slice converted to single value

mapstructure.go

@@ -571,7 +571,11 @@ func (d *Decoder) decodeString(name string, data interface{}, val reflect.Value)
 			}
 			val.SetString(string(uints))
 		default:
-			converted = false
+			if dataVal.Len() == 1 {
+				return d.decodeString(name, dataVal.Index(0).Interface(), val)
+			} else {
+				converted = false
+			}
 		}
 	default:
 		converted = false
@@ -624,6 +628,15 @@ func (d *Decoder) decodeInt(name string, data interface{}, val reflect.Value) er
 				"error decoding json.Number into %s: %s", name, err)
 		}
 		val.SetInt(i)
+	case dataKind == reflect.Slice && d.config.WeaklyTypedInput,
+		dataKind == reflect.Array && d.config.WeaklyTypedInput:
+		if dataVal.Len() == 1 {
+			return d.decodeInt(name, dataVal.Index(0).Interface(), val)
+		} else {
+			return fmt.Errorf(
+				"'%s' expected type '%s', got unconvertible type '%s'",
+				name, val.Type(), dataVal.Type())
+		}
 	default:
 		return fmt.Errorf(
 			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",
@@ -685,6 +698,15 @@ func (d *Decoder) decodeUint(name string, data interface{}, val reflect.Value) e
 				name, i)
 		}
 		val.SetUint(uint64(i))
+	case dataKind == reflect.Slice && d.config.WeaklyTypedInput,
+		dataKind == reflect.Array && d.config.WeaklyTypedInput:
+		if dataVal.Len() == 1 {
+			return d.decodeUint(name, dataVal.Index(0).Interface(), val)
+		} else {
+			return fmt.Errorf(
+				"'%s' expected type '%s', got unconvertible type '%s'",
+				name, val.Type(), dataVal.Type())
+		}
 	default:
 		return fmt.Errorf(
 			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",
@@ -716,6 +738,15 @@ func (d *Decoder) decodeBool(name string, data interface{}, val reflect.Value) e
 		} else {
 			return fmt.Errorf("cannot parse '%s' as bool: %s", name, err)
 		}
+	case dataKind == reflect.Slice && d.config.WeaklyTypedInput,
+		dataKind == reflect.Array && d.config.WeaklyTypedInput:
+		if dataVal.Len() == 1 {
+			return d.decodeBool(name, dataVal.Index(0).Interface(), val)
+		} else {
+			return fmt.Errorf(
+				"'%s' expected type '%s', got unconvertible type '%s'",
+				name, val.Type(), dataVal.Type())
+		}
 	default:
 		return fmt.Errorf(
 			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",
@@ -763,6 +794,15 @@ func (d *Decoder) decodeFloat(name string, data interface{}, val reflect.Value)
 				"error decoding json.Number into %s: %s", name, err)
 		}
 		val.SetFloat(i)
+	case dataKind == reflect.Slice && d.config.WeaklyTypedInput,
+		dataKind == reflect.Array && d.config.WeaklyTypedInput:
+		if dataVal.Len() == 1 {
+			return d.decodeFloat(name, dataVal.Index(0).Interface(), val)
+		} else {
+			return fmt.Errorf(
+				"'%s' expected type '%s', got unconvertible type '%s'",
+				name, val.Type(), dataVal.Type())
+		}
 	default:
 		return fmt.Errorf(
 			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",

mapstructure_test.go

@@ -201,6 +201,10 @@ type TypeConversionResult struct {
 	StringToIntSlice   []int
 	StringToStrArray   [1]string
 	StringToIntArray   [1]int
+	SliceToString      string
+	SliceToInt64       int64
+	SliceToTrue        bool
+	SliceToFalse       bool
 	SliceToMap         map[string]interface{}
 	MapToSlice         []interface{}
 	ArrayToMap         map[string]interface{}
@@ -1090,6 +1094,10 @@ func TestDecode_TypeConversion(t *testing.T) {
 		"StringToIntSlice":   "42",
 		"StringToStrArray":   "A",
 		"StringToIntArray":   "42",
+		"SliceToString":      []string{"42"},
+		"SliceToInt64":       []string{"42"},
+		"SliceToTrue":        []string{"true"},
+		"SliceToFalse":       []string{""},
 		"SliceToMap":         []interface{}{},
 		"MapToSlice":         map[string]interface{}{},
 		"ArrayToMap":         []interface{}{},
@@ -1136,6 +1144,10 @@ func TestDecode_TypeConversion(t *testing.T) {
 		StringToIntSlice:   []int{42},
 		StringToStrArray:   [1]string{"A"},
 		StringToIntArray:   [1]int{42},
+		SliceToString:      "42",
+		SliceToInt64:       42,
+		SliceToTrue:        true,
+		SliceToFalse:       false,
 		SliceToMap:         map[string]interface{}{},
 		MapToSlice:         []interface{}{},
 		ArrayToMap:         map[string]interface{}{},