With use_strict enabled, configured output files fail Pydantic validation

[program--]

Current Behavior

When chanobs_filepath is defined in a t-route configuration file, executing Config.with_strict_mode(...) results in a Pydantic validation error.

Expected Behavior

Using with_strict_mode shouldn't raise a file not found validation error on output files.

Details

In NOAA-OWP/ngen our t-route integration tests have started failing due to the Chanobs.nc file not existing. My understanding is that this is an output file, so it shouldn't necessarily exist until after t-route has executed.

• Backtracing the error, it starts with strict mode being enabled for config parsing with d443337.
• Looking in troute-config, chanobs_filepath has type FilePath
  

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

  Line 38 in ae6a7b1

  chanobs_filepath: Optional[FilePath] = None

  
  and FilePath is defined as
  

  t-route/src/troute-config/troute/config/types.py

  Lines 15 to 32 in ae6a7b1

  	class FilePath(PydanticFilePath):
  	"""
  	Coerce into a `pathlib.Path` type. If strict mode is enabled (see _utils.use_strict), will raise
  	if file does not exist.
  	"""
  	@classmethod
  	def __get_validators__(cls) -> "CallableGenerator":
  	yield cls.validate
  	@classmethod
  	def validate(cls, value: Path) -> Path:
  	if strict_set():
  	for validator in PydanticFilePath.__get_validators__():
  	value = validator(value)
  	return value
  	else:
  	return Path(value)

I think a slight semantic change is necessary, i.e. something like InputFilePath and OutputFilePath, where InputFilePath parameters are validated for existence in the same way that FilePath is, and OutputFilePath are validated only for write permissions in the parent directory but not existence.

Though, it's entirely possible I'm misunderstanding something, so please let me know if I am! 🙂