handling edge cases

src/troute-config/troute/config/output_parameters.py

@@ -1,6 +1,6 @@
 from pathlib import Path
 from pydantic import BaseModel, Field, validator
-import os
+
 from typing import Optional, List
 from typing_extensions import Annotated, Literal
 from .types import FilePath, DirectoryPath
@@ -93,17 +93,25 @@ class ParityCheckCompareFileSet(BaseModel):
 
 class StreamOutput(BaseModel):
     # NOTE: required if writing StreamOutput files
-    stream_output_directory: Optional[str] = None
+    stream_output_directory: Optional[Path] = None
     mask_output: Optional[FilePath] = None
     stream_output_time: int = 1
     stream_output_type:streamOutput_allowedTypes = ".nc"
     stream_output_internal_frequency: Annotated[int, Field(strict=True, ge=5)] = 5
 
-    @validator('stream_output_directory', pre=True, always=True)
+    @validator('stream_output_directory')
     def validate_stream_output_directory(cls, value):
-        if value:
-            if not os.path.exists(value):
-                os.makedirs(value) 
+        if value is None:
+            return None
+
+        # expand ~/output/dir -> /home/user/output/dir
+        value = value.expanduser()
+
+        if value.exists() and not value.is_dir():
+            raise ValueError(f"'stream_output_directory'={value!s} is a file, expected directory.")
+
+        # make directory (and intermediates) if they don't exist
+        value.mkdir(parents=True, exist_ok=True)
         return value
 
     @validator('stream_output_internal_frequency')