_gnu"),
+            AbiTag::from_str("pyston23_x86_64_linux_gnu"),
             Err(ParseAbiTagError::InvalidFormat {
                 implementation: "Pyston",
                 tag: "pyston23_x86_64_linux_gnu".to_string()
             })
         );
         assert_eq!(
-            AbiTag::parse("pyston_XY_x86_64_linux_gnu"),
+            AbiTag::from_str("pyston_XY_x86_64_linux_gnu"),
             Err(ParseAbiTagError::InvalidImplMajorVersion {
                 implementation: "Pyston",
                 tag: "pyston_XY_x86_64_linux_gnu".to_string()
@@ -501,11 +490,11 @@ mod tests {
     #[test]
     fn unknown_abi() {
         assert_eq!(
-            AbiTag::parse("unknown"),
+            AbiTag::from_str("unknown"),
             Err(ParseAbiTagError::UnknownFormat("unknown".to_string()))
         );
         assert_eq!(
-            AbiTag::parse(""),
+            AbiTag::from_str(""),
             Err(ParseAbiTagError::UnknownFormat(String::new()))
         );
     }

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

@@ -1,14 +1,13 @@
 use std::fmt::Formatter;
 use std::str::FromStr;
 
-use uv_small_str::SmallString;
-
 /// A tag to represent the language and implementation of the Python interpreter.
 ///
 /// This is the first segment in the wheel filename. For example, in `cp39-none-manylinux_2_24_x86_64.whl`,
 /// the language tag is `cp39`.
 #[derive(
     Debug,
+    Copy,
     Clone,
     Eq,
     PartialEq,
@@ -33,13 +32,11 @@ pub enum LanguageTag {
     GraalPy { python_version: (u8, u8) },
     /// Ex) `pyston38`
     Pyston { python_version: (u8, u8) },
-    /// Ex) `ironpython27`
-    Unknown { tag: SmallString },
 }
 
 impl LanguageTag {
     /// Return a pretty string representation of the language tag.
-    pub fn pretty(&self) -> Option<String> {
+    pub fn pretty(self) -> Option<String> {
         match self {
             Self::None => None,
             Self::Python { major, minor } => {
@@ -61,7 +58,6 @@ impl LanguageTag {
             Self::Pyston {
                 python_version: (major, minor),
             } => Some(format!("Pyston {major}.{minor}")),
-            Self::Unknown { .. } => None,
         }
     }
 }
@@ -98,15 +94,16 @@ impl std::fmt::Display for LanguageTag {
             } => {
                 write!(f, "pyston{major}{minor}")
             }
-            Self::Unknown { tag } => write!(f, "{tag}"),
         }
     }
 }
 
-impl LanguageTag {
+impl FromStr for LanguageTag {
+    type Err = ParseLanguageTagError;
+
     /// Parse a [`LanguageTag`] from a string.
     #[allow(clippy::cast_possible_truncation)]
-    fn parse(s: &str) -> Result<Self, ParseLanguageTagError> {
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
         /// Parse a Python version from a string (e.g., convert `39` into `(3, 9)`).
         fn parse_python_version(
             version_str: &str,
@@ -209,14 +206,6 @@ impl LanguageTag {
     }
 }
 
-impl FromStr for LanguageTag {
-    type Err = ParseLanguageTagError;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        Ok(LanguageTag::parse(s).unwrap_or_else(|_| LanguageTag::Unknown { tag: s.into() }))
-    }
-}
-
 #[derive(Debug, thiserror::Error, PartialEq, Eq)]
 pub enum ParseLanguageTagError {
     #[error("Unknown language tag format: {0}")]
@@ -245,13 +234,14 @@ pub enum ParseLanguageTagError {
 
 #[cfg(test)]
 mod tests {
+    use std::str::FromStr;
 
     use crate::language_tag::ParseLanguageTagError;
     use crate::LanguageTag;
 
     #[test]
     fn none() {
-        assert_eq!(LanguageTag::parse("none"), Ok(LanguageTag::None));
+        assert_eq!(LanguageTag::from_str("none"), Ok(LanguageTag::None));
         assert_eq!(LanguageTag::None.to_string(), "none");
     }
 
