Ban pre-release versions in uv python upgrade requests (#16160)

crates/uv-python/src/discovery.rs

@@ -1945,6 +1945,24 @@ impl PythonRequest {
         }
     }
 
+    /// Check if this request includes a specific prerelease version.
+    pub fn includes_prerelease(&self) -> bool {
+        match self {
+            Self::Default => false,
+            Self::Any => false,
+            Self::Version(version_request) => version_request.prerelease().is_some(),
+            Self::Directory(..) => false,
+            Self::File(..) => false,
+            Self::ExecutableName(..) => false,
+            Self::Implementation(..) => false,
+            Self::ImplementationVersion(_, version) => version.prerelease().is_some(),
+            Self::Key(request) => request
+                .version
+                .as_ref()
+                .is_some_and(|request| request.prerelease().is_some()),
+        }
+    }
+
     /// Check if a given interpreter satisfies the interpreter request.
     pub fn satisfied(&self, interpreter: &Interpreter, cache: &Cache) -> bool {
         /// Returns `true` if the two paths refer to the same interpreter executable.
@@ -2565,6 +2583,17 @@ impl VersionRequest {
         }
     }
 
+    /// Return the pre-release segment of the request, if any.
+    pub(crate) fn prerelease(&self) -> Option<&Prerelease> {
+        match self {
+            Self::Any | Self::Default | Self::Range(_, _) => None,
+            Self::Major(_, _) => None,
+            Self::MajorMinor(_, _, _) => None,
+            Self::MajorMinorPatch(_, _, _, _) => None,
+            Self::MajorMinorPrerelease(_, _, prerelease, _) => Some(prerelease),
+        }
+    }
+
     /// Check if the request is for a version supported by uv.
     ///
     /// If not, an `Err` is returned with an explanatory message.

crates/uv/src/commands/python/install.rs

@@ -285,9 +285,9 @@ pub(crate) async fn install(
         .collect::<IndexSet<_>>();
 
     if upgrade
-        && requests
-            .iter()
-            .any(|request| request.request.includes_patch())
+        && requests.iter().any(|request| {
+            request.request.includes_patch() || request.request.includes_prerelease()
+        })
     {
         writeln!(
             printer.stderr(),

crates/uv/tests/it/python_install.rs

@@ -1216,6 +1216,34 @@ fn python_install_freethreaded() {
     ");
 }
 
+#[test]
+fn python_upgrade_not_allowed() {
+    let context: TestContext = TestContext::new_with_versions(&[])
+        .with_filtered_python_keys()
+        .with_filtered_exe_suffix()
+        .with_managed_python_dirs();
+
+    // Request a patch upgrade
+    uv_snapshot!(context.filters(), context.python_upgrade().arg("--preview").arg("3.13.0"), @r"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+
+    ----- stderr -----
+    error: `uv python upgrade` only accepts minor versions
+    ");
+
+    // Request a pre-release upgrade
+    uv_snapshot!(context.filters(), context.python_upgrade().arg("--preview").arg("3.14rc3"), @r"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+
+    ----- stderr -----
+    error: `uv python upgrade` only accepts minor versions
+    ");
+}
+
 // We only support debug builds on Unix
 #[cfg(unix)]
 #[test]