feat: set a non-null value if docfield isn't set as nullable

Signed-off-by: Akhil Narang <me@akhilnarang.dev>

frappe/model/base_document.py

@@ -31,6 +31,7 @@ from frappe.utils import (
 	sanitize_html,
 	strip_html,
 )
+from frappe.utils.defaults import get_not_null_defaults
 from frappe.utils.html_utils import unescape_html
 
 if TYPE_CHECKING:
@@ -384,6 +385,10 @@ class BaseDocument:
 			if ignore_nulls and not is_virtual_field and value is None:
 				continue
 
+			# If the docfield is not nullable - set a default non-null value
+			if value is None and getattr(df, "not_nullable", False):
+				value = get_not_null_defaults(df.fieldtype)
+
 			d[fieldname] = value
 
 		return d

frappe/utils/defaults.py

@@ -0,0 +1,50 @@
+from typing import Literal
+
+
+def get_not_null_defaults(column_type: str) -> Literal["", 0] | None:
+	"""
+	Method to return a default value for a column type that is not NoneType
+	:param column_type: The type of column
+	:return: The value to be set
+	"""
+	column_type_map = {
+		"Data": str,
+		"Text": str,
+		"Autocomplete": str,
+		"Attach": str,
+		"AttachImage": str,
+		"Barcode": str,
+		"Check": int,
+		"Code": str,
+		"Color": str,
+		"Currency": float,
+		"Date": str,
+		"Datetime": str,
+		"Duration": int,
+		"DynamicLink": str,
+		"Float": float,
+		"HTMLEditor": str,
+		"Int": int,
+		"JSON": str,
+		"Link": str,
+		"LongText": str,
+		"MarkdownEditor": str,
+		"Password": str,
+		"Percent": float,
+		"Phone": str,
+		"ReadOnly": str,
+		"Rating": float,
+		"Select": str,
+		"SmallText": str,
+		"TextEditor": str,
+		"Time": str,
+		"Table": list,
+		"Table MultiSelect": list,
+	}
+	data_type = column_type_map.get(column_type.replace(" ", ""), str)
+	# data_type = eval(f"frappe.types.DF.{column_type.replace(' ', '')}")
+	if data_type == str:
+		return ""
+	if data_type in (int, float):
+		return 0
+	return None