@@ -261,32 +251,32 @@ mod tests {
             major: 3,
             minor: None,
         };
-        assert_eq!(LanguageTag::parse("py3").as_ref(), Ok(&tag));
+        assert_eq!(LanguageTag::from_str("py3"), Ok(tag));
         assert_eq!(tag.to_string(), "py3");
 
         let tag = LanguageTag::Python {
             major: 3,
             minor: Some(9),
         };
-        assert_eq!(LanguageTag::parse("py39").as_ref(), Ok(&tag));
+        assert_eq!(LanguageTag::from_str("py39"), Ok(tag));
         assert_eq!(tag.to_string(), "py39");
 
         assert_eq!(
-            LanguageTag::parse("py"),
+            LanguageTag::from_str("py"),
             Err(ParseLanguageTagError::MissingMajorVersion {
                 implementation: "Python",
                 tag: "py".to_string()
             })
         );
         assert_eq!(
-            LanguageTag::parse("pyX"),
+            LanguageTag::from_str("pyX"),
             Err(ParseLanguageTagError::InvalidMajorVersion {
                 implementation: "Python",
                 tag: "pyX".to_string()
             })
         );
         assert_eq!(
-            LanguageTag::parse("py3X"),
+            LanguageTag::from_str("py3X"),
             Err(ParseLanguageTagError::InvalidMinorVersion {
                 implementation: "Python",
                 tag: "py3X".to_string()
@@ -299,25 +289,25 @@ mod tests {
         let tag = LanguageTag::CPython {
             python_version: (3, 9),
         };
-        assert_eq!(LanguageTag::parse("cp39").as_ref(), Ok(&tag));
+        assert_eq!(LanguageTag::from_str("cp39"), Ok(tag));
         assert_eq!(tag.to_string(), "cp39");
 
         assert_eq!(
-            LanguageTag::parse("cp"),
+            LanguageTag::from_str("cp"),
             Err(ParseLanguageTagError::MissingMajorVersion {
                 implementation: "CPython",
                 tag: "cp".to_string()
             })
         );
         assert_eq!(
-            LanguageTag::parse("cpX"),
+            LanguageTag::from_str("cpX"),
             Err(ParseLanguageTagError::InvalidMajorVersion {
                 implementation: "CPython",
                 tag: "cpX".to_string()
             })
         );
         assert_eq!(
-            LanguageTag::parse("cp3X"),
+            LanguageTag::from_str("cp3X"),
             Err(ParseLanguageTagError::InvalidMinorVersion {
                 implementation: "CPython",
                 tag: "cp3X".to_string()
@@ -330,25 +320,25 @@ mod tests {
         let tag = LanguageTag::PyPy {
             python_version: (3, 9),
         };
-        assert_eq!(LanguageTag::parse("pp39").as_ref(), Ok(&tag));
+        assert_eq!(LanguageTag::from_str("pp39"), Ok(tag));
         assert_eq!(tag.to_string(), "pp39");
 
         assert_eq!(
-            LanguageTag::parse("pp"),
+            LanguageTag::from_str("pp"),
             Err(ParseLanguageTagError::MissingMajorVersion {
                 implementation: "PyPy",
                 tag: "pp".to_string()
             })
         );
         assert_eq!(
-            LanguageTag::parse("ppX"),
+            LanguageTag::from_str("ppX"),
             Err(ParseLanguageTagError::InvalidMajorVersion {
                 implementation: "PyPy",
                 tag: "ppX".to_string()
             })
         );
         assert_eq!(
-            LanguageTag::parse("pp3X"),
+            LanguageTag::from_str("pp3X"),
             Err(ParseLanguageTagError::InvalidMinorVersion {
                 implementation: "PyPy",
                 tag: "pp3X".to_string()
@@ -361,25 +351,25 @@ mod tests {
         let tag = LanguageTag::GraalPy {
             python_version: (3, 10),
         };
-        assert_eq!(LanguageTag::parse("graalpy310").as_ref(), Ok(&tag));
+        assert_eq!(LanguageTag::from_str("graalpy310"), Ok(tag));
         assert_eq!(tag.to_string(), "graalpy310");
 
