# YAML Test Matrix

--- &test-CTN5
  Title: Flow sequence with invalid extra comma
  Tags: [ error, flow, sequence ]

YAML

---
[ a, b, c, , ]

Expected Events

+STR
+DOC ---
+SEQ []
=VAL :a
=VAL :b
=VAL :c

Expected JSON



cpp-rapidyaml-event

 invalid_incorrect
+STR
+DOC ---
+SEQ
=VAL :a
=VAL :b
=VAL :c
=VAL :
-SEQ
-DOC
-STR

cpp-yamlcpp-event

 invalid_incorrect
+STR
+DOC
+SEQ []
=VAL :a
=VAL :b
=VAL :c
=VAL :
-SEQ
-DOC
-STR

hs-reference-yeast

 invalid_incorrect
Line  Col Char Byte Token|Content
   1    0    0    0 +DOC |
   1    0    0    0 =HEAD|---
   1    3    3    3 +NODE|
   1    3    3    3 +VAL |
   1    3    3    3 -VAL |
   1    3    3    3 -NODE|
   1    3    3    3 =EOL |\x0a
   2    0    4    4 =REST|[.a,.b,.c,.,.]
   2   14   18   18 =REST|\x0a
   3    0   19   19 -DOC |

nim-nimyaml-event

 invalid_incorrect
+STR
+DOC ---
+SEQ
=VAL :a
=VAL :b
=VAL :c
=VAL :
-SEQ
-DOC
-STR

c-libfyaml-event

 invalid_correct
stdin:2:12: error: flow sequence with invalid extra comma
[ a, b, c, , ]
           ^
+STR
+DOC ---
+SEQ []
=VAL :a
=VAL :b
=VAL :c

c-libfyaml-json

 invalid_correct
stdin:2:12: error: flow sequence with invalid extra comma
[ a, b, c, , ]
           ^

c-libyaml-event

 invalid_correct
Parse error: did not find expected node content
+STR
+DOC ---
+SEQ []
=VAL :a
=VAL :b
=VAL :c

dotnet-yamldotnet-event

 invalid_correct
Unhandled exception. YamlDotNet.Core.SemanticErrorException: (Line: 2, Col: 12, Idx: 15) - (Line: 2, Col: 13, Idx: 16): While parsing a node, did not find expected node content.
   at YamlDotNet.Core.Parser.ParseNode(Boolean isBlock, Boolean isIndentlessSequence)
   at YamlDotNet.Core.Parser.ParseFlowSequenceEntry(Boolean isFirst)
   at YamlDotNet.Core.Parser.StateMachine()
   at YamlDotNet.Core.Parser.MoveNext()
   at YamlDotNet.RepresentationModel.LibYamlEventStream.WriteTo(TextWriter textWriter)
   at Program.Main(String[] commandLineArguments)
Aborted (core dumped)
+STR
+DOC ---
+SEQ
=VAL :a
=VAL :b
=VAL :c

