fix: suppress error from process.kill when killing tasks on failure

lib/resolveTaskFn.js

@@ -54,12 +54,16 @@ const killExecaProcess = async (execaProcess) => {
   try {
     const childPids = await pidTree(execaProcess.pid)
     for (const childPid of childPids) {
-      process.kill(childPid)
+      try {
+        process.kill(childPid)
+      } catch (error) {
+        debugLog(`Failed to kill process with pid "%d": %o`, childPid, error)
+      }
     }
   } catch (error) {
     // Suppress "No matching pid found" error. This probably means
     // the process already died before executing.
-    debugLog(`Failed to find process for pid %d`, execaProcess.pid)
+    debugLog(`Failed to kill process with pid "%d": %o`, execaProcess.pid, error)
   }
 
   // The execa process is killed separately in order to get the `KILLED` status.

test/resolveTaskFn.spec.js

@@ -484,4 +484,51 @@ describe('resolveTaskFn', () => {
       value: realKill,
     })
   })
+
+  it('should ignore error when trying to kill child processes', async () => {
+    expect.assertions(3)
+
+    execa.mockImplementationOnce(() =>
+      createExecaReturnValue(
+        {
+          stdout: 'a-ok',
+          stderr: '',
+          code: 0,
+          cmd: 'mock cmd',
+          failed: false,
+          killed: false,
+          signal: null,
+        },
+        1000
+      )
+    )
+
+    const realKill = process.kill
+    const mockKill = jest.fn(() => {
+      throw new Error('kill ESRCH')
+    })
+    Object.defineProperty(process, 'kill', {
+      value: mockKill,
+    })
+
+    pidTree.mockImplementationOnce(() => ['1234'])
+
+    const taskFn = resolveTaskFn({ command: 'node' })
+
+    const context = getInitialState()
+    const taskPromise = taskFn(context)
+
+    context.events.emit('lint-staged:taskError')
+
+    jest.runAllTimers()
+
+    await expect(taskPromise).rejects.toThrowErrorMatchingInlineSnapshot(`"node [KILLED]"`)
+
+    expect(mockKill).toHaveBeenCalledTimes(1)
+    expect(mockKill).toHaveBeenCalledWith('1234')
+
+    Object.defineProperty(process, 'kill', {
+      value: realKill,
+    })
+  })
 })