         assert_eq!(
-            LanguageTag::parse("graalpy"),
+            LanguageTag::from_str("graalpy"),
             Err(ParseLanguageTagError::MissingMajorVersion {
                 implementation: "GraalPy",
                 tag: "graalpy".to_string()
             })
         );
         assert_eq!(
-            LanguageTag::parse("graalpyX"),
+            LanguageTag::from_str("graalpyX"),
             Err(ParseLanguageTagError::InvalidMajorVersion {
                 implementation: "GraalPy",
                 tag: "graalpyX".to_string()
             })
         );
         assert_eq!(
-            LanguageTag::parse("graalpy3X"),
+            LanguageTag::from_str("graalpy3X"),
             Err(ParseLanguageTagError::InvalidMinorVersion {
                 implementation: "GraalPy",
                 tag: "graalpy3X".to_string()
@@ -392,25 +382,25 @@ mod tests {
         let tag = LanguageTag::Pyston {
             python_version: (3, 8),
         };
-        assert_eq!(LanguageTag::parse("pyston38").as_ref(), Ok(&tag));
+        assert_eq!(LanguageTag::from_str("pyston38"), Ok(tag));
         assert_eq!(tag.to_string(), "pyston38");
 
         assert_eq!(
-            LanguageTag::parse("pyston"),
+            LanguageTag::from_str("pyston"),
             Err(ParseLanguageTagError::MissingMajorVersion {
                 implementation: "Pyston",
                 tag: "pyston".to_string()
             })
         );
         assert_eq!(
-            LanguageTag::parse("pystonX"),
+            LanguageTag::from_str("pystonX"),
             Err(ParseLanguageTagError::InvalidMajorVersion {
                 implementation: "Pyston",
                 tag: "pystonX".to_string()
             })
         );
         assert_eq!(
-            LanguageTag::parse("pyston3X"),
+            LanguageTag::from_str("pyston3X"),
             Err(ParseLanguageTagError::InvalidMinorVersion {
                 implementation: "Pyston",
                 tag: "pyston3X".to_string()
@@ -421,11 +411,11 @@ mod tests {
     #[test]
     fn unknown_language() {
         assert_eq!(
-            LanguageTag::parse("unknown"),
+            LanguageTag::from_str("unknown"),
             Err(ParseLanguageTagError::UnknownFormat("unknown".to_string()))
         );
         assert_eq!(
-            LanguageTag::parse(""),
+            LanguageTag::from_str(""),
             Err(ParseLanguageTagError::UnknownFormat(String::new()))
         );
     }

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

@@ -71,8 +71,6 @@ pub enum PlatformTag {
     Illumos { release_arch: SmallString },
     /// Ex) `solaris_11_4_x86_64`
     Solaris { release_arch: SmallString },
-    /// Ex) `win_ia64`
-    Unknown { tag: SmallString },
 }
 
 impl PlatformTag {
@@ -99,7 +97,6 @@ impl PlatformTag {
             PlatformTag::Haiku { .. } => Some("Haiku"),
             PlatformTag::Illumos { .. } => Some("Illumos"),
             PlatformTag::Solaris { .. } => Some("Solaris"),
-            PlatformTag::Unknown { .. } => None,
         }
     }
 }
@@ -265,14 +262,15 @@ impl std::fmt::Display for PlatformTag {
             Self::Haiku { release_arch } => write!(f, "haiku_{release_arch}"),
             Self::Illumos { release_arch } => write!(f, "illumos_{release_arch}"),
             Self::Solaris { release_arch } => write!(f, "solaris_{release_arch}_64bit"),
-            Self::Unknown { tag } => write!(f, "{tag}"),
         }
     }
 }
 