dotnet-yamldotnet-json

 invalid_correct
Unhandled exception. YamlDotNet.Core.SemanticErrorException: (Line: 2, Col: 12, Idx: 15) - (Line: 2, Col: 13, Idx: 16): While parsing a node, did not find expected node content.
   at YamlDotNet.Core.Parser.ParseNode(Boolean isBlock, Boolean isIndentlessSequence)
   at YamlDotNet.Core.Parser.ParseFlowSequenceEntry(Boolean isFirst)
   at YamlDotNet.Core.Parser.StateMachine()
   at YamlDotNet.Core.Parser.MoveNext()
   at YamlDotNet.Core.ParserExtensions.TryConsume[T](IParser parser, T& event)
   at YamlDotNet.Serialization.NodeDeserializers.ScalarNodeDeserializer.YamlDotNet.Serialization.INodeDeserializer.Deserialize(IParser parser, Type expectedType, Func`3 nestedObjectDeserializer, Object& value)
   at YamlDotNet.Serialization.ValueDeserializers.NodeValueDeserializer.DeserializeValue(IParser parser, Type expectedType, SerializerState state, IValueDeserializer nestedObjectDeserializer)
   at YamlDotNet.Serialization.ValueDeserializers.AliasValueDeserializer.DeserializeValue(IParser parser, Type expectedType, SerializerState state, IValueDeserializer nestedObjectDeserializer)
   at YamlDotNet.Serialization.ValueDeserializers.NodeValueDeserializer.<>c__DisplayClass3_0.<DeserializeValue>b__0(IParser r, Type t)
   at YamlDotNet.Serialization.NodeDeserializers.CollectionNodeDeserializer.DeserializeHelper(Type tItem, IParser parser, Func`3 nestedObjectDeserializer, IList result, Boolean canUpdate)
   at YamlDotNet.Serialization.NodeDeserializers.CollectionNodeDeserializer.YamlDotNet.Serialization.INodeDeserializer.Deserialize(IParser parser, Type expectedType, Func`3 nestedObjectDeserializer, Object& value)
   at YamlDotNet.Serialization.ValueDeserializers.NodeValueDeserializer.DeserializeValue(IParser parser, Type expectedType, SerializerState state, IValueDeserializer nestedObjectDeserializer)
   at YamlDotNet.Serialization.ValueDeserializers.AliasValueDeserializer.DeserializeValue(IParser parser, Type expectedType, SerializerState state, IValueDeserializer nestedObjectDeserializer)
   at YamlDotNet.Serialization.Deserializer.Deserialize(IParser parser, Type type)
   at YamlDotNet.Serialization.Deserializer.Deserialize(TextReader input, Type type)
   at YamlDotNet.Serialization.Deserializer.Deserialize(TextReader input)
   at Program.Main(String[] commandLineArguments)
Aborted (core dumped)

go-yaml-json

 invalid_correct
yaml: line 1: did not find expected node content

hs-hsyaml-event

 invalid_correct
Parsing error near byte offset Pos {posByteOffset = 4, posCharOffset = 4, posLine = 2, posColumn = 0} (Lexical error near "[ a, b, c, , ]")
+STR
+DOC ---
=VAL :

hs-hsyaml-json

 invalid_correct
hsyaml-parser: user error (Lexical error near "[ a, b, c, , ]")

js-jsyaml-json

 invalid_correct
/node/node_modules/js-yaml/lib/loader.js:187
  throw generateError(state, message);
  ^
YAMLException: expected the node content, but found ',' (2:12)

 1 | ---
 2 | [ a, b, c, , ]
----------------^
    at generateError (/node/node_modules/js-yaml/lib/loader.js:183:10)
    at throwError (/node/node_modules/js-yaml/lib/loader.js:187:9)
    at readFlowCollection (/node/node_modules/js-yaml/lib/loader.js:761:7)
    at composeNode (/node/node_modules/js-yaml/lib/loader.js:1442:11)
    at readBlockMapping (/node/node_modules/js-yaml/lib/loader.js:1104:12)
    at composeNode (/node/node_modules/js-yaml/lib/loader.js:1441:12)
    at readDocument (/node/node_modules/js-yaml/lib/loader.js:1625:3)
    at loadDocuments (/node/node_modules/js-yaml/lib/loader.js:1688:5)
    at Object.loadAll (/node/node_modules/js-yaml/lib/loader.js:1701:19)
    at Object.<anonymous> (/yaml/bin/js-jsyaml-json:7:13) {
  reason: "expected the node content, but found ','",
  mark: {
    name: null,
    buffer: '---\n[ a, b, c, , ]\n',
    position: 15,
    line: 1,
    column: 11,
    snippet: ' 1 | ---\n 2 | [ a, b, c, , ]\n----------------^'
  }
}

Node.js v20.13.1

js-yaml-event

 invalid_correct
Unexpected , in flow sequence at line 2, column 12:

[ a, b, c, , ]
           ^
+STR
+DOC ---
+SEQ []
=VAL :a
=VAL :b
=VAL :c
-SEQ
-DOC
-STR

js-yaml-json

 invalid_correct
/yaml/bin/js-yaml-json:9
    if (doc.errors.length !== 0) throw doc.errors[0]
                                 ^

YAMLParseError: Unexpected , in flow sequence at line 2, column 12:

