Enable --all to uninstall all managed Pythons (#4932)

## Summary

Allows `--all` as an alternative to specifying specific targets.

## Test Plan

Verified that `cargo run python uninstall` still fails.

```
❯ cargo run python uninstall --all
   Compiling uv-cli v0.0.1 (/Users/crmarsh/workspace/puffin/crates/uv-cli)
   Compiling uv v0.2.23 (/Users/crmarsh/workspace/puffin/crates/uv)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.86s
     Running `target/debug/uv python uninstall --all`
warning: `uv python uninstall` is experimental and may change without warning.
Searching for Python installations
Found existing installation: cpython-3.9.18-macos-aarch64-none
Found existing installation: cpython-3.8.18-macos-aarch64-none
Found existing installation: cpython-3.8.12-macos-aarch64-none
Found existing installation: cpython-3.12.1-macos-aarch64-none
Found existing installation: cpython-3.11.7-macos-aarch64-none
Found existing installation: cpython-3.10.13-macos-aarch64-none
Uninstalled cpython-3.10.13-macos-aarch64-none
Uninstalled cpython-3.11.7-macos-aarch64-none
Uninstalled cpython-3.12.1-macos-aarch64-none
Uninstalled cpython-3.8.12-macos-aarch64-none
Uninstalled cpython-3.8.18-macos-aarch64-none
Uninstalled cpython-3.9.18-macos-aarch64-none
Uninstalled 6 versions in 479ms
```

crates/uv-cli/src/lib.rs

@@ -2198,6 +2198,10 @@ pub struct PythonUninstallArgs {
     /// The Python version(s) to uninstall.
     #[arg(required = true)]
     pub targets: Vec<String>,
+
+    /// Uninstall all managed Python versions.
+    #[arg(long, conflicts_with("targets"))]
+    pub all: bool,
 }
 
 #[derive(Args)]

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

@@ -18,6 +18,7 @@ use crate::printer::Printer;
 /// Uninstall managed Python versions.
 pub(crate) async fn uninstall(
     targets: Vec<String>,
+    all: bool,
     preview: PreviewMode,
     printer: Printer,
 ) -> Result<ExitStatus> {
@@ -30,11 +31,15 @@ pub(crate) async fn uninstall(
     let installations = ManagedPythonInstallations::from_settings()?.init()?;
     let _lock = installations.acquire_lock()?;
 
-    let targets = targets.into_iter().collect::<BTreeSet<_>>();
-    let requests = targets
-        .iter()
-        .map(|target| PythonRequest::parse(target.as_str()))
-        .collect::<Vec<_>>();
+    let requests = if all {
+        vec![PythonRequest::Any]
+    } else {
+        let targets = targets.into_iter().collect::<BTreeSet<_>>();
+        targets
+            .iter()
+            .map(|target| PythonRequest::parse(target.as_str()))
+            .collect::<Vec<_>>()
+    };
 
     let download_requests = requests
         .iter()
@@ -44,11 +49,15 @@ pub(crate) async fn uninstall(
     let installed_installations: Vec<_> = installations.find_all()?.collect();
     let mut matching_installations = BTreeSet::default();
     for (request, download_request) in requests.iter().zip(download_requests) {
-        writeln!(
-            printer.stderr(),
-            "Searching for Python versions matching: {}",
-            request.cyan()
-        )?;
+        if matches!(requests.as_slice(), [PythonRequest::Any]) {
+            writeln!(printer.stderr(), "Searching for Python installations")?;
+        } else {
+            writeln!(
+                printer.stderr(),
+                "Searching for Python versions matching: {}",
+                request.cyan()
+            )?;
+        }
         let mut found = false;
         for installation in installed_installations
             .iter()
@@ -56,15 +65,24 @@ pub(crate) async fn uninstall(
         {
             found = true;
             if matching_installations.insert(installation.clone()) {
-                writeln!(
-                    printer.stderr(),
-                    "Found existing installation for {}: {}",
-                    request.cyan(),
-                    installation.key().green(),
-                )?;
+                if matches!(requests.as_slice(), [PythonRequest::Any]) {
+                    writeln!(printer.stderr(), "Found: {}", installation.key().green(),)?;
+                } else {
+                    writeln!(
+                        printer.stderr(),
+                        "Found existing installation for {}: {}",
+                        request.cyan(),
+                        installation.key().green(),
+                    )?;
+                }
             }
         }
         if !found {
+            if matches!(requests.as_slice(), [PythonRequest::Any]) {
+                writeln!(printer.stderr(), "No Python installations found")?;
+                return Ok(ExitStatus::Failure);
+            }
+
             writeln!(
                 printer.stderr(),
                 "No existing installations found for: {}",
@@ -74,14 +92,10 @@ pub(crate) async fn uninstall(
     }
 
     if matching_installations.is_empty() {
-        if matches!(requests.as_slice(), [PythonRequest::Any]) {
-            writeln!(printer.stderr(), "No Python installations found")?;
-        } else if requests.len() > 1 {
-            writeln!(
-                printer.stderr(),
-                "No Python installations found matching the requests"
-            )?;
-        }
+        writeln!(
+            printer.stderr(),
+            "No Python installations found matching the requests"
+        )?;
         return Ok(ExitStatus::Failure);
     }
 
@@ -105,7 +119,7 @@ pub(crate) async fn uninstall(
                 key.green()
             )?;
         } else {
-            writeln!(printer.stderr(), "Uninstalled {}", key.green())?;
+            writeln!(printer.stderr(), "Uninstalled: {}", key.green())?;
         }
     }
 

crates/uv/src/main.rs

@@ -788,7 +788,7 @@ async fn run() -> Result<ExitStatus> {
             let args = settings::PythonUninstallSettings::resolve(args, filesystem);
             show_settings!(args);
 
-            commands::python_uninstall(args.targets, globals.preview, printer).await
+            commands::python_uninstall(args.targets, args.all, globals.preview, printer).await
         }
         Commands::Python(PythonNamespace {
             command: PythonCommand::Find(args),

crates/uv/src/settings.rs

@@ -376,6 +376,7 @@ impl PythonInstallSettings {
 #[derive(Debug, Clone)]
 pub(crate) struct PythonUninstallSettings {
     pub(crate) targets: Vec<String>,
+    pub(crate) all: bool,
 }
 
 impl PythonUninstallSettings {
@@ -385,9 +386,9 @@ impl PythonUninstallSettings {
         args: PythonUninstallArgs,
         _filesystem: Option<FilesystemOptions>,
     ) -> Self {
-        let PythonUninstallArgs { targets } = args;
+        let PythonUninstallArgs { targets, all } = args;
 
-        Self { targets }
+        Self { targets, all }
     }
 }