allow plain scalars with colons inside flow mappings and sequences

We copy the same fix from the original libyaml code.

Fixes issue #295.

decode_test.go

@@ -513,6 +513,18 @@ var unmarshalTests = []struct {
 		map[string]interface{}{"a": "50cent_of_dollar"},
 	},
 
+	// issue #295 (allow scalars with colons in flow mappings and sequences)
+	{
+		"a: {b: https://github.com/go-yaml/yaml}",
+		map[string]interface{}{"a": map[interface{}]interface{}{
+			"b": "https://github.com/go-yaml/yaml",
+		}},
+	},
+	{
+		"a: [https://github.com/go-yaml/yaml]",
+		map[string]interface{}{"a": []interface{}{"https://github.com/go-yaml/yaml"}},
+	},
+
 	// Duration
 	{
 		"a: 3s",

scannerc.go

@@ -2592,19 +2592,10 @@ func yaml_parser_scan_plain_scalar(parser *yaml_parser_t, token *yaml_token_t) b
 		// Consume non-blank characters.
 		for !is_blankz(parser.buffer, parser.buffer_pos) {
 
-			// Check for 'x:x' in the flow context. TODO: Fix the test "spec-08-13".
-			if parser.flow_level > 0 &&
-				parser.buffer[parser.buffer_pos] == ':' &&
-				!is_blankz(parser.buffer, parser.buffer_pos+1) {
-				yaml_parser_set_scanner_error(parser, "while scanning a plain scalar",
-					start_mark, "found unexpected ':'")
-				return false
-			}
-
 			// Check for indicators that may end a plain scalar.
 			if (parser.buffer[parser.buffer_pos] == ':' && is_blankz(parser.buffer, parser.buffer_pos+1)) ||
 				(parser.flow_level > 0 &&
-					(parser.buffer[parser.buffer_pos] == ',' || parser.buffer[parser.buffer_pos] == ':' ||
+					(parser.buffer[parser.buffer_pos] == ',' ||
 						parser.buffer[parser.buffer_pos] == '?' || parser.buffer[parser.buffer_pos] == '[' ||
 						parser.buffer[parser.buffer_pos] == ']' || parser.buffer[parser.buffer_pos] == '{' ||
 						parser.buffer[parser.buffer_pos] == '}')) {