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 86a15b2d8a..7b791450ec 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 6dadf1cf35..f9fbbfc842 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 3b9425e369..53b88323e6 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();