feat(rust): adapt to zbus 5 (agama-project#1716)

## The main goal

Although [zbus 5](https://github.com/dbus2/zbus/releases/tag/zbus-5.0.0)
5 was released a few days ago, Agama is still using zbus 3. The goal of
this PR is to adapt the code to use the latest version.

However, this task is not trivial: version 4 already introduced a good
share of breaking changes in zbus API.

## `downcast_ref` returns `Result`

The `downcast_ref` function now returns a `Result` instead of an
`Option` with, IMHO, it is the right thing to do. This change has a big
impact in our code to interact with NetworkManager, so I took the
opportunity to:

* Distinguish between a problem and a missing value (we always returned
`None` when something went wrong).
* Use `get_property` and `get_optional_property` to simplify our code a
bit.

## Other changes

- Do some refactoring and organization of D-Bus proxies.
- Improve the `network::nm::dbus` module. Let's use `get_property` and
`get_optional_property` for better readability and error handling.
Please, check [this commit
(WIP)](agama-project@c21eda8)
if you are interested in further improvements.
- Drop some unused code.

rust/agama-cli/src/questions.rs

@@ -18,7 +18,7 @@
 // To contact SUSE LLC about this file by physical or electronic mail, you may
 // find current contact information at www.suse.com.
 
-use agama_lib::proxies::Questions1Proxy;
+use agama_lib::proxies::questions::QuestionsProxy;
 use agama_lib::questions::http_client::HTTPClient;
 use agama_lib::{base_http_client::BaseHTTPClient, connection, error::ServiceError};
 use clap::{Args, Subcommand, ValueEnum};
@@ -60,14 +60,14 @@ pub enum Modes {
     NonInteractive,
 }
 
-async fn set_mode(proxy: Questions1Proxy<'_>, value: Modes) -> Result<(), ServiceError> {
+async fn set_mode(proxy: QuestionsProxy<'_>, value: Modes) -> Result<(), ServiceError> {
     proxy
         .set_interactive(value == Modes::Interactive)
         .await
         .map_err(|e| e.into())
 }
 
-async fn set_answers(proxy: Questions1Proxy<'_>, path: String) -> Result<(), ServiceError> {
+async fn set_answers(proxy: QuestionsProxy<'_>, path: String) -> Result<(), ServiceError> {
     proxy
         .add_answer_file(path.as_str())
         .await
@@ -109,7 +109,7 @@ pub async fn run(
     subcommand: QuestionsCommands,
 ) -> Result<(), ServiceError> {
     let connection = connection().await?;
-    let proxy = Questions1Proxy::new(&connection).await?;
+    let proxy = QuestionsProxy::new(&connection).await?;
 
     match subcommand {
         QuestionsCommands::Mode(value) => set_mode(proxy, value.value).await,

rust/agama-lib/Cargo.toml

@@ -22,11 +22,16 @@ tokio = { version = "1.40.0", features = ["macros", "rt-multi-thread"] }
 tokio-stream = "0.1.16"
 url = "2.5.2"
 utoipa = "4.2.3"
-zbus = { version = "3", default-features = false, features = ["tokio"] }
+zbus = { version = "5", default-features = false, features = ["tokio"] }
 # Needed to define curl error in profile errors
 curl = { version = "0.4.47", features = ["protocol-ftp"] }
 jsonwebtoken = "9.3.0"
-chrono = { version = "0.4.38", default-features = false, features = ["now", "std", "alloc", "clock"] }
+chrono = { version = "0.4.38", default-features = false, features = [
+  "now",
+  "std",
+  "alloc",
+  "clock",
+] }
 home = "0.5.9"
 strum = { version = "0.26.3", features = ["derive"] }
 

rust/agama-lib/src/dbus.rs

@@ -41,7 +41,7 @@ where
             "Failed to find property '{}'",
             name
         )))?
-        .into();
+        .try_into()?;
 
     T::try_from(value).map_err(|e| e.into())
 }
@@ -57,7 +57,7 @@ where
     <T as TryFrom<Value<'a>>>::Error: Into<zbus::zvariant::Error>,
 {
     if let Some(value) = properties.get(name) {
-        let value: Value = value.into();
+        let value: Value = value.try_into()?;
         T::try_from(value).map(|v| Some(v)).map_err(|e| e.into())
     } else {
         Ok(None)
@@ -79,12 +79,14 @@ macro_rules! property_from_dbus {
 /// using the newtype idiom) and offering a better API.
 ///
 /// * `source`: hash map containing non-onwed values ([enum@zbus::zvariant::Value]).
-pub fn to_owned_hash(source: &HashMap<&str, Value<'_>>) -> HashMap<String, OwnedValue> {
+pub fn to_owned_hash<T: ToString>(
+    source: &HashMap<T, Value<'_>>,
+) -> Result<HashMap<String, OwnedValue>, zvariant::Error> {
     let mut owned = HashMap::new();
     for (key, value) in source.iter() {
-        owned.insert(key.to_string(), value.into());
+        owned.insert(key.to_string(), value.try_into()?);
     }
-    owned
+    Ok(owned)
 }
 
