harden(auth): distinguish session-store failure (500) from absent session (401); exhaustive marker + verify_dummy tests

crates/auth/src/lib.rs

@@ -73,6 +73,10 @@ pub enum AuthError {
     Unauthenticated,
     #[error("insufficient permissions")]
     Forbidden,
+    /// The session store itself failed (e.g. the database is unreachable) — distinct
+    /// from "no session", so an outage surfaces as 500 rather than a misleading 401.
+    #[error("session store unavailable")]
+    Internal,
 }
 
 impl IntoResponse for AuthError {
@@ -80,6 +84,7 @@ impl IntoResponse for AuthError {
         match self {
             AuthError::Unauthenticated => StatusCode::UNAUTHORIZED,
             AuthError::Forbidden => StatusCode::FORBIDDEN,
+            AuthError::Internal => StatusCode::INTERNAL_SERVER_ERROR,
         }
         .into_response()
     }
@@ -101,29 +106,30 @@ where
     type Rejection = AuthError;
 
     async fn from_request_parts(parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
+        // A failed extraction here means the SessionManagerLayer is missing from the
+        // stack — a wiring bug, not an auth failure: surface it as 500.
         let session = Session::from_request_parts(parts, state)
             .await
-            .map_err(|_| AuthError::Unauthenticated)?;
+            .map_err(|_| AuthError::Internal)?;
 
+        // For each key: a store error (DB down) is `Internal` (500); an absent key is
+        // `Unauthenticated` (401) — these must not be conflated.
         let id: uuid::Uuid = session
             .get(SESSION_USER_ID)
             .await
-            .ok()
-            .flatten()
+            .map_err(|_| AuthError::Internal)?
             .ok_or(AuthError::Unauthenticated)?;
 
         let email: String = session
             .get(SESSION_EMAIL)
             .await
-            .ok()
-            .flatten()
+            .map_err(|_| AuthError::Internal)?
             .ok_or(AuthError::Unauthenticated)?;
 
         let role_str: String = session
             .get(SESSION_ROLE)
             .await
-            .ok()
-            .flatten()
+            .map_err(|_| AuthError::Internal)?
             .ok_or(AuthError::Unauthenticated)?;
 
         let role = Role::from_db(&role_str).ok_or(AuthError::Unauthenticated)?;
@@ -221,9 +227,17 @@ mod tests {
         assert!(!verify_password("anything", "not-a-phc-string"));
     }
 
+    #[test]
+    fn verify_dummy_does_not_panic() {
+        verify_dummy("any input");
+        verify_dummy("called again"); // exercises the already-initialized OnceLock path
+    }
+
     #[test]
     fn capability_markers_map_to_domain_capabilities() {
         assert_eq!(ManageUsers::CAP, domain::Capability::ManageUsers);
+        assert_eq!(EditCatalogue::CAP, domain::Capability::EditCatalogue);
         assert_eq!(PublishObjects::CAP, domain::Capability::PublishObjects);
+        assert_eq!(ViewInternal::CAP, domain::Capability::ViewInternal);
     }
 }