-impl PlatformTag {
+impl FromStr for PlatformTag {
+    type Err = ParsePlatformTagError;
+
     /// Parse a [`PlatformTag`] from a string.
-    fn parse(s: &str) -> Result<Self, ParsePlatformTagError> {
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
         // Match against any static variants.
         match s {
             "any" => return Ok(Self::Any),
@@ -622,14 +620,6 @@ impl PlatformTag {
     }
 }
 
-impl FromStr for PlatformTag {
-    type Err = ParsePlatformTagError;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        Ok(PlatformTag::parse(s).unwrap_or_else(|_| PlatformTag::Unknown { tag: s.into() }))
-    }
-}
-
 #[derive(Debug, thiserror::Error, PartialEq, Eq)]
 pub enum ParsePlatformTagError {
     #[error("Unknown platform tag format: {0}")]
@@ -648,13 +638,14 @@ pub enum ParsePlatformTagError {
 
 #[cfg(test)]
 mod tests {
+    use std::str::FromStr;
 
     use crate::platform_tag::{ParsePlatformTagError, PlatformTag};
     use crate::{Arch, BinaryFormat};
 
     #[test]
     fn any_platform() {
-        assert_eq!(PlatformTag::parse("any"), Ok(PlatformTag::Any));
+        assert_eq!(PlatformTag::from_str("any"), Ok(PlatformTag::Any));
         assert_eq!(PlatformTag::Any.to_string(), "any");
     }
 
@@ -666,13 +657,13 @@ mod tests {
             arch: Arch::X86_64,
         };
         assert_eq!(
-            PlatformTag::parse("manylinux_2_24_x86_64").as_ref(),
+            PlatformTag::from_str("manylinux_2_24_x86_64").as_ref(),
             Ok(&tag)
         );
         assert_eq!(tag.to_string(), "manylinux_2_24_x86_64");
 
         assert_eq!(
-            PlatformTag::parse("manylinux_x_24_x86_64"),
+            PlatformTag::from_str("manylinux_x_24_x86_64"),
             Err(ParsePlatformTagError::InvalidMajorVersion {
                 platform: "manylinux",
                 tag: "manylinux_x_24_x86_64".to_string()
@@ -680,7 +671,7 @@ mod tests {
         );
 
         assert_eq!(
-            PlatformTag::parse("manylinux_2_x_x86_64"),
+            PlatformTag::from_str("manylinux_2_x_x86_64"),
             Err(ParsePlatformTagError::InvalidMinorVersion {
                 platform: "manylinux",
                 tag: "manylinux_2_x_x86_64".to_string()
@@ -688,7 +679,7 @@ mod tests {
         );
 
         assert_eq!(
-            PlatformTag::parse("manylinux_2_24_invalid"),
+            PlatformTag::from_str("manylinux_2_24_invalid"),
             Err(ParsePlatformTagError::InvalidArch {
                 platform: "manylinux",
                 tag: "manylinux_2_24_invalid".to_string()
@@ -699,11 +690,14 @@ mod tests {
     #[test]
     fn manylinux1_platform() {
         let tag = PlatformTag::Manylinux1 { arch: Arch::X86_64 };
-        assert_eq!(PlatformTag::parse("manylinux1_x86_64").as_ref(), Ok(&tag));
+        assert_eq!(
+            PlatformTag::from_str("manylinux1_x86_64").as_ref(),
+            Ok(&tag)
+        );
         assert_eq!(tag.to_string(), "manylinux1_x86_64");
 
         assert_eq!(
-            PlatformTag::parse("manylinux1_invalid"),
+            PlatformTag::from_str("manylinux1_invalid"),
             Err(ParsePlatformTagError::InvalidArch {
                 platform: "manylinux1",
                 tag: "manylinux1_invalid".to_string()
@@ -715,13 +709,13 @@ mod tests {
     fn manylinux2010_platform() {
         let tag = PlatformTag::Manylinux2010 { arch: Arch::X86_64 };
         assert_eq!(
-            PlatformTag::parse("manylinux2010_x86_64").as_ref(),
+            PlatformTag::from_str("manylinux2010_x86_64").as_ref(),
             Ok(&tag)
         );
         assert_eq!(tag.to_string(), "manylinux2010_x86_64");
 
