test(cli_v2): introduce update_removed_component_toolchain()

src/test/mock/clitools.rs

@@ -93,6 +93,8 @@ pub enum Scenario {
     Unavailable,
     /// Two dates, v2 manifests, RLS unavailable in first date, restored on second.
     UnavailableRls,
+    /// Two dates, v2 manifests, RLS available in first stable, removed on second.
+    RemovedRls,
     /// Three dates, v2 manifests, RLS available in first and second, not last
     MissingComponent,
     /// Three dates, v2 manifests, RLS available in first, middle missing nightly
@@ -152,6 +154,7 @@ impl ConstState {
                 Scenario::MissingNightly => RwLock::new(None),
                 Scenario::MultiHost => RwLock::new(None),
                 Scenario::None => RwLock::new(None),
+                Scenario::RemovedRls => RwLock::new(None),
                 Scenario::SimpleV1 => RwLock::new(None),
                 Scenario::SimpleV2 => RwLock::new(None),
                 Scenario::Unavailable => RwLock::new(None),
@@ -1152,6 +1155,10 @@ fn create_mock_dist_server(path: &Path, s: Scenario) {
                 Release::stable("1.1.0", "2015-01-02"),
             ]
         }
+        Scenario::RemovedRls => vec![
+            Release::stable("1.78.0", "2024-05-01"),
+            Release::stable("1.79.0", "2024-06-15").with_rls(RlsStatus::Unavailable),
+        ],
         Scenario::SimpleV1 | Scenario::SimpleV2 => vec![
             Release::new("nightly", "1.3.0", "2015-01-02", "2").with_rls(RlsStatus::Renamed),
             Release::beta("1.2.0", "2015-01-02"),
@@ -1199,6 +1206,7 @@ fn create_mock_dist_server(path: &Path, s: Scenario) {
         | Scenario::MultiHost
         | Scenario::Unavailable
         | Scenario::UnavailableRls
+        | Scenario::RemovedRls
         | Scenario::MissingNightly
         | Scenario::HostGoesMissingBefore
         | Scenario::HostGoesMissingAfter

tests/suite/cli_v2.rs

@@ -1378,6 +1378,50 @@ Then you can use the toolchain with commands such as:
     ).await;
 }
 
+#[tokio::test]
+async fn update_removed_component_toolchain() {
+    let mut cx = CliTestContext::new(Scenario::RemovedRls).await;
+    set_current_dist_date(&cx.config, "2024-05-01");
+    cx.config.expect_ok(&["rustup", "default", "stable"]).await;
+
+    // Install `rls` on the first day.
+    cx.config
+        .expect_stdout_ok(&["rustc", "--version"], "1.78.0")
+        .await;
+    cx.config
+        .expect_ok(&["rustup", "component", "add", "rls"])
+        .await;
+    cx.config.expect_component_executable("rls").await;
+
+    // `rls` is missing on the second day.
+    set_current_dist_date(&cx.config, "2024-06-15");
+
+    // An update at this time should inform the user of an unavailable component.
+    cx.config
+        .expect_err(
+            &["rustup", "update", "stable"],
+            for_host!(
+                r"component 'rls' for target '{0}' is unavailable for download for channel 'stable'
+One or many components listed above might have been permanently removed from newer versions
+of the official Rust distribution due to deprecation.
+
+If you are updating an existing toolchain, after determining the deprecated component(s)
+in question, please remove them with a command such as:
+
+    rustup component remove --toolchain stable <COMPONENT>...
+
+After that, you should be able to continue with the update as usual."
+            ),
+        )
+        .await;
+
+    // We're still stuck with the old version.
+    cx.config
+        .expect_stdout_ok(&["rustc", "--version"], "1.78.0")
+        .await;
+    cx.config.expect_component_executable("rls").await;
+}
+
 #[tokio::test]
 async fn update_unavailable_force() {
     let mut cx = CliTestContext::new(Scenario::SimpleV2).await;