feat(rust): adapt to zbus 5

[imobachgs]

The main goal

Although zbus 5 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) if you are interested in further improvements.
• Drop some unused code.

Tasks

• Testing, testing and testing.
• Update some outdated D-Bus definitions.
• Improve the network::nm::dbus module.

[coveralls]

Pull Request Test Coverage Report for Build 11700249506

Details

• 185 of 324 (57.1%) changed or added relevant lines in 23 files are covered.
• 13 unchanged lines in 6 files lost coverage.
• Overall coverage increased (+0.007%) to 71.486%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
rust/agama-lib/src/questions/http_client.rs	0	1	0.0%
rust/agama-lib/src/scripts/model.rs	0	1	0.0%
rust/agama-lib/src/storage/model.rs	0	1	0.0%
rust/agama-server/src/storage/web/iscsi.rs	0	1	0.0%
rust/agama-server/src/web/common.rs	0	1	0.0%
rust/agama-lib/src/progress.rs	0	2	0.0%
rust/agama-server/src/storage/web/zfcp/stream.rs	0	2	0.0%
rust/agama-cli/src/questions.rs	0	3	0.0%
rust/agama-lib/src/network/client.rs	0	3	0.0%
rust/agama-lib/src/product/client.rs	0	3	0.0%

Files with Coverage Reduction	New Missed Lines	%
rust/agama-lib/src/storage/client/iscsi.rs	1	0.0%
rust/agama-server/src/network/nm/builder.rs	1	0.0%
rust/agama-server/src/users/web.rs	1	0.0%
rust/agama-lib/src/storage/client/zfcp.rs	2	0.0%
rust/agama-server/src/network/nm/dbus.rs	3	76.16%
rust/agama-server/tests/common/mod.rs	5	74.19%

Totals
Change from base Build 11679986183:	0.007%
Covered Lines:	16890
Relevant Lines:	23627

---

💛 - Coveralls

[teclator]

LGTM

[jcronenberg]

I mostly looked at the NM dbus code, because that's what I know, but it looks like a nice improvement all around 🙂

[jreidinger]

I have feeling that this be written better, but sadly do not have idea how....so lets keep it so far

[jreidinger]

nothing critical

[mvidner]

@imobachgs I know this is just test code, but it bothered me how the meaningful text was lost among the boilerplate, so I made a helper for readability:

diff --git a/rust/agama-server/src/network/nm/dbus.rs b/rust/agama-server/src/network/nm/dbus.rs
index 3e4ab1bf6..99e69ad2e 100644
--- a/rust/agama-server/src/network/nm/dbus.rs
+++ b/rust/agama-server/src/network/nm/dbus.rs
@@ -1195,6 +1195,14 @@ mod test {
     use uuid::Uuid;
     use zbus::zvariant::{self, Array, Dict, OwnedValue, Value};
 
+    // hash item
+    fn hi<'a, T>(key: &str, value: T) -> anyhow::Result<(String, OwnedValue)>
+    where
+        T: Into<Value<'a>> + zbus::zvariant::Type,
+    {
+        Ok((key.to_string(), Value::new(value).try_to_owned()?))
+    }
+
     #[test]
     fn test_connection_from_dbus() -> anyhow::Result<()> {
         let uuid = Uuid::new_v4().to_string();
@@ -1216,31 +1231,13 @@ mod test {
         ])];
 
         let ipv4_section = HashMap::from([
-            ("method".to_string(), Value::new("auto").try_to_owned()?),
-            (
-                "address-data".to_string(),
-                Value::new(address_v4_data).try_to_owned()?,
-            ),
-            (
-                "gateway".to_string(),
-                Value::new("192.168.0.1").try_to_owned()?,
-            ),
-            (
-                "dns-data".to_string(),
-                Value::new(vec!["192.168.0.2"]).try_to_owned()?,
-            ),
-            (
-                "dns-search".to_string(),
-                Value::new(vec!["suse.com", "example.com"]).try_to_owned()?,
-            ),
-            (
-                "ignore-auto-dns".to_string(),
-                Value::new(true).try_to_owned()?,
-            ),
-            (
-                "route-data".to_string(),
-                Value::new(route_v4_data).try_to_owned()?,
-            ),
+            hi("method", "auto")?,
+            hi("address-data", address_v4_data)?,
+            hi("gateway", "192.168.0.1")?,
+            hi("dns-data", vec!["192.168.0.2"])?,
+            hi("dns-search", vec!["suse.com", "example.com"])?,
+            hi("ignore-auto-dns", true)?,
+            hi("route-data", route_v4_data)?,
         ]);
 
         let address_v6_data = vec![HashMap::from([