[ a, b, c, , ]
           ^

    at Composer.onError (/node/node_modules/yaml/dist/compose/composer.js:69:34)
    at Object.resolveProps (/node/node_modules/yaml/dist/compose/resolve-props.js:108:25)
    at Object.resolveFlowCollection (/node/node_modules/yaml/dist/compose/resolve-flow-collection.js:27:36)
    at resolveCollection (/node/node_modules/yaml/dist/compose/compose-collection.js:16:37)
    at Object.composeCollection (/node/node_modules/yaml/dist/compose/compose-collection.js:47:16)
    at Object.composeNode (/node/node_modules/yaml/dist/compose/compose-node.js:31:38)
    at Object.composeDoc (/node/node_modules/yaml/dist/compose/compose-doc.js:34:23)
    at Composer.next (/node/node_modules/yaml/dist/compose/composer.js:149:40)
    at next (<anonymous>)
    at Composer.compose (/node/node_modules/yaml/dist/compose/composer.js:131:25) {
  code: 'UNEXPECTED_TOKEN',
  pos: [ 15, 16 ],
  linePos: [ { line: 2, col: 12 }, { line: 2, col: 13 } ]
}

Node.js v20.13.1

lua-lyaml-json

 invalid_correct
luajit: 2:9: did not find expected node content
stack traceback:
	[C]: in function 'error'
	/usr/local/share/lua/5.1/lyaml/init.lua:306: in function 'error'
	/usr/local/share/lua/5.1/lyaml/init.lua:325: in function 'parse'
	/usr/local/share/lua/5.1/lyaml/init.lua:443: in function 'load_node'
	/usr/local/share/lua/5.1/lyaml/init.lua:393: in function 'load_node'
	/usr/local/share/lua/5.1/lyaml/init.lua:497: in function 'load'
	/yaml/bin/lua-lyaml-json:6: in main chunk
	[C]: at 0x558db1eabed0

perl-pp-event

 invalid_correct
Line      : 2
Column    : 12
Expected  : ALIAS COLON FLOWMAP_START FLOWSEQ_START PLAIN PLAIN_MULTI QUOTED QUOTED_MULTILINE
Got       : FLOW_COMMA
Where     : /perl5/lib/perl5/YAML/PP/Parser.pm line 392
YAML      : ", ]"
  at /yaml/bin/perl-pp-event line 46.
+STR
+DOC ---
+SEQ []
=VAL :a
=VAL :b
=VAL :c

perl-pp-json

 invalid_correct
Line      : 2
Column    : 12
Expected  : ALIAS COLON FLOWMAP_START FLOWSEQ_START PLAIN PLAIN_MULTI QUOTED QUOTED_MULTILINE
Got       : FLOW_COMMA
Where     : /perl5/lib/perl5/YAML/PP/Parser.pm line 392
YAML      : ", ]"
  at /perl5/lib/perl5/YAML/PP/Loader.pm line 94.

perl-pp-perl

 invalid_correct
Line      : 2
Column    : 12
Expected  : ALIAS COLON FLOWMAP_START FLOWSEQ_START PLAIN PLAIN_MULTI QUOTED QUOTED_MULTILINE
Got       : FLOW_COMMA
Where     : /perl5/lib/perl5/YAML/PP/Parser.pm line 392
YAML      : ", ]"
  at /perl5/lib/perl5/YAML/PP/Loader.pm line 94.

perl-pplibyaml-json

 invalid_correct
YAML::PP::LibYAML Error: The problem:

    did not find expected node content

was found at , line: 2, column: 12
while parsing a flow node at line: 2, column: 12

perl-pplibyaml-perl

 invalid_correct
YAML::PP::LibYAML Error: The problem:

    did not find expected node content

was found at , line: 2, column: 12
while parsing a flow node at line: 2, column: 12

perl-refparser-event

 invalid_correct
Parser finished before end of input at /perl5/lib/perl5/YAML/Parser.pm line 4056, <> line 1.

perl-syck-json

 invalid_correct
Syck parser (line 2, column 12): syntax error at /perl5/lib/perl5/x86_64-linux-thread-multi/YAML/Syck.pm line 60, <> line 1.

perl-syck-perl

 invalid_correct
Syck parser (line 2, column 12): syntax error at /perl5/lib/perl5/x86_64-linux-thread-multi/YAML/Syck.pm line 60, <> line 1.

