feat: Add Windows PowerShell support to CLI runtime (#9211)

Co-authored-by: openhands <openhands@all-hands.dev>

openhands/runtime/utils/windows_bash.py

@@ -21,21 +21,31 @@ from openhands.events.observation.commands import (
     CmdOutputObservation,
 )
 from openhands.runtime.utils.bash_constants import TIMEOUT_MESSAGE_TEMPLATE
+from openhands.runtime.utils.windows_exceptions import DotNetMissingError
 from openhands.utils.shutdown_listener import should_continue
 
-pythonnet.load('coreclr')
-logger.info("Successfully called pythonnet.load('coreclr')")
-
-# Now that pythonnet is initialized, import clr and System
 try:
-    import clr
+    pythonnet.load('coreclr')
+    logger.info("Successfully called pythonnet.load('coreclr')")
 
-    logger.debug(f'Imported clr module from: {clr.__file__}')
-    # Load System assembly *after* pythonnet is initialized
-    clr.AddReference('System')
-    import System
-except Exception as clr_sys_ex:
-    raise RuntimeError(f'FATAL: Failed to import clr or System. Error: {clr_sys_ex}')
+    # Now that pythonnet is initialized, import clr and System
+    try:
+        import clr
+
+        logger.debug(f'Imported clr module from: {clr.__file__}')
+        # Load System assembly *after* pythonnet is initialized
+        clr.AddReference('System')
+        import System
+    except Exception as clr_sys_ex:
+        error_msg = 'Failed to import .NET components.'
+        details = str(clr_sys_ex)
+        logger.error(f'{error_msg} Details: {details}')
+        raise DotNetMissingError(error_msg, details)
+except Exception as coreclr_ex:
+    error_msg = 'Failed to load CoreCLR.'
+    details = str(coreclr_ex)
+    logger.error(f'{error_msg} Details: {details}')
+    raise DotNetMissingError(error_msg, details)
 
 # Attempt to load the PowerShell SDK assembly only if clr and System loaded
 ps_sdk_path = None
@@ -78,9 +88,10 @@ try:
         RunspaceState,
     )
 except Exception as e:
-    raise RuntimeError(
-        f'FATAL: Failed to load PowerShell SDK components. Error: {e}. Check pythonnet installation and .NET Runtime compatibility. Path searched: {ps_sdk_path}'
-    )
+    error_msg = 'Failed to load PowerShell SDK components.'
+    details = f'{str(e)} (Path searched: {ps_sdk_path})'
+    logger.error(f'{error_msg} Details: {details}')
+    raise DotNetMissingError(error_msg, details)
 
 
 class WindowsPowershellSession:
@@ -115,9 +126,11 @@ class WindowsPowershellSession:
 
         if PowerShell is None:  # Check if SDK loading failed during module import
             # Logged critical error during import, just raise here to prevent instantiation
-            raise RuntimeError(
-                'PowerShell SDK (System.Management.Automation.dll) could not be loaded. Cannot initialize WindowsPowershellSession.'
+            error_msg = (
+                'PowerShell SDK (System.Management.Automation.dll) could not be loaded.'
             )
+            logger.error(error_msg)
+            raise DotNetMissingError(error_msg)
 
         self.work_dir = os.path.abspath(work_dir)
         self.username = username

openhands/runtime/utils/windows_exceptions.py

@@ -0,0 +1,15 @@
+"""
+Custom exceptions for Windows-specific runtime issues.
+"""
+
+
+class DotNetMissingError(Exception):
+    """
+    Exception raised when .NET SDK or CoreCLR is missing or cannot be loaded.
+    This is used to provide a cleaner error message to users without a full stack trace.
+    """
+
+    def __init__(self, message: str, details: str | None = None):
+        self.message = message
+        self.details = details
+        super().__init__(message)