bug: all IntegrityErrors are reported as unique constraint violations during model creation/update

[shrouxm]

Description

Currently any integrity error that occurs when trying to save a model to the database is reported as a unique constraint violation, when it could be for other reasons (one I have encountered is supplying NULL to a non-nullable field). Relevant code here:

terraso-backend/terraso_backend/apps/graphql/schema/commons.py

Lines 211 to 231 in f16af3e

	try:
	model_instance.save()
	except IntegrityError as exc:
	logger.info(
	"Attempt to mutate an model, but it's not unique",
	extra={"model": cls.model_class.__name__, "integrity_error": exc},
	)
	# It's not trivial identify the exact field(s) that originated the integrity errror
	# here, so we identify the error as NON_FIELD_ERROR with the unique code.
	validation_error = ValidationError(
	message={
	NON_FIELD_ERRORS: ValidationError(
	message=f"This {cls.model_class.__name__} already exists",
	code="unique",
	)
	},
	)
	raise GraphQLValidationException.from_validation_error(
	validation_error, model_name=cls.model_class.__name__
	)

Expected behavior

Integrity errors report the actual error which occurred.

Actual behavior

We always report a unique constraint violation.