From ce5359d0c504d20cbe60e06183b85e75d1815663 Mon Sep 17 00:00:00 2001
From: FUJITA Tomonori <fujita.tomonori@gmail.com>
Date: Tue, 19 May 2026 03:50:10 +0900
Subject: [PATCH] daemon: make SessionDownReason::FsmError a unit variant
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The State payload was never read — all match arms used FsmError(_).
FsmError occurs mostly before Established (OPEN exchange errors) so
BMP PeerDown is not sent anyway; in the rare post-Established case
the state value adds no actionable information.

Remove the payload and the now-unnecessary #[allow(dead_code)] on
SessionDownReason.

Assisted-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: FUJITA Tomonori <tomonori.fujita@ntt.com>
---
 daemon/src/event.rs |  4 +---
 daemon/src/fsm.rs   | 17 ++++++++---------
 2 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/daemon/src/event.rs b/daemon/src/event.rs
index 6c0c071..3022725 100644
--- a/daemon/src/event.rs
+++ b/daemon/src/event.rs
@@ -4481,9 +4481,7 @@ impl PeerSession {
                         crate::fsm::SessionDownReason::RemoteNotification(msg) => {
                             bmp::PeerDownReason::RemoteNotification(msg)
                         }
-                        crate::fsm::SessionDownReason::FsmError(_) => {
-                            bmp::PeerDownReason::LocalFsm(0)
-                        }
+                        crate::fsm::SessionDownReason::FsmError => bmp::PeerDownReason::LocalFsm(0),
                         crate::fsm::SessionDownReason::AdminShutdown => {
                             bmp::PeerDownReason::LocalFsm(0)
                         }
diff --git a/daemon/src/fsm.rs b/daemon/src/fsm.rs
index 95a6154..bacdfb0 100644
--- a/daemon/src/fsm.rs
+++ b/daemon/src/fsm.rs
@@ -114,11 +114,10 @@ pub(crate) enum Output {
 
 /// Reason the session is going down.
 #[derive(Clone)]
-#[allow(dead_code)]
 pub(crate) enum SessionDownReason {
     HoldTimerExpired,
     RemoteNotification(bgp::Message),
-    FsmError(State),
+    FsmError,
     AdminShutdown,
     IoError,
 }
@@ -240,7 +239,7 @@ impl Connection {
                         state: u8::from(self.state),
                     },
                 )),
-                Output::SessionDown(SessionDownReason::FsmError(self.state)),
+                Output::SessionDown(SessionDownReason::FsmError),
             ];
         }
 
@@ -317,7 +316,7 @@ impl Connection {
                         state: u8::from(self.state),
                     },
                 )),
-                Output::SessionDown(SessionDownReason::FsmError(self.state)),
+                Output::SessionDown(SessionDownReason::FsmError),
             ],
         }
     }
@@ -330,7 +329,7 @@ impl Connection {
                         state: u8::from(self.state),
                     },
                 )),
-                Output::SessionDown(SessionDownReason::FsmError(self.state)),
+                Output::SessionDown(SessionDownReason::FsmError),
             ];
         }
         vec![Output::SetHoldTimer(self.negotiated_holdtime)]
@@ -350,7 +349,7 @@ impl Connection {
                         state: u8::from(self.state),
                     },
                 )),
-                Output::SessionDown(SessionDownReason::FsmError(self.state)),
+                Output::SessionDown(SessionDownReason::FsmError),
             ];
         }
         vec![Output::RouteRefresh(family)]
@@ -750,7 +749,7 @@ mod tests {
         )));
         assert!(has_output(&out, |o| matches!(
             o,
-            Output::SessionDown(SessionDownReason::FsmError(_))
+            Output::SessionDown(SessionDownReason::FsmError)
         )));
     }
 
@@ -952,7 +951,7 @@ mod tests {
         )));
         assert!(has_output(&out, |o| matches!(
             o,
-            Output::SessionDown(SessionDownReason::FsmError(_))
+            Output::SessionDown(SessionDownReason::FsmError)
         )));
     }
 
@@ -992,7 +991,7 @@ mod tests {
         )));
         assert!(has_output(&out, |o| matches!(
             o,
-            Output::SessionDown(SessionDownReason::FsmError(_))
+            Output::SessionDown(SessionDownReason::FsmError)
         )));
     }