From 568d24d4e3ef55c600431c0ad430bb350c4fe022 Mon Sep 17 00:00:00 2001
From: atbrakhi <atbrakhi@igalia.com>
Date: Sat, 31 May 2025 08:51:03 +0200
Subject: [PATCH] DevTools: Fix empty `debugger > source` panel (#37197)

This patch fixes the source panel in the DevTools that was broken due to
missing breakpoint actor implementation. The client was sending messages
to the breakpoint actor that didn't exist in Servo, resulting in
"unknown actor"
warnings in the logs(See logs in issue description)

To fix this this patch implements the `BreakpointListActor` that handles
`setBreakpoint` and `setActiveEventBreakpoints` messages with empty
replies. This PR does not implement `breakpoint` functionality

<img width="1512" alt="image"
src="https://github.com/user-attachments/assets/ac4985a6-9fd3-4854-a491-b39241e19d13"
/>



Fixes: https://github.com/servo/servo/issues/37196

Signed-off-by: atbrakhi <atbrakhi@igalia.com>
---
 components/devtools/actors/breakpoint.rs | 55 ++++++++++++++++++++++++
 components/devtools/actors/watcher.rs    |  7 ++-
 components/devtools/lib.rs               |  1 +
 3 files changed, 62 insertions(+), 1 deletion(-)
 create mode 100644 components/devtools/actors/breakpoint.rs

diff --git a/components/devtools/actors/breakpoint.rs b/components/devtools/actors/breakpoint.rs
new file mode 100644
index 00000000000..04f2de140b4
--- /dev/null
+++ b/components/devtools/actors/breakpoint.rs
@@ -0,0 +1,55 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use serde::Serialize;
+
+use crate::EmptyReplyMsg;
+use crate::actor::{Actor, ActorMessageStatus};
+use crate::protocol::JsonPacketStream;
+
+#[derive(Serialize)]
+pub struct BreakpointListActorMsg {
+    actor: String,
+}
+
+pub struct BreakpointListActor {
+    name: String,
+}
+
+impl Actor for BreakpointListActor {
+    fn name(&self) -> String {
+        self.name.clone()
+    }
+
+    fn handle_message(
+        &self,
+        _registry: &crate::actor::ActorRegistry,
+        msg_type: &str,
+        _msg: &serde_json::Map<String, serde_json::Value>,
+        stream: &mut std::net::TcpStream,
+        _stream_id: crate::StreamId,
+    ) -> Result<crate::actor::ActorMessageStatus, ()> {
+        Ok(match msg_type {
+            "setBreakpoint" => {
+                let msg = EmptyReplyMsg { from: self.name() };
+                let _ = stream.write_json_packet(&msg);
+
+                ActorMessageStatus::Processed
+            },
+            "setActiveEventBreakpoints" => {
+                let msg = EmptyReplyMsg { from: self.name() };
+                let _ = stream.write_json_packet(&msg);
+
+                ActorMessageStatus::Processed
+            },
+            _ => ActorMessageStatus::Ignored,
+        })
+    }
+}
+
+impl BreakpointListActor {
+    pub fn new(name: String) -> Self {
+        Self { name }
+    }
+}
diff --git a/components/devtools/actors/watcher.rs b/components/devtools/actors/watcher.rs
index 061ffc92336..7720daf070d 100644
--- a/components/devtools/actors/watcher.rs
+++ b/components/devtools/actors/watcher.rs
@@ -19,6 +19,7 @@ use serde::Serialize;
 use serde_json::{Map, Value};
 
 use self::network_parent::{NetworkParentActor, NetworkParentActorMsg};
+use super::breakpoint::BreakpointListActor;
 use super::thread::ThreadActor;
 use super::worker::WorkerMsg;
 use crate::actor::{Actor, ActorMessageStatus, ActorRegistry};
@@ -362,10 +363,14 @@ impl Actor for WatcherActor {
                 ActorMessageStatus::Processed
             },
             "getBreakpointListActor" => {
+                let breakpoint_list_name = registry.new_name("breakpoint-list");
+                let breakpoint_list = BreakpointListActor::new(breakpoint_list_name.clone());
+                registry.register_later(Box::new(breakpoint_list));
+
                 let _ = stream.write_json_packet(&GetBreakpointListActorReply {
                     from: self.name(),
                     breakpoint_list: GetBreakpointListActorReplyInner {
-                        actor: registry.new_name("breakpoint-list"),
+                        actor: breakpoint_list_name,
                     },
                 });
                 ActorMessageStatus::Processed
diff --git a/components/devtools/lib.rs b/components/devtools/lib.rs
index d097cb25e9d..74a45eaf866 100644
--- a/components/devtools/lib.rs
+++ b/components/devtools/lib.rs
@@ -53,6 +53,7 @@ use crate::protocol::JsonPacketStream;
 mod actor;
 /// <https://searchfox.org/mozilla-central/source/devtools/server/actors>
 mod actors {
+    pub mod breakpoint;
     pub mod browsing_context;
     pub mod console;
     pub mod device;