fix(core): Resolve AbortSignal MaxListenersExceededWarning (#5950) (#16735)

packages/core/src/agents/local-executor.test.ts

@@ -1369,9 +1369,13 @@ describe('LocalAgentExecutor', () => {
           (async function* () {
             await new Promise<void>((resolve) => {
               // This promise resolves when aborted, ending the generator.
-              signal?.addEventListener('abort', () => {
+              signal?.addEventListener(
+                'abort',
+                () => {
                   resolve();
-              });
+                },
+                { once: true },
+              );
             });
           })(),
       );
@@ -1681,7 +1685,9 @@ describe('LocalAgentExecutor', () => {
           (async function* () {
             // This promise never resolves, it waits for abort.
             await new Promise<void>((resolve) => {
-              signal?.addEventListener('abort', () => resolve());
+              signal?.addEventListener('abort', () => resolve(), {
+                once: true,
+              });
             });
           })(),
       );
@@ -1734,7 +1740,9 @@ describe('LocalAgentExecutor', () => {
           // eslint-disable-next-line require-yield
           (async function* () {
             await new Promise<void>((resolve) =>
-              signal?.addEventListener('abort', () => resolve()),
+              signal?.addEventListener('abort', () => resolve(), {
+                once: true,
+              }),
             );
           })(),
       );
@@ -1745,7 +1753,9 @@ describe('LocalAgentExecutor', () => {
           // eslint-disable-next-line require-yield
           (async function* () {
             await new Promise<void>((resolve) =>
-              signal?.addEventListener('abort', () => resolve()),
+              signal?.addEventListener('abort', () => resolve(), {
+                once: true,
+              }),
             );
           })(),
       );

packages/core/src/services/sessionSummaryService.test.ts

@@ -346,12 +346,16 @@ describe('SessionSummaryService', () => {
               10000,
             );
 
-            abortSignal?.addEventListener('abort', () => {
+            abortSignal?.addEventListener(
+              'abort',
+              () => {
                 clearTimeout(timeoutId);
                 const abortError = new Error('This operation was aborted');
                 abortError.name = 'AbortError';
                 reject(abortError);
-            });
+              },
+              { once: true },
+            );
           }),
       );
 

packages/core/src/tools/mcp-client.test.ts

@@ -1043,10 +1043,13 @@ describe('mcp-client', () => {
               if (options?.signal?.aborted) {
                 return reject(new Error('Operation aborted'));
               }
-              options?.signal?.addEventListener('abort', () => {
+              options?.signal?.addEventListener(
+                'abort',
+                () => {
                   reject(new Error('Operation aborted'));
-              });
+                },
-              // Intentionally do not resolve immediately to simulate lag
+                { once: true },
+              );
             }),
         ),
         listPrompts: vi.fn().mockResolvedValue({ prompts: [] }),

packages/core/src/tools/tools.ts

@@ -242,7 +242,7 @@ export abstract class BaseToolInvocation<
         }
       };
 
-      abortSignal.addEventListener('abort', abortHandler);
+      abortSignal.addEventListener('abort', abortHandler, { once: true });
 
       timeoutId = setTimeout(() => {
         cleanup();

packages/core/src/utils/llm-edit-fixer.test.ts

@@ -350,9 +350,13 @@ describe('FixLLMEditWithInstruction', () => {
           if (abortSignal?.aborted) {
             return reject(new DOMException('Aborted', 'AbortError'));
           }
-          abortSignal?.addEventListener('abort', () => {
+          abortSignal?.addEventListener(
+            'abort',
+            () => {
               reject(new DOMException('Aborted', 'AbortError'));
-          });
+            },
+            { once: true },
+          );
         }),
     );