perl-tiny-json

 invalid_correct
YAML::Tiny failed to classify line '[ a, b, c, , ]' at /yaml/bin/perl-tiny-json line 12.

perl-tiny-perl

 invalid_correct
YAML::Tiny failed to classify line '[ a, b, c, , ]' at /yaml/bin/perl-tiny-perl line 15.

perl-xs-json

 invalid_correct
YAML::XS::Load Error: The problem:

    did not find expected node content

was found at document: 1, line: 2, column: 12
while parsing a flow node at line: 2, column: 12

perl-xs-perl

 invalid_correct
YAML::XS::Load Error: The problem:

    did not find expected node content

was found at document: 1, line: 2, column: 12
while parsing a flow node at line: 2, column: 12

perl-yaml-json

 invalid_correct
YAML Error: Expected separator '---'
   Code: YAML_PARSE_ERR_NO_SEPARATOR
   Line: 2
   Document: 2
 at /perl5/lib/perl5/YAML/Loader.pm line 88.

perl-yaml-perl

 invalid_correct
YAML Error: Expected separator '---'
   Code: YAML_PARSE_ERR_NO_SEPARATOR
   Line: 2
   Document: 2
 at /perl5/lib/perl5/YAML/Loader.pm line 88.

py-pyyaml-event

 invalid_correct
Traceback (most recent call last):
  File "/yaml/bin/py-pyyaml-event", line 7, in <module>
    for event in yaml.parse(sys.stdin.read()):
  File "/python/lib/python3.12/site-packages/yaml/__init__.py", line 75, in parse
    while loader.check_event():
          ^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 98, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 495, in parse_flow_sequence_entry
    return self.parse_flow_node()
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 268, in parse_flow_node
    return self.parse_node()
           ^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 369, in parse_node
    raise ParserError("while parsing a %s node" % node, start_mark,
yaml.parser.ParserError: while parsing a flow node
expected the node content, but found ','
  in "<unicode string>", line 2, column 12:
    [ a, b, c, , ]
               ^
+STR
+DOC ---
+SEQ []
=VAL :a
=VAL :b
=VAL :c

py-pyyaml-json

 invalid_correct
Traceback (most recent call last):
  File "/yaml/bin/py-pyyaml-json", line 19, in <module>
    for doc in yaml.load_all(sys.stdin.read(), Loader=yaml.FullLoader):
  File "/python/lib/python3.12/site-packages/yaml/__init__.py", line 130, in load_all
    yield loader.get_data()
          ^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/constructor.py", line 45, in get_data
    return self.construct_document(self.get_node())
                                   ^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 27, in get_node
    return self.compose_document()
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 55, in compose_document
    node = self.compose_node(None, None)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 82, in compose_node
    node = self.compose_sequence_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 110, in compose_sequence_node
    while not self.check_event(SequenceEndEvent):
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 98, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 495, in parse_flow_sequence_entry
    return self.parse_flow_node()
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 268, in parse_flow_node
    return self.parse_node()
           ^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 369, in parse_node
    raise ParserError("while parsing a %s node" % node, start_mark,
yaml.parser.ParserError: while parsing a flow node
expected the node content, but found ','
  in "<unicode string>", line 2, column 12:
    [ a, b, c, , ]
               ^

py-pyyaml-py

 invalid_correct
Traceback (most recent call last):
  File "/yaml/bin/py-pyyaml-py", line 36, in <module>
    for doc in yaml.load_all(sys.stdin.read(), Loader=yaml.FullLoader):
  File "/python/lib/python3.12/site-packages/yaml/__init__.py", line 130, in load_all
    yield loader.get_data()
          ^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/constructor.py", line 45, in get_data
    return self.construct_document(self.get_node())
                                   ^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 27, in get_node
    return self.compose_document()
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 55, in compose_document
    node = self.compose_node(None, None)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 82, in compose_node
    node = self.compose_sequence_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 110, in compose_sequence_node
    while not self.check_event(SequenceEndEvent):
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 98, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 495, in parse_flow_sequence_entry
    return self.parse_flow_node()
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 268, in parse_flow_node
    return self.parse_node()
           ^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 369, in parse_node
    raise ParserError("while parsing a %s node" % node, start_mark,
yaml.parser.ParserError: while parsing a flow node
expected the node content, but found ','
  in "<unicode string>", line 2, column 12:
    [ a, b, c, , ]
               ^

