[Qrytics]

What

prepare_cmd_args() in bin/awslocal aliased the live sys.argv list (cmd_args = sys.argv) and then insert()ed --endpoint-url into it. Every call mutated the process's real argv, so a second call stacked a duplicate --endpoint-url flag (and run_as_separate_process's later cmd_args[0] = 'aws' rewrite also leaked into sys.argv).

Fix

Work on a copy — cmd_args = list(sys.argv) — so the inserts/rewrites never touch sys.argv. Single-call behavior is identical; repeated calls are now stable.

Tests

New tests/test_awslocal_prepare_cmd_args.py (loads bin/awslocal via SourceFileLoader with a stubbed localstack_client):

• test_prepare_cmd_args_inserts_endpoint_once — passes before and after.
• test_prepare_cmd_args_is_repeatable — fails before (second call returns two --endpoint-url flags), passes after; also asserts sys.argv itself stays clean.

python -m pytest tests/test_awslocal_prepare_cmd_args.py -q
2 passed