Avoid allocating static ABI descriptions

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

@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::fmt::{Display, Formatter, Write};
 use std::ops::{Deref, DerefMut};
 use std::str::FromStr;
@@ -136,11 +137,11 @@ impl AbiTag {
     }
 
     /// Return a pretty string representation of the ABI tag.
-    pub fn pretty(self) -> Option<String> {
+    pub fn pretty(self) -> Option<Cow<'static, str>> {
         match self {
             Self::None => None,
             Self::Abi3 => None,
-            Self::Abi3T => Some("stable ABI for free-threaded CPython".to_string()),
+            Self::Abi3T => Some(Cow::Borrowed("stable ABI for free-threaded CPython")),
             Self::CPython {
                 variant,
                 python_version,
@@ -156,26 +157,26 @@ impl AbiTag {
                 } else {
                     ""
                 };
-                Some(format!(
+                Some(Cow::Owned(format!(
                     "{}CPython {}.{}",
                     prefix, python_version.0, python_version.1
-                ))
+                )))
             }
             Self::PyPy {
                 implementation_version,
                 ..
-            } => Some(format!(
+            } => Some(Cow::Owned(format!(
                 "PyPy {}.{}",
                 implementation_version.0, implementation_version.1
-            )),
+            ))),
             Self::GraalPy {
                 implementation_version,
                 ..
-            } => Some(format!(
+            } => Some(Cow::Owned(format!(
                 "GraalPy {}.{}",
                 implementation_version.0, implementation_version.1
-            )),
-            Self::Pyston { .. } => Some("Pyston".to_string()),
+            ))),
+            Self::Pyston { .. } => Some(Cow::Borrowed("Pyston")),
         }
     }
 }
@@ -489,24 +490,24 @@ mod tests {
         assert_eq!(AbiTag::Abi3T.to_string(), "abi3t");
         assert!(AbiTag::Abi3T.is_stable_abi());
         assert_eq!(
-            AbiTag::Abi3T.pretty(),
-            Some("stable ABI for free-threaded CPython".to_string())
+            AbiTag::Abi3T.pretty().as_deref(),
+            Some("stable ABI for free-threaded CPython")
         );
     }
 
     #[test]
     fn cpython_abi() {
         let tag = AbiTag::from_str("cp39").unwrap();
         assert_eq!(tag.to_string(), "cp39");
-        assert_eq!(tag.pretty(), Some("CPython 3.9".to_string()));
+        assert_eq!(tag.pretty().as_deref(), Some("CPython 3.9"));
 
         let tag = AbiTag::from_str("cp37m").unwrap();
         assert_eq!(tag.to_string(), "cp37m");
-        assert_eq!(tag.pretty(), Some("CPython 3.7".to_string()));
+        assert_eq!(tag.pretty().as_deref(), Some("CPython 3.7"));
 
         let tag = AbiTag::from_str("cp313t").unwrap();
         assert_eq!(tag.to_string(), "cp313t");
-        assert_eq!(tag.pretty(), Some("free-threaded CPython 3.13".to_string()));
+        assert_eq!(tag.pretty().as_deref(), Some("free-threaded CPython 3.13"));
 
         assert_eq!(
             AbiTag::from_str("cpXY"),