 /// Extracts the object ID from the path.

rust/agama-lib/src/lib.rs

@@ -62,6 +62,7 @@ pub mod progress;
 pub mod proxies;
 mod store;
 pub use store::Store;
+use zbus::conn::Builder;
 pub mod questions;
 pub mod scripts;
 pub mod transfer;
@@ -75,7 +76,7 @@ pub async fn connection() -> Result<zbus::Connection, ServiceError> {
 }
 
 pub async fn connection_to(address: &str) -> Result<zbus::Connection, ServiceError> {
-    let connection = zbus::ConnectionBuilder::address(address)?
+    let connection = Builder::address(address)?
         .build()
         .await
         .map_err(|e| ServiceError::DBusConnectionError(address.to_string(), e))?;

rust/agama-lib/src/localization/proxies.rs

@@ -18,47 +18,58 @@
 // To contact SUSE LLC about this file by physical or electronic mail, you may
 // find current contact information at www.suse.com.
 
-use zbus::dbus_proxy;
-
-#[dbus_proxy(
-    interface = "org.opensuse.Agama1.Locale",
+//! # D-Bus interface proxy for: `org.opensuse.Agama1.Locale`
+//!
+//! This code was generated by `zbus-xmlgen` `5.0.0` from D-Bus introspection data.
+//! Source: `org.opensuse.Agama1.Locale.bus.xml`.
+//!
+//! You may prefer to adapt it, instead of using it verbatim.
+//!
+//! More information can be found in the [Writing a client proxy] section of the zbus
+//! documentation.
+//!
+//! This type implements the [D-Bus standard interfaces], (`org.freedesktop.DBus.*`) for which the
+//! following zbus API can be used:
+//!
+//! * [`zbus::fdo::PeerProxy`]
+//! * [`zbus::fdo::PropertiesProxy`]
+//! * [`zbus::fdo::IntrospectableProxy`]
+//!
+//! Consequently `zbus-xmlgen` did not generate code for the above interfaces.
+//!
+//! [Writing a client proxy]: https://dbus2.github.io/zbus/client.html
+//! [D-Bus standard interfaces]: https://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces,
+use zbus::proxy;
+#[proxy(
     default_service = "org.opensuse.Agama1",
-    default_path = "/org/opensuse/Agama1/Locale"
+    interface = "org.opensuse.Agama1.Locale",
+    assume_defaults = true
 )]
-trait Locale {
+pub trait Locale {
     /// Commit method
     fn commit(&self) -> zbus::Result<()>;
 
-    /// ListKeymaps method
-    fn list_keymaps(&self) -> zbus::Result<Vec<(String, String)>>;
-
-    /// ListLocales method
-    fn list_locales(&self) -> zbus::Result<Vec<(String, String, String)>>;
-
-    /// ListTimezones method
-    fn list_timezones(&self) -> zbus::Result<Vec<(String, Vec<String>)>>;
-
     /// Keymap property
-    #[dbus_proxy(property)]
+    #[zbus(property)]
     fn keymap(&self) -> zbus::Result<String>;
-    #[dbus_proxy(property)]
+    #[zbus(property)]
     fn set_keymap(&self, value: &str) -> zbus::Result<()>;
 
     /// Locales property
-    #[dbus_proxy(property)]
+    #[zbus(property)]
     fn locales(&self) -> zbus::Result<Vec<String>>;
-    #[dbus_proxy(property)]
+    #[zbus(property)]
     fn set_locales(&self, value: &[&str]) -> zbus::Result<()>;
 
     /// Timezone property
-    #[dbus_proxy(property)]
+    #[zbus(property)]
     fn timezone(&self) -> zbus::Result<String>;
-    #[dbus_proxy(property)]
+    #[zbus(property)]
     fn set_timezone(&self, value: &str) -> zbus::Result<()>;
 
     /// UILocale property
-    #[dbus_proxy(property, name = "UILocale")]
+    #[zbus(property, name = "UILocale")]
     fn uilocale(&self) -> zbus::Result<String>;
-    #[dbus_proxy(property, name = "UILocale")]
+    #[zbus(property, name = "UILocale")]
     fn set_uilocale(&self, value: &str) -> zbus::Result<()>;
 }

rust/agama-lib/src/network/client.rs

@@ -69,10 +69,10 @@ impl NetworkClient {
 
         if response.is_ok() {
             let path = format!("/network/connections/{id}");
-            self.client.put_void(&path.as_str(), &connection).await?
+            self.client.put_void(path.as_str(), &connection).await?
         } else {
             self.client
-                .post_void(format!("/network/connections").as_str(), &connection)
+                .post_void("/network/connections".to_string().as_str(), &connection)
                 .await?
         }
 
@@ -84,7 +84,7 @@ impl NetworkClient {
         // trying to be tricky here. If something breaks then we need a put method on
         // BaseHTTPClient which doesn't require a serialiable object for the body
         self.client
-            .post_void(&format!("/network/system/apply").as_str(), &())
+            .post_void("/network/system/apply".to_string().as_str(), &())
             .await?;
 
         Ok(())