fix issue740: parse colon in plain scalar correctly

src/exp.h

@@ -164,8 +164,7 @@ inline const RegEx& EndScalar() {
 }
 inline const RegEx& EndScalarInFlow() {
   static const RegEx e =
-      (RegEx(':') + (BlankOrBreak() | RegEx() | RegEx(",]}", REGEX_OR))) |
+      (RegEx(':') + (BlankOrBreak() | RegEx())) | RegEx(",?[]{}", REGEX_OR);
-      RegEx(",?[]{}", REGEX_OR);
   return e;
 }
 

test/integration/load_node_test.cpp

@@ -265,6 +265,50 @@ TEST(NodeTest, IncompleteJson) {
   }
 }
 
+struct SingleNodeTestCase {
+  std::string input;
+  NodeType::value nodeType;
+  int nodeSize;
+  std::string expected_content;
+};
+
+TEST(NodeTest, SpecialFlow) {
+  std::vector<SingleNodeTestCase> tests = {
+    {"[,]", NodeType::Sequence, 1, "[~]"},
+    {"[a:]", NodeType::Sequence, 1, "[\"a:\"]"},
+    {"[:a]", NodeType::Sequence, 1, "[:a]"},
+    {"[:]", NodeType::Sequence, 1, "[\":\"]"},
+    {"{:}", NodeType::Map, 1, "{~: ~}"},
+    {"{,}", NodeType::Map, 1, "{~: ~}"},
+    {"{a:}", NodeType::Map, 1, "{\"a:\": ~}"},
+    {"{:a}", NodeType::Map, 1, "{:a: ~}"},
+  };
+  for (const SingleNodeTestCase& test : tests) {
+    Node node = Load(test.input);
+    Emitter emitter;
+    emitter << node;
+    EXPECT_EQ(test.nodeType, node.Type());
+    EXPECT_EQ(test.nodeSize, node.size());
+    EXPECT_EQ(test.expected_content, std::string(emitter.c_str()));
+  }
+}
+
+TEST(NodeTest, IncorrectFlow) {
+  std::vector<ParserExceptionTestCase> tests = {
+    {"Incorrect yaml: \"{:]\"", "{:]", ErrorMsg::FLOW_END},
+    {"Incorrect yaml: \"[:}\"", "[:}", ErrorMsg::FLOW_END},
+  };
+  for (const ParserExceptionTestCase test : tests) {
+    try {
+      Load(test.input);
+      FAIL() << "Expected exception " << test.expected_exception << " for "
+             << test.name << ", input: " << test.input;
+    } catch (const ParserException& e) {
+      EXPECT_EQ(test.expected_exception, e.msg);
+    }
+  }
+}
+
 TEST(NodeTest, LoadTildeAsNull) {
   Node node = Load("~");
   ASSERT_TRUE(node.IsNull());