py-ruamel-event

 invalid_correct
Traceback (most recent call last):
  File "/yaml/bin/py-ruamel-event", line 9, in <module>
    for event in yaml.parse(sys.stdin.read()):
  File "/python/lib/python3.12/site-packages/ruamel/yaml/main.py", line 371, in parse
    while parser.check_event():
          ^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 141, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 694, in parse_flow_sequence_entry
    return self.parse_flow_node()
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 352, in parse_flow_node
    return self.parse_node()
           ^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 516, in parse_node
    raise ParserError(
ruamel.yaml.parser.ParserError: while parsing a flow node
expected the node content, but found ','
  in "<unicode string>", line 2, column 12:
    [ a, b, c, , ]
               ^ (line: 2)
+STR
+DOC ---
+SEQ []
=VAL :a
=VAL :b
=VAL :c

py-ruamel-json

 invalid_correct
Traceback (most recent call last):
  File "/yaml/bin/py-ruamel-json", line 21, in <module>
    for doc in yaml.load_all(sys.stdin.read()):
  File "/python/lib/python3.12/site-packages/ruamel/yaml/main.py", line 476, in load_all
    yield constructor.get_data()
          ^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/constructor.py", line 110, in get_data
    return self.construct_document(self.composer.get_node())
                                   ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 63, in get_node
    return self.compose_document()
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 94, in compose_document
    node = self.compose_node(None, None)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 128, in compose_node
    node = self.compose_sequence_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 172, in compose_sequence_node
    while not self.parser.check_event(SequenceEndEvent):
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 141, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 694, in parse_flow_sequence_entry
    return self.parse_flow_node()
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 352, in parse_flow_node
    return self.parse_node()
           ^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 516, in parse_node
    raise ParserError(
ruamel.yaml.parser.ParserError: while parsing a flow node
expected the node content, but found ','
  in "<unicode string>", line 2, column 12:
    [ a, b, c, , ]
               ^ (line: 2)

py-ruamel-py

 invalid_correct
Traceback (most recent call last):
  File "/yaml/bin/py-ruamel-py", line 38, in <module>
    for doc in yaml.load_all(sys.stdin.read()):
  File "/python/lib/python3.12/site-packages/ruamel/yaml/main.py", line 476, in load_all
    yield constructor.get_data()
          ^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/constructor.py", line 110, in get_data
    return self.construct_document(self.composer.get_node())
                                   ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 63, in get_node
    return self.compose_document()
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 94, in compose_document
    node = self.compose_node(None, None)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 128, in compose_node
    node = self.compose_sequence_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/composer.py", line 172, in compose_sequence_node
    while not self.parser.check_event(SequenceEndEvent):
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 141, in check_event
    self.current_event = self.state()
                         ^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 694, in parse_flow_sequence_entry
    return self.parse_flow_node()
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 352, in parse_flow_node
    return self.parse_node()
           ^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/parser.py", line 516, in parse_node
    raise ParserError(
ruamel.yaml.parser.ParserError: while parsing a flow node
expected the node content, but found ','
  in "<unicode string>", line 2, column 12:
    [ a, b, c, , ]
               ^ (line: 2)

ruby-psych-json

 invalid_correct
/ruby/gems/psych/lib/psych.rb:458:in `parse': (<unknown>): did not find expected node content while parsing a flow node at line 2 column 12 (Psych::SyntaxError)
	from /ruby/gems/psych/lib/psych.rb:458:in `parse_stream'
	from /ruby/gems/psych/lib/psych.rb:632:in `load_stream'
	from /yaml/bin/ruby-psych-json:6:in `<main>'

rust-yamlrust-event

 invalid_correct
Error: ScanError { mark: Marker { index: 15, line: 2, col: 11 }, info: "while parsing a node, did not find expected node content" }
+STR
+DOC
+SEQ
=VAL :a
=VAL :b
=VAL :c