feat: add SessionClosed error

zenoh/src/api/session.rs

@@ -185,7 +185,7 @@ impl SessionState {
         self.primitives
             .as_ref()
             .cloned()
-            .ok_or_else(|| zerror!("session closed").into())
+            .ok_or_else(|| SessionClosedError.into())
     }
 
     #[inline]
@@ -516,6 +516,21 @@ impl Drop for WeakSession {
     }
 }
 
+/// Error indicating the operation cannot proceed because the session is closed.
+///
+/// It may be returned by operations like [`Session::get`] or [`Publisher::put`] when
+/// [`Session::close`] has been called before.
+#[derive(Debug)]
+pub struct SessionClosedError;
+
+impl fmt::Display for SessionClosedError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "session closed")
+    }
+}
+
+impl std::error::Error for SessionClosedError {}
+
 static SESSION_ID_COUNTER: AtomicU16 = AtomicU16::new(0);
 impl Session {
     pub(crate) fn init(

zenoh/src/lib.rs

@@ -193,7 +193,7 @@ pub mod session {
         builders::publisher::{SessionDeleteBuilder, SessionPutBuilder},
         info::{PeersZenohIdBuilder, RoutersZenohIdBuilder, SessionInfo, ZenohIdBuilder},
         query::SessionGetBuilder,
-        session::{open, OpenBuilder, Session, Undeclarable},
+        session::{open, OpenBuilder, Session, SessionClosedError, Undeclarable},
     };
 }