From 97f18c3339b4257d9f544e1c840c4c61d8e77444 Mon Sep 17 00:00:00 2001
From: Varun Nuthalapati <nuthalapativarun@gmail.com>
Date: Thu, 28 May 2026 23:20:49 -0700
Subject: [PATCH] fix: skip bash syntax validation on Windows

_validate_bash_command calls /bin/bash -n, which is absent on Windows.
This causes FileNotFoundError (or exit code 1) on every agent step,
raising FormatError for every valid command. Guard the subprocess call
with a sys.platform check and return early on win32.
---
 src/webwright/models/base.py       |  3 +++
 tests/unit/test_bash_validation.py | 39 ++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 tests/unit/test_bash_validation.py

diff --git a/src/webwright/models/base.py b/src/webwright/models/base.py
index 7728bb8..03d225d 100644
--- a/src/webwright/models/base.py
+++ b/src/webwright/models/base.py
@@ -6,6 +6,7 @@
 import mimetypes
 import os
 import subprocess
+import sys
 from pathlib import Path
 from typing import Annotated, Any
 
@@ -121,6 +122,8 @@ def parse_json_output(raw: str, *, action_field: str = "bash_command") -> dict[s
 
 
 def _validate_bash_command(command: str) -> None:
+    if sys.platform == "win32":
+        return
     result = subprocess.run(
         ["/bin/bash", "-n"],
         input=command,
diff --git a/tests/unit/test_bash_validation.py b/tests/unit/test_bash_validation.py
new file mode 100644
index 0000000..4051728
--- /dev/null
+++ b/tests/unit/test_bash_validation.py
@@ -0,0 +1,39 @@
+import sys
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from webwright.models.base import _validate_bash_command
+
+
+def _make_proc(returncode: int, stderr: str = "") -> MagicMock:
+    proc = MagicMock()
+    proc.returncode = returncode
+    proc.stderr = stderr
+    proc.stdout = ""
+    return proc
+
+
+def test_valid_command_passes_on_posix(monkeypatch) -> None:
+    monkeypatch.setattr(sys, "platform", "linux")
+    with patch("subprocess.run", return_value=_make_proc(0)):
+        _validate_bash_command("echo hello")
+
+
+def test_invalid_syntax_raises_on_posix(monkeypatch) -> None:
+    monkeypatch.setattr(sys, "platform", "linux")
+    with patch("subprocess.run", return_value=_make_proc(1, "syntax error near unexpected token")):
+        with pytest.raises(ValueError, match="Invalid bash_command syntax"):
+            _validate_bash_command("if then fi done ;;;")
+
+
+def test_validation_skipped_on_windows(monkeypatch) -> None:
+    monkeypatch.setattr(sys, "platform", "win32")
+    _validate_bash_command("if then fi done ;;;")
+
+
+def test_validation_skipped_on_windows_does_not_call_subprocess(monkeypatch) -> None:
+    monkeypatch.setattr(sys, "platform", "win32")
+    with patch("subprocess.run") as mock_run:
+        _validate_bash_command("echo hi")
+        mock_run.assert_not_called()