From 6bcab282ffc16f4340c015f195a919bc31891704 Mon Sep 17 00:00:00 2001
From: Bert Blommers <info@bertblommers.nl>
Date: Sun, 10 Dec 2023 08:22:26 -0100
Subject: [PATCH] Batch: Only join running Threads (#7105)

---
 moto/batch/models.py                |  3 ++-
 tests/test_batch/test_batch_jobs.py | 38 +++++++++++++++++++++++++++--
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/moto/batch/models.py b/moto/batch/models.py
index 0f6879ae9..105ff3ae9 100644
--- a/moto/batch/models.py
+++ b/moto/batch/models.py
@@ -1055,7 +1055,8 @@ class BatchBackend(BaseBackend):
             if job.status not in (JobStatus.FAILED, JobStatus.SUCCEEDED):
                 job.stop = True
                 # Try to join
-                job.join(0.2)
+                if job.is_alive():
+                    job.join(0.2)
 
         super().reset()
 
diff --git a/tests/test_batch/test_batch_jobs.py b/tests/test_batch/test_batch_jobs.py
index 428f94961..1174e59a3 100644
--- a/tests/test_batch/test_batch_jobs.py
+++ b/tests/test_batch/test_batch_jobs.py
@@ -1,15 +1,16 @@
 import datetime
 import time
+from unittest import SkipTest
 from uuid import uuid4
 
 import botocore.exceptions
 import pytest
 
-from moto import mock_batch, mock_ec2, mock_ecs, mock_iam, mock_logs
+from moto import mock_batch, mock_ec2, mock_ecs, mock_iam, mock_logs, settings
 from tests import DEFAULT_ACCOUNT_ID
 
 from ..markers import requires_docker
-from . import _get_clients, _setup
+from . import DEFAULT_REGION, _get_clients, _setup
 
 
 @mock_logs
@@ -137,6 +138,39 @@ def test_submit_job_array_size():
     assert len(child_job_1["attempts"]) == 1
 
 
+@mock_ec2
+@mock_ecs
+@mock_iam
+@mock_batch
+@pytest.mark.network
+@requires_docker
+def test_submit_job_array_size__reset_while_job_is_running():
+    if settings.TEST_SERVER_MODE:
+        raise SkipTest("No point testing this in ServerMode")
+
+    # Setup
+    job_definition_name = f"echo_{str(uuid4())[0:6]}"
+    ec2_client, iam_client, _, _, batch_client = _get_clients()
+    commands = ["echo", "hello"]
+    _, _, _, iam_arn = _setup(ec2_client, iam_client)
+    _, queue_arn = prepare_job(batch_client, commands, iam_arn, job_definition_name)
+
+    # Execute
+    batch_client.submit_job(
+        jobName="test1",
+        jobQueue=queue_arn,
+        jobDefinition=job_definition_name,
+        arrayProperties={"size": 2},
+    )
+
+    from moto.batch import batch_backends
+
+    # This method will try to join on (wait for) any created JobThreads
+    # The parent of the ArrayJobs is created, but never started
+    # So we need to make sure that we don't join on any Threads that are never started in the first place
+    batch_backends[DEFAULT_ACCOUNT_ID][DEFAULT_REGION].reset()
+
+
 @mock_logs
 @mock_ec2
 @mock_ecs