From baaeb5da4f5bd2b20fb8cd9fe331512840148946 Mon Sep 17 00:00:00 2001
From: Inteon <42113979+inteon@users.noreply.github.com>
Date: Sun, 31 Oct 2021 12:03:46 +0100
Subject: [PATCH] consider 'unknown field' errors to be strict errors

Signed-off-by: Inteon <42113979+inteon@users.noreply.github.com>
---
 decode.go      | 13 ++++++++-----
 decode_test.go | 12 ++++++++----
 yaml.go        | 17 +++++++++--------
 3 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/decode.go b/decode.go
index df36e3a3..8ccf115d 100644
--- a/decode.go
+++ b/decode.go
@@ -308,9 +308,10 @@ func (p *parser) mapping() *Node {
 // Decoder, unmarshals a node into a provided value.
 
 type decoder struct {
-	doc     *Node
-	aliases map[*Node]bool
-	terrors []string
+	doc          *Node
+	aliases      map[*Node]bool
+	terrors      []string
+	strictErrors []string
 
 	stringMapType  reflect.Type
 	generalMapType reflect.Type
@@ -361,6 +362,7 @@ func (d *decoder) callUnmarshaler(n *Node, u Unmarshaler) (good bool) {
 	err := u.UnmarshalYAML(n)
 	if e, ok := err.(*TypeError); ok {
 		d.terrors = append(d.terrors, e.Errors...)
+		d.strictErrors = append(d.strictErrors, e.StrictErrors...)
 		return false
 	}
 	if err != nil {
@@ -377,12 +379,13 @@ func (d *decoder) callObsoleteUnmarshaler(n *Node, u obsoleteUnmarshaler) (good
 		if len(d.terrors) > terrlen {
 			issues := d.terrors[terrlen:]
 			d.terrors = d.terrors[:terrlen]
-			return &TypeError{issues}
+			return &TypeError{issues, nil}
 		}
 		return nil
 	})
 	if e, ok := err.(*TypeError); ok {
 		d.terrors = append(d.terrors, e.Errors...)
+		d.strictErrors = append(d.strictErrors, e.StrictErrors...)
 		return false
 	}
 	if err != nil {
@@ -908,7 +911,7 @@ func (d *decoder) mappingStruct(n *Node, out reflect.Value) (good bool) {
 			d.unmarshal(n.Content[i+1], value)
 			inlineMap.SetMapIndex(name, value)
 		} else if d.knownFields {
-			d.terrors = append(d.terrors, fmt.Sprintf("line %d: field %s not found in type %s", ni.Line, name.String(), out.Type()))
+			d.strictErrors = append(d.strictErrors, fmt.Sprintf("line %d: field %s not found in type %s", ni.Line, name.String(), out.Type()))
 		}
 	}
 	return true
diff --git a/decode_test.go b/decode_test.go
index a5dfadca..5142d13b 100644
--- a/decode_test.go
+++ b/decode_test.go
@@ -1110,8 +1110,8 @@ func (s *S) TestUnmarshalerWholeDocument(c *C) {
 }
 
 func (s *S) TestUnmarshalerTypeError(c *C) {
-	unmarshalerResult[2] = &yaml.TypeError{[]string{"foo"}}
-	unmarshalerResult[4] = &yaml.TypeError{[]string{"bar"}}
+	unmarshalerResult[2] = &yaml.TypeError{[]string{"foo"}, nil}
+	unmarshalerResult[4] = &yaml.TypeError{[]string{"bar"}, nil}
 	defer func() {
 		delete(unmarshalerResult, 2)
 		delete(unmarshalerResult, 4)
@@ -1141,8 +1141,8 @@ func (s *S) TestUnmarshalerTypeError(c *C) {
 }
 
 func (s *S) TestObsoleteUnmarshalerTypeError(c *C) {
-	unmarshalerResult[2] = &yaml.TypeError{[]string{"foo"}}
-	unmarshalerResult[4] = &yaml.TypeError{[]string{"bar"}}
+	unmarshalerResult[2] = &yaml.TypeError{[]string{"foo"}, nil}
+	unmarshalerResult[4] = &yaml.TypeError{[]string{"bar"}, nil}
 	defer func() {
 		delete(unmarshalerResult, 2)
 		delete(unmarshalerResult, 4)
@@ -1605,6 +1605,10 @@ func (s *S) TestUnmarshalKnownFields(c *C) {
 		dec.KnownFields(item.known)
 		err := dec.Decode(value.Interface())
 		c.Assert(err, ErrorMatches, item.error)
+		if !item.unique {
+			// If a strict error occurs, the decoding should still be successful
+			c.Assert(value.Elem().Interface(), DeepEquals, item.value)
+		}
 	}
 }
 
diff --git a/yaml.go b/yaml.go
index 3ba221c2..0156aa61 100644
--- a/yaml.go
+++ b/yaml.go
@@ -129,8 +129,8 @@ func (dec *Decoder) Decode(v interface{}) (err error) {
 		out = out.Elem()
 	}
 	d.unmarshal(node, out)
-	if len(d.terrors) > 0 {
-		return &TypeError{d.terrors}
+	if len(d.terrors) > 0 || len(d.strictErrors) > 0 {
+		return &TypeError{d.terrors, d.strictErrors}
 	}
 	return nil
 }
@@ -147,8 +147,8 @@ func (n *Node) Decode(v interface{}) (err error) {
 		out = out.Elem()
 	}
 	d.unmarshal(n, out)
-	if len(d.terrors) > 0 {
-		return &TypeError{d.terrors}
+	if len(d.terrors) > 0 || len(d.strictErrors) > 0 {
+		return &TypeError{d.terrors, d.strictErrors}
 	}
 	return nil
 }
@@ -166,8 +166,8 @@ func unmarshal(in []byte, out interface{}, strict bool) (err error) {
 		}
 		d.unmarshal(node, v)
 	}
-	if len(d.terrors) > 0 {
-		return &TypeError{d.terrors}
+	if len(d.terrors) > 0 || len(d.strictErrors) > 0 {
+		return &TypeError{d.terrors, d.strictErrors}
 	}
 	return nil
 }
@@ -313,11 +313,12 @@ func failf(format string, args ...interface{}) {
 // types. When this error is returned, the value is still
 // unmarshaled partially.
 type TypeError struct {
-	Errors []string
+	Errors       []string
+	StrictErrors []string
 }
 
 func (e *TypeError) Error() string {
-	return fmt.Sprintf("yaml: unmarshal errors:\n  %s", strings.Join(e.Errors, "\n  "))
+	return fmt.Sprintf("yaml: unmarshal errors:\n  %s", strings.Join(append(e.Errors, e.StrictErrors...), "\n  "))
 }
 
 type Kind uint32