         assert_eq!(
-            PlatformTag::parse("manylinux2010_invalid"),
+            PlatformTag::from_str("manylinux2010_invalid"),
             Err(ParsePlatformTagError::InvalidArch {
                 platform: "manylinux2010",
                 tag: "manylinux2010_invalid".to_string()
@@ -733,13 +727,13 @@ mod tests {
     fn manylinux2014_platform() {
         let tag = PlatformTag::Manylinux2014 { arch: Arch::X86_64 };
         assert_eq!(
-            PlatformTag::parse("manylinux2014_x86_64").as_ref(),
+            PlatformTag::from_str("manylinux2014_x86_64").as_ref(),
             Ok(&tag)
         );
         assert_eq!(tag.to_string(), "manylinux2014_x86_64");
 
         assert_eq!(
-            PlatformTag::parse("manylinux2014_invalid"),
+            PlatformTag::from_str("manylinux2014_invalid"),
             Err(ParsePlatformTagError::InvalidArch {
                 platform: "manylinux2014",
                 tag: "manylinux2014_invalid".to_string()
@@ -750,11 +744,11 @@ mod tests {
     #[test]
     fn linux_platform() {
         let tag = PlatformTag::Linux { arch: Arch::X86_64 };
-        assert_eq!(PlatformTag::parse("linux_x86_64").as_ref(), Ok(&tag));
+        assert_eq!(PlatformTag::from_str("linux_x86_64").as_ref(), Ok(&tag));
         assert_eq!(tag.to_string(), "linux_x86_64");
 
         assert_eq!(
-            PlatformTag::parse("linux_invalid"),
+            PlatformTag::from_str("linux_invalid"),
             Err(ParsePlatformTagError::InvalidArch {
                 platform: "linux",
                 tag: "linux_invalid".to_string()
@@ -770,13 +764,13 @@ mod tests {
             arch: Arch::X86_64,
         };
         assert_eq!(
-            PlatformTag::parse("musllinux_1_2_x86_64").as_ref(),
+            PlatformTag::from_str("musllinux_1_2_x86_64").as_ref(),
             Ok(&tag)
         );
         assert_eq!(tag.to_string(), "musllinux_1_2_x86_64");
 
         assert_eq!(
-            PlatformTag::parse("musllinux_x_2_x86_64"),
+            PlatformTag::from_str("musllinux_x_2_x86_64"),
             Err(ParsePlatformTagError::InvalidMajorVersion {
                 platform: "musllinux",
                 tag: "musllinux_x_2_x86_64".to_string()
@@ -784,7 +778,7 @@ mod tests {
         );
 
         assert_eq!(
-            PlatformTag::parse("musllinux_1_x_x86_64"),
+            PlatformTag::from_str("musllinux_1_x_x86_64"),
             Err(ParsePlatformTagError::InvalidMinorVersion {
                 platform: "musllinux",
                 tag: "musllinux_1_x_x86_64".to_string()
@@ -792,7 +786,7 @@ mod tests {
         );
 
         assert_eq!(
-            PlatformTag::parse("musllinux_1_2_invalid"),
+            PlatformTag::from_str("musllinux_1_2_invalid"),
             Err(ParsePlatformTagError::InvalidArch {
                 platform: "musllinux",
                 tag: "musllinux_1_2_invalid".to_string()
@@ -808,13 +802,13 @@ mod tests {
             binary_format: BinaryFormat::Universal2,
         };
         assert_eq!(
-            PlatformTag::parse("macosx_11_0_universal2").as_ref(),
+            PlatformTag::from_str("macosx_11_0_universal2").as_ref(),
             Ok(&tag)
         );
         assert_eq!(tag.to_string(), "macosx_11_0_universal2");
 
         assert_eq!(
-            PlatformTag::parse("macosx_x_0_universal2"),
+            PlatformTag::from_str("macosx_x_0_universal2"),
             Err(ParsePlatformTagError::InvalidMajorVersion {
                 platform: "macosx",
                 tag: "macosx_x_0_universal2".to_string()
@@ -822,7 +816,7 @@ mod tests {
         );
 
