Patch/sequence field singleton

decode.go

@@ -712,6 +712,13 @@ func (d *decoder) scalar(n *Node, out reflect.Value) bool {
 			out.Set(resolvedv)
 			return true
 		}
+	case reflect.Slice, reflect.Array:
+		// This (likely) indicates the source value is a sequence with only a singular value (e.g. want `field: [a, b, c]`, got `field: a`),
+		// but does not match the expected "clues" to fully identify it as a sequence. Attempt to "re-class" the node as a sequence
+		// and process it as such.
+		n.Kind = SequenceNode
+		n.Content = []*Node{{Kind: ScalarNode, Value: n.Value}}
+		return d.sequence(n, out)
 	case reflect.Ptr:
 		panic("yaml internal error: please report the issue")
 	}

decode_test.go

@@ -219,7 +219,10 @@ var unmarshalTests = []struct {
 	}, {
 		"seq: [A,1,C]",
 		map[string]interface{}{"seq": []interface{}{"A", 1, "C"}},
-	},
+	}, /*{
+		"seq: [A]",
+		map[string]string{"seq": "A"},
+	},*/
 	// Block sequence
 	{
 		"seq:\n - A\n - B",
@@ -947,7 +950,7 @@ var unmarshalErrorTests = []struct {
 	{"%TAG !%79! tag:yaml.org,2002:\n---\nv: !%79!int '1'", "yaml: did not find expected whitespace"},
 	{"a:\n  1:\nb\n  2:", ".*could not find expected ':'"},
 	{"a: 1\nb: 2\nc 2\nd: 3\n", "^yaml: line 3: could not find expected ':'$"},
-	{"#\n-\n{", "yaml: line 3: could not find expected ':'"}, // Issue #665
+	{"#\n-\n{", "yaml: line 3: could not find expected ':'"},   // Issue #665
 	{"0: [:!00 \xef", "yaml: incomplete UTF-8 octet sequence"}, // Issue #666
 	{
 		"a: &a [00,00,00,00,00,00,00,00,00]\n" +
@@ -1482,7 +1485,7 @@ func (s *S) TestMergeNestedStruct(c *C) {
 	// 2) A simple implementation might attempt to handle the key skipping
 	//    directly by iterating over the merging map without recursion, but
 	//    there are more complex cases that require recursion.
-	// 
+	//
 	// Quick summary of the fields:
 	//
 	// - A must come from outer and not overriden
@@ -1498,7 +1501,7 @@ func (s *S) TestMergeNestedStruct(c *C) {
 		A, B, C int
 	}
 	type Outer struct {
-		D, E      int
+		D, E   int
 		Inner  Inner
 		Inline map[string]int `yaml:",inline"`
 	}
@@ -1516,10 +1519,10 @@ func (s *S) TestMergeNestedStruct(c *C) {
 	// Repeat test with a map.
 
 	var testm map[string]interface{}
-	var wantm = map[string]interface {} {
-		"f":     60,
+	var wantm = map[string]interface{}{
+		"f": 60,
 		"inner": map[string]interface{}{
-		    "a": 10,
+			"a": 10,
 		},
 		"d": 40,
 		"e": 50,

go.mod

@@ -1,5 +1,10 @@
-module "gopkg.in/yaml.v3"
+module gopkg.in/yaml.v3
+
+go 1.20
+
+require gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c
 
 require (
-	"gopkg.in/check.v1" v0.0.0-20161208181325-20d25e280405
+	github.com/kr/pretty v0.2.1 // indirect
+	github.com/kr/text v0.1.0 // indirect
 )