From f126b34effd92ba7412f35e9a60b08cfd5425472 Mon Sep 17 00:00:00 2001
From: Daniel Sauer <daniel.a.d.sauer@gmail.com>
Date: Sat, 17 Jan 2026 23:46:52 +0100
Subject: [PATCH] fix(acp): Fix memory leak in session map and event streams

Add cleanup mechanism for ACP session map and event streams to prevent
unbounded growth. Implements proper session lifecycle management.
---
 packages/opencode/src/acp/agent.ts   | 34 ++++++++++++++++++++++++++++
 packages/opencode/src/acp/session.ts |  8 +++++++
 2 files changed, 42 insertions(+)

diff --git a/packages/opencode/src/acp/agent.ts b/packages/opencode/src/acp/agent.ts
index 9512406b3d47..2c5464d11546 100644
--- a/packages/opencode/src/acp/agent.ts
+++ b/packages/opencode/src/acp/agent.ts
@@ -259,6 +259,12 @@ export namespace ACP {
           return
         }
 
+        case "session.deleted": {
+          const sessionId = event.properties.info.id
+          this.closeSession(sessionId)
+          return
+        }
+
         case "message.part.updated": {
           log.info("message part updated", { event: event.properties })
           const props = event.properties
@@ -1432,6 +1438,34 @@ export namespace ACP {
         { throwOnError: true },
       )
     }
+
+    /**
+     * Dispose of all session resources including event streams and session map entries.
+     * This should be called when the agent is being destroyed to prevent memory leaks.
+     */
+    async dispose() {
+      log.info("disposing agent", { sessionCount: this.sessionManager["sessions"].size })
+
+      // Abort global event stream
+      this.eventAbort.abort()
+
+      // Clear all sessions from the manager
+      this.sessionManager.clear()
+    }
+
+    /**
+     * Close a specific session and clean up its resources.
+     * This should be called when a session is explicitly closed/ended.
+     */
+    closeSession(sessionId: string) {
+      log.info("closing session", { sessionId })
+
+      // Remove from session manager
+      this.sessionManager.delete(sessionId)
+
+      // Clean up permission queue if present
+      this.permissionQueues.delete(sessionId)
+    }
   }
 
   function toToolKind(toolName: string): ToolKind {
diff --git a/packages/opencode/src/acp/session.ts b/packages/opencode/src/acp/session.ts
index 18aa42313017..5159989223cf 100644
--- a/packages/opencode/src/acp/session.ts
+++ b/packages/opencode/src/acp/session.ts
@@ -13,6 +13,14 @@ export class ACPSessionManager {
     this.sdk = sdk
   }
 
+  delete(sessionId: string): boolean {
+    return this.sessions.delete(sessionId)
+  }
+
+  clear(): void {
+    this.sessions.clear()
+  }
+
   tryGet(sessionId: string): ACPSessionState | undefined {
     return this.sessions.get(sessionId)
   }