         assert_eq!(
-            PlatformTag::parse("macosx_11_x_universal2"),
+            PlatformTag::from_str("macosx_11_x_universal2"),
             Err(ParsePlatformTagError::InvalidMinorVersion {
                 platform: "macosx",
                 tag: "macosx_11_x_universal2".to_string()
@@ -830,7 +824,7 @@ mod tests {
         );
 
         assert_eq!(
-            PlatformTag::parse("macosx_11_0_invalid"),
+            PlatformTag::from_str("macosx_11_0_invalid"),
             Err(ParsePlatformTagError::InvalidArch {
                 platform: "macosx",
                 tag: "macosx_11_0_invalid".to_string()
@@ -840,19 +834,25 @@ mod tests {
 
     #[test]
     fn win32_platform() {
-        assert_eq!(PlatformTag::parse("win32"), Ok(PlatformTag::Win32));
+        assert_eq!(PlatformTag::from_str("win32"), Ok(PlatformTag::Win32));
         assert_eq!(PlatformTag::Win32.to_string(), "win32");
     }
 
     #[test]
     fn win_amd64_platform() {
-        assert_eq!(PlatformTag::parse("win_amd64"), Ok(PlatformTag::WinAmd64));
+        assert_eq!(
+            PlatformTag::from_str("win_amd64"),
+            Ok(PlatformTag::WinAmd64)
+        );
         assert_eq!(PlatformTag::WinAmd64.to_string(), "win_amd64");
     }
 
     #[test]
     fn win_arm64_platform() {
-        assert_eq!(PlatformTag::parse("win_arm64"), Ok(PlatformTag::WinArm64));
+        assert_eq!(
+            PlatformTag::from_str("win_arm64"),
+            Ok(PlatformTag::WinArm64)
+        );
         assert_eq!(PlatformTag::WinArm64.to_string(), "win_arm64");
     }
 
@@ -862,7 +862,7 @@ mod tests {
             release_arch: "13_14_x86_64".into(),
         };
         assert_eq!(
-            PlatformTag::parse("freebsd_13_14_x86_64").as_ref(),
+            PlatformTag::from_str("freebsd_13_14_x86_64").as_ref(),
             Ok(&tag)
         );
         assert_eq!(tag.to_string(), "freebsd_13_14_x86_64");
@@ -873,7 +873,10 @@ mod tests {
         let tag = PlatformTag::Illumos {
             release_arch: "5_11_x86_64".into(),
         };
-        assert_eq!(PlatformTag::parse("illumos_5_11_x86_64").as_ref(), Ok(&tag));
+        assert_eq!(
+            PlatformTag::from_str("illumos_5_11_x86_64").as_ref(),
+            Ok(&tag)
+        );
         assert_eq!(tag.to_string(), "illumos_5_11_x86_64");
     }
 
@@ -883,13 +886,13 @@ mod tests {
             release_arch: "11_4_x86_64".into(),
         };
         assert_eq!(
-            PlatformTag::parse("solaris_11_4_x86_64_64bit").as_ref(),
+            PlatformTag::from_str("solaris_11_4_x86_64_64bit").as_ref(),
             Ok(&tag)
         );
         assert_eq!(tag.to_string(), "solaris_11_4_x86_64_64bit");
 
         assert_eq!(
-            PlatformTag::parse("solaris_11_4_x86_64"),
+            PlatformTag::from_str("solaris_11_4_x86_64"),
             Err(ParsePlatformTagError::InvalidArch {
                 platform: "solaris",
                 tag: "solaris_11_4_x86_64".to_string()
@@ -900,11 +903,11 @@ mod tests {
     #[test]
     fn unknown_platform() {
         assert_eq!(
-            PlatformTag::parse("unknown"),
+            PlatformTag::from_str("unknown"),
             Err(ParsePlatformTagError::UnknownFormat("unknown".to_string()))
         );
         assert_eq!(
-            PlatformTag::parse(""),
+            PlatformTag::from_str(""),
             Err(ParsePlatformTagError::UnknownFormat(String::new()))
         );
     }

