fix(env): run local commands through bash

src/minisweagent/environments/local.py

@@ -14,6 +14,8 @@ class LocalEnvironmentConfig(BaseModel):
     cwd: str = ""
     env: dict[str, str] = {}
     timeout: int = 30
+    interpreter: list[str] = ["bash", "-lc"]
+    """Interpreter to use to execute commands. The command is appended as the final argument."""
 
 
 class LocalEnvironment:
@@ -26,7 +28,9 @@ def execute(self, action: dict, cwd: str = "", *, timeout: int | None = None) ->
         command = action.get("command", "")
         cwd = cwd or self.config.cwd or os.getcwd()
         try:
-            result = _run(command, cwd, os.environ | self.config.env, timeout or self.config.timeout)
+            result = _run(
+                command, cwd, os.environ | self.config.env, timeout or self.config.timeout, self.config.interpreter
+            )
             output = {"output": result.stdout, "returncode": result.returncode, "exception_info": ""}
         except Exception as e:
             raw_output = getattr(e, "output", None)
@@ -69,11 +73,12 @@ def serialize(self) -> dict:
         }
 
 
-def _run(command: str, cwd: str, env: dict[str, str], timeout: int) -> subprocess.CompletedProcess[str]:
+def _run(
+    command: str, cwd: str, env: dict[str, str], timeout: int, interpreter: list[str]
+) -> subprocess.CompletedProcess[str]:
     """Like subprocess.run, but kills the whole process group on timeout so no children are orphaned."""
     process = subprocess.Popen(
-        command,
-        shell=True,
+        [*interpreter, command],
         text=True,
         cwd=cwd,
         env=env,

tests/environments/test_local.py

@@ -19,6 +19,7 @@ def test_local_environment_config_defaults():
     assert config.cwd == ""
     assert config.env == {}
     assert config.timeout == 30
+    assert config.interpreter == ["bash", "-lc"]
 
 
 def test_local_environment_basic_execution():
@@ -262,3 +263,13 @@ def test_local_environment_shell_features():
     result = env.execute({"command": "echo $(echo 'nested')"})
     assert result["returncode"] == 0
     assert "nested" in result["output"]
+
+
+@pytest.mark.skipif(os.name == "nt", reason="requires bash")
+def test_local_environment_uses_bash_by_default():
+    """Test that the local environment supports bash-only syntax by default."""
+    env = LocalEnvironment()
+
+    result = env.execute({"command": "cat <(printf 'bash-only')"})
+    assert result["returncode"] == 0
+    assert result["output"] == "bash-only"