test(self-update): ensure the resolution of #3739

tests/suite/cli_self_upd.rs

@@ -304,7 +304,39 @@ info: downloading self-update
             &["rustup", "self", "update"],
             &format!("  rustup updated - {version} (from {version})\n\n",),
             &expected_output,
-        )
+        );
+    });
+}
+
+#[test]
+#[cfg(windows)]
+fn update_overwrites_programs_display_version() {
+    const RUSTUP_UNINSTALL_ENTRY: &str =
+        r"Software\Microsoft\Windows\CurrentVersion\Uninstall\Rustup";
+
+    const PLACEHOLDER_VERSION: &str = "9.999.99";
+    let version = env!("CARGO_PKG_VERSION");
+
+    update_setup(&|config, _| {
+        config.expect_ok(&["rustup-init", "-y", "--no-modify-path"]);
+
+        winreg::RegKey::predef(winreg::enums::HKEY_CURRENT_USER)
+            .create_subkey(RUSTUP_UNINSTALL_ENTRY)
+            .unwrap()
+            .0
+            .set_value("DisplayVersion", PLACEHOLDER_VERSION)
+            .unwrap();
+
+        config.expect_ok(&["rustup", "self", "update"]);
+
+        assert_eq!(
+            winreg::RegKey::predef(winreg::enums::HKEY_CURRENT_USER)
+                .open_subkey(RUSTUP_UNINSTALL_ENTRY)
+                .unwrap()
+                .get_value::<String, _>("DisplayVersion")
+                .unwrap(),
+            version,
+        );
     });
 }