{
  "generatedAt": "see git history",
  "environment": {
    "node": "v26.3.1",
    "python": "3.14.6",
    "machine": "Apple M5 Pro / macOS (Darwin 25.5.0)"
  },
  "cases": [
    {
      "id": "tab-indent",
      "mistake": "Indenting with a tab character instead of spaces",
      "yaml": "parent:\n\tchild: 1",
      "parsers": {
        "js-yaml 4.1.1 load (DEFAULT_SCHEMA)": {
          "outcome": "error",
          "errorName": "YAMLException",
          "message": "tab characters must not be used in indentation (2:1)\n\n 1 | parent:\n 2 | →child: 1\n-----^",
          "line": 2,
          "column": 1
        },
        "yaml (eemeli) 2.8.3 parse (defaults)": {
          "outcome": "error",
          "errorName": "YAMLParseError",
          "message": "Tabs are not allowed as indentation at line 2, column 1:\n\nparent:\n\tchild: 1\n^\n",
          "line": 2,
          "column": 1
        },
        "PyYAML 6.0.3 safe_load": {
          "outcome": "error",
          "errorName": "ScannerError",
          "message": "while scanning for the next token found character '\\t' that cannot start any token in \"<unicode string>\", line 2, column 1: child: 1 ^",
          "line": 2,
          "column": 1
        },
        "ruamel.yaml 0.19.1 YAML(typ='safe')": {
          "outcome": "error",
          "errorName": "ScannerError",
          "message": "while scanning for the next token found character '\\t' that cannot start any token in \"<file>\", line 2, column 1",
          "line": 2,
          "column": 1
        }
      }
    },
    {
      "id": "bad-indent",
      "mistake": "Sibling keys at inconsistent indentation (2 vs 3 spaces)",
      "yaml": "parent:\n  a: 1\n   b: 2",
      "parsers": {
        "js-yaml 4.1.1 load (DEFAULT_SCHEMA)": {
          "outcome": "error",
          "errorName": "YAMLException",
          "message": "bad indentation of a mapping entry (3:5)\n\n 1 | parent:\n 2 |   a: 1\n 3 |    b: 2\n---------^",
          "line": 3,
          "column": 5
        },
        "yaml (eemeli) 2.8.3 parse (defaults)": {
          "outcome": "error",
          "errorName": "YAMLParseError",
          "message": "Nested mappings are not allowed in compact mappings at line 2, column 6:\n\n  a: 1\n     ^\n",
          "line": 2,
          "column": 6
        },
        "PyYAML 6.0.3 safe_load": {
          "outcome": "error",
          "errorName": "ScannerError",
          "message": "mapping values are not allowed here in \"<unicode string>\", line 3, column 5: b: 2 ^",
          "line": 3,
          "column": 5
        },
        "ruamel.yaml 0.19.1 YAML(typ='safe')": {
          "outcome": "error",
          "errorName": "ScannerError",
          "message": "mapping values are not allowed here in \"<file>\", line 3, column 5",
          "line": 3,
          "column": 5
        }
      }
    },
    {
      "id": "colon-in-value",
      "mistake": "Unquoted value containing ': ' (colon + space) — parsed as a second mapping",
      "yaml": "url: http://example.com: 8080",
      "parsers": {
        "js-yaml 4.1.1 load (DEFAULT_SCHEMA)": {
          "outcome": "error",
          "errorName": "YAMLException",
          "message": "bad indentation of a mapping entry (1:24)\n\n 1 | url: http://example.com: 8080\n----------------------------^",
          "line": 1,
          "column": 24
        },
        "yaml (eemeli) 2.8.3 parse (defaults)": {
          "outcome": "error",
          "errorName": "YAMLParseError",
          "message": "Nested mappings are not allowed in compact mappings at line 1, column 6:\n\nurl: http://example.com: 8080\n     ^\n",
          "line": 1,
          "column": 6
        },
        "PyYAML 6.0.3 safe_load": {
          "outcome": "error",
          "errorName": "ScannerError",
          "message": "mapping values are not allowed here in \"<unicode string>\", line 1, column 24: url: http://example.com: 8080 ^",
          "line": 1,
          "column": 24
        },
        "ruamel.yaml 0.19.1 YAML(typ='safe')": {
          "outcome": "error",
          "errorName": "ScannerError",
          "message": "mapping values are not allowed here in \"<file>\", line 1, column 24",
          "line": 1,
          "column": 24
        }
      }
    },
    {
      "id": "unclosed-quote",
      "mistake": "Double-quoted string without a closing quote",
      "yaml": "name: \"unclosed string\nnext: 1",
      "parsers": {
        "js-yaml 4.1.1 load (DEFAULT_SCHEMA)": {
          "outcome": "error",
          "errorName": "YAMLException",
          "message": "unexpected end of the stream within a double quoted scalar (3:1)\n\n 1 | name: \"unclosed string\n 2 | next: 1\n 3 | \n-----^",
          "line": 3,
          "column": 1
        },
        "yaml (eemeli) 2.8.3 parse (defaults)": {
          "outcome": "error",
          "errorName": "YAMLParseError",
