feat: rustc and clippy linting

server/crates/arbiter-server/src/db/mod.rs

@@ -23,14 +23,14 @@ const MIGRATIONS: EmbeddedMigrations = embed_migrations!("migrations");
 
 #[derive(Error, Debug)]
 pub enum DatabaseSetupError {
-    #[error("Failed to determine home directory")]
-    HomeDir(std::io::Error),
+    #[error(transparent)]
+    ConcurrencySetup(diesel::result::Error),
 
     #[error(transparent)]
     Connection(diesel::ConnectionError),
 
-    #[error(transparent)]
-    ConcurrencySetup(diesel::result::Error),
+    #[error("Failed to determine home directory")]
+    HomeDir(std::io::Error),
 
     #[error(transparent)]
     Migration(Box<dyn std::error::Error + Send + Sync>),
@@ -41,10 +41,11 @@ pub enum DatabaseSetupError {
 
 #[derive(Error, Debug)]
 pub enum DatabaseError {
-    #[error("Database connection error")]
-    Pool(#[from] PoolError),
     #[error("Database query error")]
     Connection(#[from] diesel::result::Error),
+
+    #[error("Database connection error")]
+    Pool(#[from] PoolError),
 }
 
 #[tracing::instrument(level = "info")]
@@ -93,13 +94,16 @@ fn initialize_database(url: &str) -> Result<(), DatabaseSetupError> {
 }
 
 #[tracing::instrument(level = "info")]
+/// Creates a connection pool for the `SQLite` database.
+///
+/// # Panics
+/// Panics if the database path is not valid UTF-8.
 pub async fn create_pool(url: Option<&str>) -> Result<DatabasePool, DatabaseSetupError> {
     let database_url = url.map(String::from).unwrap_or(
-        #[allow(clippy::expect_used)]
         database_path()?
             .to_str()
             .expect("database path is not valid UTF-8")
-            .to_string(),
+            .to_owned(),
     );
 
     initialize_database(&database_url)?;
@@ -134,19 +138,19 @@ pub async fn create_pool(url: Option<&str>) -> Result<DatabasePool, DatabaseSetu
 }
 
 #[mutants::skip]
+#[expect(clippy::missing_panics_doc, reason = "Tests oriented function")]
+/// Creates a test database pool with a temporary `SQLite` database file.
 pub async fn create_test_pool() -> DatabasePool {
     use rand::distr::{Alphanumeric, SampleString as _};
 
     let tempfile_name = Alphanumeric.sample_string(&mut rand::rng(), 16);
 
     let file = std::env::temp_dir().join(tempfile_name);
-    #[allow(clippy::expect_used)]
     let url = file
         .to_str()
         .expect("temp file path is not valid UTF-8")
-        .to_string();
+        .to_owned();
 
-    #[allow(clippy::expect_used)]
     create_pool(Some(&url))
         .await
         .expect("Failed to create test database pool")