Downgrade ExecutionTerminated to debug

Detect closed peer so that subsequent sends don't keep trying and failing

src/Watchdog.zig

@@ -132,7 +132,7 @@ fn run(self: *Watchdog) void {
 
             if (entry.fired == false) {
                 entry.fired = true;
-                log.err(.app, "watchdog stall", .{ .stalled_ms = stalled_ms });
+                log.warn(.app, "watchdog stall", .{ .stalled_ms = stalled_ms });
                 entry.env.requestTerminate();
             }
         }

src/browser/Frame.zig

@@ -1255,7 +1255,9 @@ pub fn documentIsLoaded(self: *Frame) void {
     self.document._ready_state = .interactive;
     self._documentIsLoaded() catch |err| switch (err) {
         error.JsException => {}, // already logged
-        else => log.err(.frame, "document is loaded2", .{ .err = err, .type = self._type, .url = self.url }),
+        // logged by whatever requested the terminate (watchdog, runaway loop)
+        error.ExecutionTerminated => log.debug(.frame, "document is loaded", .{ .err = err, .type = self._type, .url = self.url }),
+        else => log.err(.frame, "document is loaded", .{ .err = err, .type = self._type, .url = self.url }),
     };
 }
 
@@ -1359,6 +1361,8 @@ pub fn documentIsComplete(self: *Frame) void {
     self._load_state = .complete;
     self._documentIsComplete() catch |err| switch (err) {
         error.JsException => {}, // already logged
+        // logged by whatever requested the terminate (watchdog, runaway loop)
+        error.ExecutionTerminated => log.debug(.frame, "document is complete", .{ .err = err, .type = self._type, .url = self.url }),
         else => log.err(.frame, "document is complete", .{ .err = err, .type = self._type, .url = self.url }),
     };
 

src/server/Link.zig

@@ -60,6 +60,7 @@ send_arena: ArenaAllocator,
 send_depth: u32,
 send_timeout_ms: i32,
 max_inbox_backlog: usize,
+peer_closed: bool,
 
 pub fn init(
     self: *Link,
@@ -91,6 +92,7 @@ pub fn init(
         .send_depth = 0,
         .send_timeout_ms = SEND_TIMEOUT_MS,
         .max_inbox_backlog = @as(usize, config.cdpMaxMessageSize()) * INBOX_BACKLOG_MESSAGES,
+        .peer_closed = false,
     };
 }
 
@@ -132,6 +134,10 @@ pub fn releaseSendArena(self: *Link) void {
 }
 
 pub fn send(self: *Link, data: []const u8) !void {
+    if (self.peer_closed) {
+        return;
+    }
+
     var pos: usize = 0;
     const socket = self.socket;
 
@@ -157,6 +163,11 @@ pub fn send(self: *Link, data: []const u8) !void {
             },
             // a signal landed mid-write; nothing was written
             error.Interrupted => continue,
+            error.BrokenPipe, error.ConnectionResetByPeer => {
+                lp.log.debug(.app, "link peer closed", .{ .err = err });
+                self.peer_closed = true;
+                return;
+            },
             else => return err,
         };