From 4d07e0339569461ac1a4c90c02dfcba7e5fad089 Mon Sep 17 00:00:00 2001
From: Mollusk <silvernode@gmail.com>
Date: Fri, 19 Jun 2026 15:57:35 -0400
Subject: [PATCH] core: skip network-stack rebuild when SetNetworkMode is a
 no-op
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The GUI re-sends the saved network mode as part of its startup config-sync.
The SetNetworkMode handler unconditionally tore down + rebuilt the iroh
endpoint whenever idle, so every launch rebuilt the freshly-built stack for
an identical posture — a needless ~1s teardown+rebuild bounce visible in the
logs on both Linux and Windows/Wine (the 'start core loop -> shut down network
stack ~1s later' pattern from the Wine spike). Guard the rebuild on an actual
mode change; a real change still rebuilds exactly as before.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 src/core/mod.rs | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/src/core/mod.rs b/src/core/mod.rs
index e3bc8d9..afd8341 100644
--- a/src/core/mod.rs
+++ b/src/core/mod.rs
@@ -1816,17 +1816,26 @@ async fn run_core_loop(
             }
 
             CoreCommand::SetNetworkMode(mode) => {
-                network_mode = mode;
-                // Rebuild the persistent stack to the new posture immediately if
-                // idle; if a call is active, defer to the next Leave/Join so the
-                // live call isn't disrupted (preserves "applies on next join").
-                if active_session.is_none() {
-                    let lookup = net.memory_lookup.clone();
-                    net.shutdown().await;
-                    let publish = presence_mode.lock().unwrap().publishes_to_discovery();
-                    net = build_net_stack(secret_key.clone(), network_mode, lookup, friends_handler.clone(), publish).await?;
-                } else {
-                    net_rebuild_pending = true;
+                // Skip when the posture is unchanged. The GUI re-sends the saved
+                // network mode as part of its startup config-sync, and that mode
+                // usually already matches the freshly-built stack — rebuilding the
+                // iroh endpoint for an identical posture just churns the network
+                // and adds a needless ~1s teardown+rebuild bounce at every launch
+                // (seen on both Linux and Windows/Wine). A real change still
+                // rebuilds exactly as before.
+                if mode != network_mode {
+                    network_mode = mode;
+                    // Rebuild the persistent stack to the new posture immediately if
+                    // idle; if a call is active, defer to the next Leave/Join so the
+                    // live call isn't disrupted (preserves "applies on next join").
+                    if active_session.is_none() {
+                        let lookup = net.memory_lookup.clone();
+                        net.shutdown().await;
+                        let publish = presence_mode.lock().unwrap().publishes_to_discovery();
+                        net = build_net_stack(secret_key.clone(), network_mode, lookup, friends_handler.clone(), publish).await?;
+                    } else {
+                        net_rebuild_pending = true;
+                    }
                 }
             }