From 7c169fc9b50a53d0b78f4ad1d14c1bb747ae5ca4 Mon Sep 17 00:00:00 2001
From: Cole Miller <cole@zed.dev>
Date: Thu, 31 Jul 2025 19:45:02 -0400
Subject: [PATCH] debugger: Send initialized event from fake server at a more
 realistic time (#35446)

The spec says:

> :arrow_left: Initialized Event
> This event indicates that the debug adapter is ready to accept
configuration requests (e.g. setBreakpoints, setExceptionBreakpoints).
>
> A debug adapter is expected to send this event when it is ready to
accept configuration requests (but not before the initialize request has
finished).

Previously in tests, `intercept_debug_sessions` was just spawning off a
background task to send the event after setting up the client, so the
event wasn't actually synchronized with the flow of messages in the way
the spec says it should be. This PR makes it so that the `FakeTransport`
injects the event right after a successful response to the initialize
request, and doesn't send it otherwise.

Release Notes:

- N/A
---
 crates/dap/src/client.rs            |  2 +-
 crates/dap/src/transport.rs         | 20 ++++++++++++++++++++
 crates/project/src/debugger/test.rs | 10 +---------
 3 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/crates/dap/src/client.rs b/crates/dap/src/client.rs
index 86a15b2d8a9fa3ce00cdaa2536fb3decce948aec..7b791450ecba3b09b6571ac84fbebdf92fff57b8 100644
--- a/crates/dap/src/client.rs
+++ b/crates/dap/src/client.rs
@@ -295,7 +295,7 @@ mod tests {
                     request: dap_types::StartDebuggingRequestArgumentsRequest::Launch,
                 },
             },
-            Box::new(|_| panic!("Did not expect to hit this code path")),
+            Box::new(|_| {}),
             &mut cx.to_async(),
         )
         .await
diff --git a/crates/dap/src/transport.rs b/crates/dap/src/transport.rs
index 6dadf1cf35d0fc01f91b55a471e2be1e0c7b1be9..f9fbbfc84295bfba946ad96b5eb701d13c6aa52c 100644
--- a/crates/dap/src/transport.rs
+++ b/crates/dap/src/transport.rs
@@ -883,6 +883,7 @@ impl FakeTransport {
                                         break Err(anyhow!("exit in response to request"));
                                     }
                                 };
+                                let success = response.success;
                                 let message =
                                     serde_json::to_string(&Message::Response(response)).unwrap();
 
@@ -893,6 +894,25 @@ impl FakeTransport {
                                     )
                                     .await
                                     .unwrap();
+
+                                if request.command == dap_types::requests::Initialize::COMMAND
+                                    && success
+                                {
+                                    let message = serde_json::to_string(&Message::Event(Box::new(
+                                        dap_types::messages::Events::Initialized(Some(
+                                            Default::default(),
+                                        )),
+                                    )))
+                                    .unwrap();
+                                    writer
+                                        .write_all(
+                                            TransportDelegate::build_rpc_message(message)
+                                                .as_bytes(),
+                                        )
+                                        .await
+                                        .unwrap();
+                                }
+
                                 writer.flush().await.unwrap();
                             }
                         }
diff --git a/crates/project/src/debugger/test.rs b/crates/project/src/debugger/test.rs
index 3b9425e3690fb872b7953634cbdb995a40a5b021..53b88323e6326fe7d6d74f79a5e92845514c6b61 100644
--- a/crates/project/src/debugger/test.rs
+++ b/crates/project/src/debugger/test.rs
@@ -1,7 +1,7 @@
 use std::{path::Path, sync::Arc};
 
 use dap::client::DebugAdapterClient;
-use gpui::{App, AppContext, Subscription};
+use gpui::{App, Subscription};
 
 use super::session::{Session, SessionStateEvent};
 
@@ -19,14 +19,6 @@ pub fn intercept_debug_sessions<T: Fn(&Arc<DebugAdapterClient>) + 'static>(
                     let client = session.adapter_client().unwrap();
                     register_default_handlers(session, &client, cx);
                     configure(&client);
-                    cx.background_spawn(async move {
-                        client
-                            .fake_event(dap::messages::Events::Initialized(
-                                Some(Default::default()),
-                            ))
-                            .await
-                    })
-                    .detach();
                 }
             })
             .detach();