# YAML Test Matrix

--- &test-M2N8:00
  Title: Question mark edge cases
  Tags: [ edge, empty-key ]

YAML

- ? : x

Expected Events

+STR
+DOC
+SEQ
+MAP
+MAP
=VAL :
=VAL :x
-MAP
=VAL :
-MAP
-SEQ
-DOC
-STR

Expected JSON



c-libfyaml-event

 ok

cpp-yamlcpp-event

 ok

hs-hsyaml-event

 ok

js-yaml-event

 ok

nim-nimyaml-event

 ok

perl-pp-event

 ok

perl-refparser-event

 ok

py-ruamel-event

 ok

rust-yamlrust-event

 ok

cpp-rapidyaml-event

 diff
Minimal Events:
+STR
+DOC
+SEQ
+MAP
+MAP
=VAL :
=VAL :x
-MAP
=VAL :
-MAP
-SEQ
-DOC
-STR
Transformed Events:
+STR
+DOC
+SEQ
+MAP
=VAL :
=VAL :x
-MAP
-SEQ
-DOC
-STR
Got Events:
+STR
+DOC
+SEQ
+MAP
=VAL :
=VAL :x
-MAP
-SEQ
-DOC
-STR

dotnet-yamldotnet-event

 diff
Minimal Events:
+STR
+DOC
+SEQ
+MAP
+MAP
=VAL :
=VAL :x
-MAP
=VAL :
-MAP
-SEQ
-DOC
-STR
Got Events:
+STR
+DOC
+SEQ
+MAP
+MAP
=VAL :
-MAP
=VAL :
-MAP
-SEQ
-DOC
-STR

perl-syck-perl

 error
Syck parser (line 1, column 5): syntax error at /perl5/lib/perl5/x86_64-linux-thread-multi/YAML/Syck.pm line 60, <> line 1.

py-ruamel-py

 error
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/constructor.py", line 125, in construct_document
    for _dummy in generator:
  File "/python/lib/python3.12/site-packages/ruamel/yaml/constructor.py", line 633, in construct_yaml_map
    value = self.construct_mapping(node)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/constructor.py", line 429, in construct_mapping
    return BaseConstructor.construct_mapping(self, node, deep=deep)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/constructor.py", line 237, in construct_mapping
    raise ConstructorError(
ruamel.yaml.constructor.ConstructorError: while constructing a mapping
  in "<unicode string>", line 1, column 3:
    - ? : x
      ^ (line: 1)
found unhashable key
  in "<unicode string>", line 1, column 5:
    - ? : x
        ^ (line: 1)

c-libfyaml-json

 na
[
  {
]

dotnet-yamldotnet-json

 na
Unhandled exception. YamlDotNet.Core.YamlException: (Line: 1, Col: 1, Idx: 0) - (Line: 1, Col: 1, Idx: 0): No node deserializer was able to deserialize the node into type System.Object, System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e
   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.DictionaryNodeDeserializer.DeserializeHelper(Type tKey, Type tValue, IParser parser, Func`3 nestedObjectDeserializer, IDictionary result)
   at YamlDotNet.Serialization.NodeDeserializers.DictionaryNodeDeserializer.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.DictionaryNodeDeserializer.DeserializeHelper(Type tKey, Type tValue, IParser parser, Func`3 nestedObjectDeserializer, IDictionary result)
   at YamlDotNet.Serialization.NodeDeserializers.DictionaryNodeDeserializer.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

 na
yaml: did not find expected key

hs-hsyaml-json

 na
[{"{\"\":\"x\"}":null}]

hs-reference-yeast

 na
Line  Col Char Byte Token|Content
   1    0    0    0 +DOC |
   1    0    0    0 +NODE|
   1    0    0    0 +SEQ |
   1    0    0    0 =SYNX|-
   1    1    1    1 =DENT|.
   1    2    2    2 +NODE|
   1    2    2    2 +MAP |
   1    2    2    2 +PAIR|
   1    2    2    2 =SYNX|?
   1    3    3    3 =DENT|.
   1    4    4    4 +NODE|
   1    4    4    4 +MAP |
   1    4    4    4 +PAIR|
   1    4    4    4 +NODE|
   1    4    4    4 +VAL |
   1    4    4    4 -VAL |
   1    4    4    4 -NODE|
   1    4    4    4 =SYNX|:
   1    5    5    5 =WSPC|.
   1    6    6    6 +NODE|
   1    6    6    6 +VAL |
   1    6    6    6 =TEXT|x
   1    7    7    7 -VAL |
   1    7    7    7 -NODE|
   1    7    7    7 =EOL |\x0a
   2    0    8    8 -PAIR|
   2    0    8    8 -MAP |
   2    0    8    8 -NODE|
   2    0    8    8 +NODE|
   2    0    8    8 +VAL |
   2    0    8    8 -VAL |
   2    0    8    8 -NODE|
   2    0    8    8 -PAIR|
   2    0    8    8 -MAP |
   2    0    8    8 -NODE|
   2    0    8    8 -SEQ |
   2    0    8    8 -NODE|
   2    0    8    8 -DOC |

js-jsyaml-json

 na
/node/node_modules/js-yaml/lib/loader.js:187
  throw generateError(state, message);
  ^
YAMLException: incomplete explicit mapping pair; a key node is missed; or followed by a non-tabulated empty line (1:5)

