fix(core): handle EPIPE error in hook runner when writing to stdin (#14231)

packages/core/src/hooks/hookRunner.test.ts

@@ -64,6 +64,7 @@ describe('HookRunner', () => {
       stdin: {
         write: vi.fn(),
         end: vi.fn(),
+        on: vi.fn(),
       } as unknown as Writable,
       stdout: {
         on: mockStdoutOn,

packages/core/src/hooks/hookRunner.ts

@@ -232,6 +232,12 @@ export class HookRunner {
 
       // Send input to stdin
       if (child.stdin) {
+        child.stdin.on('error', (err: NodeJS.ErrnoException) => {
+          // Ignore EPIPE errors which happen when the child process closes stdin early
+          if (err.code !== 'EPIPE') {
+            debugLogger.warn(`Hook stdin error: ${err}`);
+          }
+        });
         child.stdin.write(JSON.stringify(input));
         child.stdin.end();
       }

packages/core/src/hooks/hookSystem.test.ts

@@ -96,6 +96,7 @@ describe('HookSystem Integration', () => {
       stdin: {
         write: vi.fn(),
         end: vi.fn(),
+        on: vi.fn(),
       } as unknown as Writable,
       stdout: {
         on: mockStdoutOn,