fix: change DisallowUnknownFields error from "missing field" to "unknown field" (#1054)

Yanhu007 · web-flow · commit 45d4fb4b82a9 · 2026-04-16T14:50:12.000-04:00
The diagnostic message for DisallowUnknownFields said "missing field", which reads as if the TOML is missing something required. From the user's perspective, the field is unknown to the target struct. Change the message to "unknown field" for consistency with the DisallowUnknownFields API name and to reduce confusion. Fixes #1049
diff --git a/strict.go b/strict.go
@@ -68,7 +68,7 @@ func (s *strict) MissingField(node *unstable.Node) {
 
 	s.missing = append(s.missing, unstable.ParserError{
 		Highlight: s.keyLocation(node),
-		Message:   "missing field",
+		Message:   "unknown field",
 		Key:       s.key.Key(),
 	})
 }
diff --git a/unmarshaler_test.go b/unmarshaler_test.go
@@ -65,7 +65,7 @@ key3 = "value3"
 	// strict mode: fields in the document are missing in the target struct
 	// 2| key1 = "value1"
 	// 3| key2 = "value2"
-	//  | ~~~~ missing field
+	//  | ~~~~ unknown field
 	// 4| key3 = "value3"
 }
 
@@ -2387,14 +2387,14 @@ key4 = "value4"
 `,
 			expected: `2| key1 = "value1"
 3| key2 = "missing2"
- | ~~~~ missing field
+ | ~~~~ unknown field
 4| key3 = "missing3"
 5| key4 = "value4"
 ---
 2| key1 = "value1"
 3| key2 = "missing2"
 4| key3 = "missing3"
- | ~~~~ missing field
+ | ~~~~ unknown field
 5| key4 = "value4"`,
 			target: &struct {
 				Key1 string
@@ -2405,7 +2405,7 @@ key4 = "value4"
 			desc:  "multi-part key",
 			input: `a.short.key="foo"`,
 			expected: `1| a.short.key="foo"
- | ~~~~~~~~~~~ missing field`,
+ | ~~~~~~~~~~~ unknown field`,
 		},
 		{
 			desc: "missing table",

Original file line number	Diff line number	Diff line change
`@@ -68,7 +68,7 @@ func (s strict) MissingField(node unstable.Node) {`
`68`	`68`
`69`	`69`	`s.missing = append(s.missing, unstable.ParserError{`
`70`	`70`	`Highlight: s.keyLocation(node),`
`71`		`- Message: "missing field",`
	`71`	`+ Message: "unknown field",`
`72`	`72`	`Key: s.key.Key(),`
`73`	`73`	`})`
`74`	`74`	`}`