Improve Python uninstall perf by removing unnecessary call to installations.find_all() (#14180)

#13954 introduced an unnecessary slow-down to Python uninstall by
calling `installations.find_all()` to discover remaining installations
after an uninstall. Instead, we can filter all initial installations
against those in `uninstalled`.

As part of this change, I've updated `uninstalled` from a `Vec` to an
`IndexSet` in order to do efficient lookups in the filter. This required
a change I call out below to how we were retrieving them for messaging.

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

@@ -200,13 +200,13 @@ async fn do_uninstall(
         });
     }
 
-    let mut uninstalled = vec![];
+    let mut uninstalled = IndexSet::<PythonInstallationKey>::default();
     let mut errors = vec![];
     while let Some((key, result)) = tasks.next().await {
         if let Err(err) = result {
             errors.push((key.clone(), anyhow::Error::new(err)));
         } else {
-            uninstalled.push(key.clone());
+            uninstalled.insert(key.clone());
         }
     }
 
@@ -223,14 +223,15 @@ async fn do_uninstall(
     // Read all existing managed installations and find the highest installed patch
     // for each installed minor version. Ensure the minor version link directory
     // is still valid.
-    let uninstalled_minor_versions = &uninstalled.iter().fold(
-        IndexSet::<&PythonInstallationMinorVersionKey>::default(),
-        |mut minor_versions, key| {
-            minor_versions.insert(PythonInstallationMinorVersionKey::ref_cast(key));
-            minor_versions
-        },
-    );
-    let remaining_installations: Vec<_> = installations.find_all()?.collect();
+    let uninstalled_minor_versions: IndexSet<_> = uninstalled
+        .iter()
+        .map(PythonInstallationMinorVersionKey::ref_cast)
+        .collect();
+    let remaining_installations: Vec<_> = installed_installations
+        .into_iter()
+        .filter(|installation| !uninstalled.contains(installation.key()))
+        .collect();
+
     let remaining_minor_versions =
         PythonInstallationMinorVersionKey::highest_installations_by_minor_version_key(
             remaining_installations.iter(),
@@ -278,28 +279,27 @@ async fn do_uninstall(
     }
 
     // Report on any uninstalled installations.
-    if !uninstalled.is_empty() {
-        if let [uninstalled] = uninstalled.as_slice() {
+    if let Some(first_uninstalled) = uninstalled.first() {
+        if uninstalled.len() == 1 {
             // Ex) "Uninstalled Python 3.9.7 in 1.68s"
             writeln!(
                 printer.stderr(),
                 "{}",
                 format!(
                     "Uninstalled {} {}",
-                    format!("Python {}", uninstalled.version()).bold(),
+                    format!("Python {}", first_uninstalled.version()).bold(),
                     format!("in {}", elapsed(start.elapsed())).dimmed()
                 )
                 .dimmed()
             )?;
         } else {
             // Ex) "Uninstalled 2 versions in 1.68s"
-            let s = if uninstalled.len() == 1 { "" } else { "s" };
             writeln!(
                 printer.stderr(),
                 "{}",
                 format!(
                     "Uninstalled {} {}",
-                    format!("{} version{s}", uninstalled.len()).bold(),
+                    format!("{} versions", uninstalled.len()).bold(),
                     format!("in {}", elapsed(start.elapsed())).dimmed()
                 )
                 .dimmed()