Fix uv python install --reinstall when the version is not yet installed (#12124)

I noticed this was failing to perform the install

Author: zanieb

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

@@ -205,15 +205,17 @@ pub(crate) async fn install(
             Vec::with_capacity(existing_installations.len() + requests.len());
 
         for request in &requests {
-            if existing_installations.is_empty() {
+            let mut matching_installations = existing_installations
+                .iter()
+                .filter(|installation| request.matches_installation(installation))
+                .peekable();
+
+            if matching_installations.peek().is_none() {
                 debug!("No installation found for request `{}`", request.cyan());
                 unsatisfied.push(Cow::Borrowed(request));
             }
 
-            for installation in existing_installations
-                .iter()
-                .filter(|installation| request.matches_installation(installation))
-            {
+            for installation in matching_installations {
                 changelog.existing.insert(installation.key().clone());
                 if matches!(&request.request, &PythonRequest::Any) {
                     // Construct a install request matching the existing installation
@@ -300,6 +302,7 @@ pub(crate) async fn install(
         .build();
     let reporter = PythonDownloadReporter::new(printer, downloads.len() as u64);
     let mut tasks = FuturesUnordered::new();
+
     for download in &downloads {
         tasks.push(async {
             (

crates/uv/tests/it/python_install.rs

@@ -99,7 +99,7 @@ fn python_reinstall() {
         .with_managed_python_dirs();
 
     // Install a couple versions
-    uv_snapshot!(context.filters(), context.python_install().arg("3.12").arg("3.13"), @r###"
+    uv_snapshot!(context.filters(), context.python_install().arg("3.12").arg("3.13"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
@@ -108,21 +108,21 @@ fn python_reinstall() {
     Installed 2 versions in [TIME]
      + cpython-3.12.9-[PLATFORM]
      + cpython-3.13.2-[PLATFORM]
-    "###);
+    ");
 
     // Reinstall a single version
-    uv_snapshot!(context.filters(), context.python_install().arg("3.13").arg("--reinstall"), @r###"
+    uv_snapshot!(context.filters(), context.python_install().arg("3.13").arg("--reinstall"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
 
     ----- stderr -----
     Installed Python 3.13.2 in [TIME]
      ~ cpython-3.13.2-[PLATFORM]
-    "###);
+    ");
 
     // Reinstall multiple versions
-    uv_snapshot!(context.filters(), context.python_install().arg("--reinstall"), @r###"
+    uv_snapshot!(context.filters(), context.python_install().arg("--reinstall"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
@@ -131,7 +131,18 @@ fn python_reinstall() {
     Installed 2 versions in [TIME]
      ~ cpython-3.12.9-[PLATFORM]
      ~ cpython-3.13.2-[PLATFORM]
-    "###);
+    ");
+
+    // Reinstalling a version that is not installed should also work
+    uv_snapshot!(context.filters(), context.python_install().arg("3.11").arg("--reinstall"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Installed Python 3.11.11 in [TIME]
+     + cpython-3.11.11-[PLATFORM]
+    ");
 }
 
 #[test]
@@ -142,7 +153,7 @@ fn python_reinstall_patch() {
         .with_managed_python_dirs();
 
     // Install a couple patch versions
-    uv_snapshot!(context.filters(), context.python_install().arg("3.12.6").arg("3.12.7"), @r###"
+    uv_snapshot!(context.filters(), context.python_install().arg("3.12.6").arg("3.12.7"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
@@ -151,20 +162,20 @@ fn python_reinstall_patch() {
     Installed 2 versions in [TIME]
      + cpython-3.12.6-[PLATFORM]
      + cpython-3.12.7-[PLATFORM]
-    "###);
+    ");
 
     // Reinstall all "3.12" versions
     // TODO(zanieb): This doesn't work today, because we need this to install the "latest" as there
     // is no workflow for `--upgrade` yet
-    uv_snapshot!(context.filters(), context.python_install().arg("3.12").arg("--reinstall"), @r###"
+    uv_snapshot!(context.filters(), context.python_install().arg("3.12").arg("--reinstall"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
 
     ----- stderr -----
     Installed Python 3.12.9 in [TIME]
      + cpython-3.12.9-[PLATFORM]
-    "###);
+    ");
 }
 
 #[test]