fix: handle length more robustly

frappe/core/doctype/docfield/docfield.json

@@ -11,8 +11,8 @@
   "label",
   "fieldtype",
   "fieldname",
-  "precision",
   "length",
+  "precision",
   "non_negative",
   "hide_days",
   "hide_seconds",
@@ -135,7 +135,7 @@
   },
   {
    "depends_on": "eval:in_list([\"Float\", \"Currency\", \"Percent\"], doc.fieldtype)",
-   "description": "Set non-standard precision for a Float or Currency field",
+   "description": "Set non-standard precision for a Float, Currency or Percent field",
    "fieldname": "precision",
    "fieldtype": "Select",
    "label": "Precision",
@@ -614,7 +614,7 @@
  "index_web_pages_for_search": 1,
  "istable": 1,
  "links": [],
- "modified": "2025-09-03 14:40:20.813091",
+ "modified": "2025-09-17 13:20:57.852396",
  "modified_by": "Administrator",
  "module": "Core",
  "name": "DocField",

frappe/core/doctype/doctype/doctype.py

@@ -1660,6 +1660,22 @@ def validate_fields(meta: Meta):
 			if docfield.options and (int(docfield.options) > 10 or int(docfield.options) < 3):
 				frappe.throw(_("Options for Rating field can range from 3 to 10"))
 
+	def check_decimal_config(docfield):
+		if docfield.fieldtype not in ("Currency", "Float", "Percent"):
+			return
+
+		if docfield.length and docfield.precision:
+			if cint(docfield.precision) > cint(docfield.length):
+				frappe.throw(
+					_("Precision ({0}) for {1} cannot be greater than its length ({2}).").format(
+						docfield.precision, frappe.bold(docfield.label), docfield.length
+					)
+				)
+
+		precision_not_set = docfield.precision in (None, "")
+		if docfield.length and precision_not_set and cint(docfield.length) < 9:  # default is 9
+			docfield.precision = docfield.length
+
 	fields = meta.get("fields")
 	fieldname_list = [d.fieldname for d in fields]
 
@@ -1682,6 +1698,7 @@ def validate_fields(meta: Meta):
 		scrub_options_in_select(d)
 		validate_fetch_from(d)
 		validate_data_field_type(d)
+		check_decimal_config(d)
 
 		if not frappe.flags.in_migrate or in_ci:
 			check_unique_fieldname(meta.get("name"), d.fieldname)

frappe/database/schema.py

@@ -432,7 +432,7 @@ def get_definition(fieldtype, precision=None, length=None, *, options=None):
 		# This check needs to exist for backward compatibility.
 		# Till V13, default size used for float, currency and percent are (18, 6).
 		if fieldtype in ["Float", "Currency", "Percent"] and cint(precision) > 6:
-			size = "21,9"
+			size = f"21,{cint(precision)}"
 
 		if length:
 			if coltype == "varchar":
@@ -443,7 +443,9 @@ def get_definition(fieldtype, precision=None, length=None, *, options=None):
 				# in postgres as bigint (as seen in type_map)
 				size = length
 			elif coltype == "decimal":
-				size = f"{length},9"
+				max_possible_precision = min(9, length)
+				precision = max_possible_precision if precision in (None, "") else cint(precision)
+				size = f"{length},{precision}"
 
 	if size is not None:
 		coltype = f"{coltype}({size})"