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

@@ -298,13 +298,13 @@ impl Tags {
     }
 
     /// Return the highest-priority Python tag for the [`Tags`].
-    pub fn python_tag(&self) -> Option<&LanguageTag> {
+    pub fn python_tag(&self) -> Option<LanguageTag> {
-        self.best.as_ref().map(|(python, _, _)| python)
+        self.best.as_ref().map(|(python, _, _)| *python)
     }
 
     /// Return the highest-priority ABI tag for the [`Tags`].
-    pub fn abi_tag(&self) -> Option<&AbiTag> {
+    pub fn abi_tag(&self) -> Option<AbiTag> {
-        self.best.as_ref().map(|(_, abi, _)| abi)
+        self.best.as_ref().map(|(_, abi, _)| *abi)
     }
 
     /// Return the highest-priority platform tag for the [`Tags`].
@@ -314,10 +314,10 @@ impl Tags {
 
     /// Returns `true` if the given language and ABI tags are compatible with the current
     /// environment.
-    pub fn is_compatible_abi(&self, python_tag: &LanguageTag, abi_tag: &AbiTag) -> bool {
+    pub fn is_compatible_abi(&self, python_tag: LanguageTag, abi_tag: AbiTag) -> bool {
         self.map
-            .get(python_tag)
+            .get(&python_tag)
-            .map(|abis| abis.contains_key(abi_tag))
+            .map(|abis| abis.contains_key(&abi_tag))
             .unwrap_or(false)
     }
 }

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

@@ -744,12 +744,8 @@ impl PubGrubReportFormatter<'_> {
         match tag {
             IncompatibleTag::Invalid => None,
             IncompatibleTag::Python => {
-                let best = tags.and_then(Tags::python_tag).cloned();
+                let best = tags.and_then(Tags::python_tag);
-                let tags = prioritized
+                let tags = prioritized.python_tags();
-                    .python_tags()
-                    .into_iter()
-                    .cloned()
-                    .collect::<BTreeSet<_>>();
                 if tags.is_empty() {
                     None
                 } else {
@@ -762,7 +758,7 @@ impl PubGrubReportFormatter<'_> {
                 }
             }
             IncompatibleTag::Abi | IncompatibleTag::AbiPythonVersion => {
-                let best = tags.and_then(Tags::abi_tag).cloned();
+                let best = tags.and_then(Tags::abi_tag);
                 let tags = prioritized
                     .abi_tags()
                     .into_iter()
@@ -774,8 +770,7 @@ impl PubGrubReportFormatter<'_> {
                     // In that case, the wheel isn't compatible, but when solving for Python 3.13,
                     // the `cp312` Python tag _can_ be compatible (e.g., for `cp312-abi3-macosx_11_0_arm64.whl`),
                     // so this is considered an ABI incompatibility rather than Python incompatibility.
-                    .filter(|tag| **tag != AbiTag::None)
+                    .filter(|tag| *tag != AbiTag::None)
-                    .cloned()
                     .collect::<BTreeSet<_>>();
                 if tags.is_empty() {
                     None
@@ -1581,7 +1576,7 @@ impl std::fmt::Display for PubGrubHint {
                 tags,
                 best,
             } => {
-                if let Some(best) = best.as_ref() {
+                if let Some(best) = best {
                     let s = if tags.len() == 1 { "" } else { "s" };
                     let best = if let Some(pretty) = best.pretty() {
                         format!("{} (`{}`)", pretty.cyan(), best.cyan())
@@ -1621,7 +1616,7 @@ impl std::fmt::Display for PubGrubHint {
                 tags,
                 best,
             } => {
-                if let Some(best) = best.as_ref() {
+                if let Some(best) = best {
                     let s = if tags.len() == 1 { "" } else { "s" };
                     let best = if let Some(pretty) = best.pretty() {
                         format!("{} (`{}`)", pretty.cyan(), best.cyan())