          "message": "Missing closing \"quote at line 2, column 8:\n\nnext: 1\n       ^\n",
          "line": 2,
          "column": 8
        },
        "PyYAML 6.0.3 safe_load": {
          "outcome": "error",
          "errorName": "ScannerError",
          "message": "while scanning a quoted scalar in \"<unicode string>\", line 1, column 7: name: \"unclosed string ^ found unexpected end of stream in \"<unicode string>\", line 2, column 8: next: 1 ^",
          "line": 2,
          "column": 8
        },
        "ruamel.yaml 0.19.1 YAML(typ='safe')": {
          "outcome": "error",
          "errorName": "ScannerError",
          "message": "while scanning a quoted scalar in \"<file>\", line 1, column 7 found unexpected end of stream in \"<file>\", line 2, column 8",
          "line": 2,
          "column": 8
        }
      }
    },
    {
      "id": "undefined-alias",
      "mistake": "Alias (*missing) referencing an anchor that was never defined",
      "yaml": "service: *missing",
      "parsers": {
        "js-yaml 4.1.1 load (DEFAULT_SCHEMA)": {
          "outcome": "error",
          "errorName": "YAMLException",
          "message": "unidentified alias \"missing\" (1:18)\n\n 1 | service: *missing\n----------------------^",
          "line": 1,
          "column": 18
        },
        "yaml (eemeli) 2.8.3 parse (defaults)": {
          "outcome": "error",
          "errorName": "ReferenceError",
          "message": "Unresolved alias (the anchor must be set before the alias): missing",
          "line": null,
          "column": null
        },
        "PyYAML 6.0.3 safe_load": {
          "outcome": "error",
          "errorName": "ComposerError",
          "message": "found undefined alias 'missing' in \"<unicode string>\", line 1, column 10: service: *missing ^",
          "line": 1,
          "column": 10
        },
        "ruamel.yaml 0.19.1 YAML(typ='safe')": {
          "outcome": "error",
          "errorName": "ComposerError",
          "message": "found undefined alias 'missing' in \"<file>\", line 1, column 10",
          "line": 1,
          "column": 10
        }
      }
    },
    {
      "id": "unclosed-flow",
      "mistake": "Flow sequence [ ... ] opened but never closed",
      "yaml": "ports: [8080, 9090\nname: web",
      "parsers": {
        "js-yaml 4.1.1 load (DEFAULT_SCHEMA)": {
          "outcome": "error",
          "errorName": "YAMLException",
          "message": "missed comma between flow collection entries (2:1)\n\n 1 | ports: [8080, 9090\n 2 | name: web\n-----^",
          "line": 2,
          "column": 1
        },
        "yaml (eemeli) 2.8.3 parse (defaults)": {
          "outcome": "error",
          "errorName": "YAMLParseError",
          "message": "Flow sequence in block collection must be sufficiently indented and end with a ] at line 2, column 1:\n\nports: [8080, 9090\nname: web\n^\n",
          "line": 2,
          "column": 1
        },
        "PyYAML 6.0.3 safe_load": {
          "outcome": "error",
          "errorName": "ParserError",
          "message": "while parsing a flow sequence in \"<unicode string>\", line 1, column 8: ports: [8080, 9090 ^ expected ',' or ']', but got ':' in \"<unicode string>\", line 2, column 5: name: web ^",
          "line": 2,
          "column": 5
        },
        "ruamel.yaml 0.19.1 YAML(typ='safe')": {
          "outcome": "error",
          "errorName": "ParserError",
          "message": "while parsing a flow sequence in \"<file>\", line 1, column 8 expected ',' or ']', but got ':' in \"<file>\", line 2, column 5",
          "line": 2,
          "column": 5
        }
      }
    },
    {
      "id": "template-brace",
      "mistake": "Template syntax {{ }} at the start of a value (Helm/Ansible before rendering)",
      "yaml": "image: {{ .Values.image }}",
      "parsers": {
        "js-yaml 4.1.1 load (DEFAULT_SCHEMA)": {
          "outcome": "parsed",
          "type": "object",
          "repr": "{\"image\":{\"[object Object]\":null}}"
        },
        "yaml (eemeli) 2.8.3 parse (defaults)": {
          "outcome": "parsed",
          "type": "object",
          "repr": "{\"image\":{\"{ .Values.image }\":null}}"
        },
        "PyYAML 6.0.3 safe_load": {
          "outcome": "error",
          "errorName": "ConstructorError",
          "message": "while constructing a mapping in \"<unicode string>\", line 1, column 8: image: {{ .Values.image }} ^ found unhashable key in \"<unicode string>\", line 1, column 9: image: {{ .Values.image }} ^",
          "line": 1,
          "column": 9
        },
        "ruamel.yaml 0.19.1 YAML(typ='safe')": {
          "outcome": "error",
          "errorName": "ConstructorError",
          "message": "while constructing a mapping in \"<file>\", line 1, column 8 found unhashable key in \"<file>\", line 1, column 9",
          "line": 1,
          "column": 9
        }
      }
    }
  ]
}