[Fruiterer333]

Link to Issue or Description of Change

1. Link to an existing issue (if applicable):

• Closes: ExecuteBashTool ignores resource limits that are set to 0 #7983
  Problem:

_set_resource_limits checked each limit with if policy.max_file_size_bytes:. A limit of 0 is falsy, so setrlimit was never called for it and the command ran with no limit. BashToolPolicy(max_file_size_bytes=0) let a command write files of any size, and max_child_processes=0 did not stop it from starting child processes.

Solution:

The three limits are now checked with is not None. None is still the default and still means no limit; 0 is now passed to setrlimit like any other value. The BashToolPolicy docstring now says that 0 is enforced.

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.

• All unit tests pass locally.
  Added two tests to tests/unittests/tools/test_bash_tool.py; both fail on main:

• test_zero_resource_limits_are_enforced: with all three limits at 0, setrlimit is called for RLIMIT_AS, RLIMIT_FSIZE and RLIMIT_NPROC with (0, 0).

• test_zero_file_size_limit_blocks_file_writes: with max_file_size_bytes=0, a real dd command that writes 4096 bytes fails and the file stays empty.

$ pytest tests/unittests/tools/test_bash_tool.py
28 passed

Manual End-to-End (E2E) Tests:

Ran the reproduction script from the issue:

# before (main)
max_file_size_bytes=1024: returncode=-25, bytes written=1024
max_file_size_bytes=0: returncode=0, bytes written=4096
 
# after
max_file_size_bytes=1024: returncode=-25, bytes written=1024
max_file_size_bytes=0: returncode=-25, bytes written=0

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have manually tested my changes end-to-end.
• Any dependent changes have been merged and published in downstream modules. (N/A: no dependent changes)

Additional context

I used Claude Code to help find the issue and draft the change; I reproduced the bug and verified the fix and tests locally.