[Lldb-commits] [lldb] [vscode-lldb] Fix race condition when changing lldb-dap arguments (PR #151828)

[via lldb-commits]

https://github.com/royitaqi updated https://github.com/llvm/llvm-project/pull/151828

>From b58e5d4fe42a499dc7b9d903f56d62fc993f67a2 Mon Sep 17 00:00:00 2001
From: Roy Shi <royshi at meta.com>
Date: Sat, 2 Aug 2025 09:30:25 -0700
Subject: [PATCH 1/2] [vscode-lldb] Fix race condition when changing lldb-dap
 arguments

---
 lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts b/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts
index 79573ec7342b1..c4e99a3178e8c 100644
--- a/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts
+++ b/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts
@@ -39,8 +39,10 @@ export class LLDBDapServer implements vscode.Disposable {
       const process = child_process.spawn(dapPath, dapArgs, options);
       process.on("error", (error) => {
         reject(error);
-        this.serverProcess = undefined;
-        this.serverInfo = undefined;
+        if (this.serverProcess === process) {
+          this.serverProcess = undefined;
+          this.serverInfo = undefined;
+        }
       });
       process.on("exit", (code, signal) => {
         let errorMessage = "Server process exited early";
@@ -50,8 +52,10 @@ export class LLDBDapServer implements vscode.Disposable {
           errorMessage += ` due to signal ${signal}`;
         }
         reject(new Error(errorMessage));
-        this.serverProcess = undefined;
-        this.serverInfo = undefined;
+        if (this.serverProcess === process) {
+          this.serverProcess = undefined;
+          this.serverInfo = undefined;
+        }
       });
       process.stdout.setEncoding("utf8").on("data", (data) => {
         const connection = /connection:\/\/\[([^\]]+)\]:(\d+)/.exec(

>From 852216b6fba70668b7f7453e64c1e237b3b63d89 Mon Sep 17 00:00:00 2001
From: Roy Shi <royshi at meta.com>
Date: Tue, 5 Aug 2025 11:46:01 -0700
Subject: [PATCH 2/2] Add a util function `cleanUp`

---
 lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts | 23 +++++++++++--------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts b/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts
index c4e99a3178e8c..34908bb7b33aa 100644
--- a/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts
+++ b/lldb/tools/lldb-dap/src-ts/lldb-dap-server.ts
@@ -39,10 +39,7 @@ export class LLDBDapServer implements vscode.Disposable {
       const process = child_process.spawn(dapPath, dapArgs, options);
       process.on("error", (error) => {
         reject(error);
-        if (this.serverProcess === process) {
-          this.serverProcess = undefined;
-          this.serverInfo = undefined;
-        }
+        this.cleanUp(process);
       });
       process.on("exit", (code, signal) => {
         let errorMessage = "Server process exited early";
@@ -52,10 +49,7 @@ export class LLDBDapServer implements vscode.Disposable {
           errorMessage += ` due to signal ${signal}`;
         }
         reject(new Error(errorMessage));
-        if (this.serverProcess === process) {
-          this.serverProcess = undefined;
-          this.serverInfo = undefined;
-        }
+        this.cleanUp(process);
       });
       process.stdout.setEncoding("utf8").on("data", (data) => {
         const connection = /connection:\/\/\[([^\]]+)\]:(\d+)/.exec(
@@ -130,7 +124,16 @@ Restarting the server will interrupt any existing debug sessions and start a new
       return;
     }
     this.serverProcess.kill();
-    this.serverProcess = undefined;
-    this.serverInfo = undefined;
+    this.cleanUp(this.serverProcess);
+  }
+
+  cleanUp(process: child_process.ChildProcessWithoutNullStreams) {
+    // If the following don't equal, then the fields have already been updated
+    // (either a new process has started, or the fields were already cleaned
+    // up), and so the cleanup should be skipped.
+    if (this.serverProcess === process) {
+      this.serverProcess = undefined;
+      this.serverInfo = undefined;
+    }
   }
 }