 1 | - ? : x
---------^
    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 readBlockMapping (/node/node_modules/js-yaml/lib/loader.js:1090:9)
    at composeNode (/node/node_modules/js-yaml/lib/loader.js:1441:12)
    at readBlockMapping (/node/node_modules/js-yaml/lib/loader.js:1164:11)
    at composeNode (/node/node_modules/js-yaml/lib/loader.js:1441:12)
    at readBlockSequence (/node/node_modules/js-yaml/lib/loader.js:1008:5)
    at composeNode (/node/node_modules/js-yaml/lib/loader.js:1440:12)
    at readDocument (/node/node_modules/js-yaml/lib/loader.js:1625:3)
    at loadDocuments (/node/node_modules/js-yaml/lib/loader.js:1688:5) {
  reason: 'incomplete explicit mapping pair; a key node is missed; or followed by a non-tabulated empty line',
  mark: {
    name: null,
    buffer: '- ? : x\n',
    position: 4,
    line: 0,
    column: 4,
    snippet: ' 1 | - ? : x\n---------^'
  }
}

Node.js v20.13.1

js-yaml-json

 na
[
  {
    "{ : x }": null
  }
]
(node:2934) Warning: Keys with collection values will be stringified due to JS Object restrictions: "{ : x }". Set mapAsMap: true to use object keys.
(Use `node --trace-warnings ...` to show where the warning was created)

lua-lyaml-json

 na
luajit: 1:5: did not find expected key
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:340: in function 'load_node'
	/usr/local/share/lua/5.1/lyaml/init.lua:340: 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 0x55757f452ed0

perl-pp-json

 na
[
   {
      "{'' => 'x'}" : null
   }
]

perl-pp-perl

 na
[
  {
    '{\'\' => \'x\'}' => undef
  }
]

perl-pplibyaml-json

 na
YAML::PP::LibYAML Error: The problem:

    did not find expected key

was found at , line: 1, column: 5
while parsing a block mapping at line: 1, column: 5

perl-syck-json

 na
Syck parser (line 1, column 5): syntax error at /perl5/lib/perl5/x86_64-linux-thread-multi/YAML/Syck.pm line 60, <> line 1.

perl-tiny-json

 na
[
   {
      "?" : "x"
   }
]

perl-tiny-perl

 na
[
  {
    '?' => 'x'
  }
]

perl-xs-json

 na
YAML::XS::Load Error: The problem:

    did not find expected key

was found at document: 1, line: 1, column: 5
while parsing a block mapping at line: 1, column: 5

perl-yaml-json

 na
[
   {
      ": x" : "x"
   }
]

perl-yaml-perl

 na
[
  {
    ': x' => 'x'
  }
]

py-pyyaml-json

 na
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 111, in compose_sequence_node
    node.value.append(self.compose_node(node, index))
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 84, in compose_node
    node = self.compose_mapping_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 129, in compose_mapping_node
    item_key = self.compose_node(node, None)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 84, in compose_node
    node = self.compose_mapping_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 127, in compose_mapping_node
    while not self.check_event(MappingEndEvent):
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  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 425, in parse_block_mapping_first_key
    return self.parse_block_mapping_key()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 438, in parse_block_mapping_key
    raise ParserError("while parsing a block mapping", self.marks[-1],
yaml.parser.ParserError: while parsing a block mapping
expected <block end>, but found ':'
  in "<unicode string>", line 1, column 5:
    - ? : x
        ^

py-ruamel-json

 na
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/constructor.py", line 125, in construct_document
    for _dummy in generator:
  File "/python/lib/python3.12/site-packages/ruamel/yaml/constructor.py", line 633, in construct_yaml_map
    value = self.construct_mapping(node)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/constructor.py", line 429, in construct_mapping
    return BaseConstructor.construct_mapping(self, node, deep=deep)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/ruamel/yaml/constructor.py", line 237, in construct_mapping
    raise ConstructorError(
ruamel.yaml.constructor.ConstructorError: while constructing a mapping
  in "<unicode string>", line 1, column 3:
    - ? : x
      ^ (line: 1)
found unhashable key
  in "<unicode string>", line 1, column 5:
    - ? : x
        ^ (line: 1)

ruby-psych-json

 na
/ruby/gems/psych/lib/psych.rb:458:in `parse': (<unknown>): did not find expected key while parsing a block mapping at line 1 column 5 (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>'

c-libyaml-event

 ni
+STR
+DOC
+SEQ
+MAP
+MAP
Parse error: did not find expected key

perl-pplibyaml-perl

 ni
YAML::PP::LibYAML Error: The problem:

    did not find expected key

was found at , line: 1, column: 5
while parsing a block mapping at line: 1, column: 5

perl-xs-perl

 ni
YAML::XS::Load Error: The problem:

    did not find expected key

was found at document: 1, line: 1, column: 5
while parsing a block mapping at line: 1, column: 5

py-pyyaml-event

 ni
+STR
+DOC
+SEQ
+MAP
+MAP
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 425, in parse_block_mapping_first_key
    return self.parse_block_mapping_key()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 438, in parse_block_mapping_key
    raise ParserError("while parsing a block mapping", self.marks[-1],
yaml.parser.ParserError: while parsing a block mapping
expected <block end>, but found ':'
  in "<unicode string>", line 1, column 5:
    - ? : x
        ^

py-pyyaml-py

 ni
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 111, in compose_sequence_node
    node.value.append(self.compose_node(node, index))
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 84, in compose_node
    node = self.compose_mapping_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 129, in compose_mapping_node
    item_key = self.compose_node(node, None)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 84, in compose_node
    node = self.compose_mapping_node(anchor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/composer.py", line 127, in compose_mapping_node
    while not self.check_event(MappingEndEvent):
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  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 425, in parse_block_mapping_first_key
    return self.parse_block_mapping_key()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/python/lib/python3.12/site-packages/yaml/parser.py", line 438, in parse_block_mapping_key
    raise ParserError("while parsing a block mapping", self.marks[-1],
yaml.parser.ParserError: while parsing a block mapping
expected <block end>, but found ':'
  in "<unicode string>", line 1, column 5:
    - ? : x
        ^