{
  "description": "Markdown rendering contract (issue #531): message text -> platform-neutral semantic tree. Both parsers — web (vendored markdown-it walked by web/static/markdown.js) and native (apple/swift-markdown walked by MarkdownTree.swift) — must normalize every input to exactly this tree. Blocks: p{children} quote{children} ul{items} ol{start,items} codeblock{text,lang}. Inlines: text{text} br code{text} link{href,children} strong/em/strike{children}. Adjacent text runs always merge. These vectors are the spec: when the twins disagree, fix the implementations, never the vectors.",
  "vectors": [
    {
      "name": "plain_text",
      "input": "hello world",
      "plain": "hello world",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "hello world"
            }
          ]
        }
      ]
    },
    {
      "name": "empty_message",
      "input": "",
      "tree": [],
      "note": "no blocks at all — renderers must tolerate an empty tree"
    },
    {
      "name": "whitespace_only",
      "input": "   ",
      "tree": []
    },
    {
      "name": "bold",
      "input": "**b**",
      "plain": "b",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "strong",
              "children": [
                {
                  "t": "text",
                  "text": "b"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "italic_star",
      "input": "*i*",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "em",
              "children": [
                {
                  "t": "text",
                  "text": "i"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "italic_underscore",
      "input": "_i_",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "em",
              "children": [
                {
                  "t": "text",
                  "text": "i"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "bold_italic",
      "input": "***bi***",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "em",
              "children": [
                {
                  "t": "strong",
                  "children": [
                    {
                      "t": "text",
                      "text": "bi"
                    }
                  ]
                }
              ]
            }
          ]
        }
      ],
      "note": "CommonMark nests em > strong (the old grammar rendered strong > em — visually identical)"
    },
    {
      "name": "intraword_underscore_literal",
      "input": "snake_case_name",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "snake_case_name"
            }
          ]
        }
      ],
      "note": "CommonMark forbids intraword _ emphasis, matching the old grammar's word-boundary gate"
    },
    {
      "name": "intraword_star_formats",
      "input": "in*ner*",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "in"
            },
            {
              "t": "em",
              "children": [
                {
                  "t": "text",
                  "text": "ner"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "spaced_stars_literal",
      "input": "a * b * c",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "a * b * c"
            }
          ]
        }
      ],
      "note": "flanking rules: the old grammar wrongly italicised ' b ' here — deliberate fix"
    },
    {
      "name": "nested_marks",
      "input": "**b _i_**",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "strong",
              "children": [
                {
                  "t": "text",
                  "text": "b "
                },
                {
                  "t": "em",
                  "children": [
                    {
                      "t": "text",
                      "text": "i"
                    }
                  ]
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "inline_code",
      "input": "`co*de*`",
      "plain": "co*de*",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "code",
              "text": "co*de*"
            }
          ]
        }
      ],
      "note": "markers never format inside code"
    },
    {
      "name": "inline_code_backtick",
      "input": "``a`b``",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "code",
              "text": "a`b"
            }
          ]
        }
      ]
    },
    {
      "name": "multiple_code_spans_with_link_like_content",
      "input": "hello `example.com` and `other.com` OK?",
      "plain": "hello example.com and other.com OK?",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "hello "
            },
            {
              "t": "code",
              "text": "example.com"
            },
            {
              "t": "text",
              "text": " and "
            },
            {
              "t": "code",
              "text": "other.com"
            },
            {
              "t": "text",
              "text": " OK?"
            }
          ]
        }
      ],
      "note": "issue #818: two SEPARATE code spans, each ending at its own nearest closing backtick — not one span greedily spanning first-backtick to last-backtick. Neither domain-looking span autolinks; code content never re-parses."
    },
    {
      "name": "strike_single_tilde",
      "input": "~s~",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "strike",
              "children": [
                {
                  "t": "text",
                  "text": "s"
                }
              ]
            }
          ]
        }
      ],
      "note": "history: old messages use the original grammar's single ~"
    },
    {
      "name": "strike_double_tilde",
      "input": "~~s~~",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "strike",
              "children": [
                {
                  "t": "text",
                  "text": "s"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "strike_mismatched_literal",
      "input": "~~s~",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "~~s~"
            }
          ]
        }
      ],
      "note": "an opener only pairs with a closer of the same length"
    },
    {
      "name": "strike_triple_tilde_inline_literal",
      "input": "x ~~~s~~~ y",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "x ~~~s~~~ y"
            }
          ]
        }
      ],
      "note": "runs of 3+ tildes never strike (cmark-gfm)"
    },
    {
      "name": "tilde_fence_info_string",
      "input": "~~~s~~~",
      "tree": [
        {
          "t": "codeblock",
          "text": "",
          "lang": "s~~~"
        }
      ],
      "note": "at line start this is a spec-valid unterminated tilde fence with info string 's~~~' — both parsers agree"
    },
    {
      "name": "strike_inside_em",
      "input": "*a ~b~ c*",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "em",
              "children": [
                {
                  "t": "text",
                  "text": "a "
                },
                {
                  "t": "strike",
                  "children": [
                    {
                      "t": "text",
                      "text": "b"
                    }
                  ]
                },
                {
                  "t": "text",
                  "text": " c"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "bold_link_interplay",
      "input": "**github.com/apps/x**",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "strong",
              "children": [
                {
                  "t": "link",
                  "href": "https://github.com/apps/x",
                  "children": [
                    {
                      "t": "text",
                      "text": "github.com/apps/x"
                    }
                  ]
                }
              ]
            }
          ]
        }
      ],
      "note": "the motivating #531 bug: emphasis spanning a bare link"
    },
    {
      "name": "bare_https_url",
      "input": "see https://example.com/a?b=1 now",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "see "
            },
            {
              "t": "link",
              "href": "https://example.com/a?b=1",
              "children": [
                {
                  "t": "text",
                  "text": "https://example.com/a?b=1"
                }
              ]
            },
            {
              "t": "text",
              "text": " now"
            }
          ]
        }
      ]
    },
    {
      "name": "www_url",
      "input": "www.example.com",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "link",
              "href": "https://www.example.com",
              "children": [
                {
                  "t": "text",
                  "text": "www.example.com"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "bare_tld_allowlisted",
      "input": "try example.com",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "try "
            },
            {
              "t": "link",
              "href": "https://example.com",
              "children": [
                {
                  "t": "text",
                  "text": "example.com"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "filenames_stay_plain",
      "input": "main.js and node.go",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "main.js and node.go"
            }
          ]
        }
      ],
      "note": "BARE_TLDS excludes file extensions"
    },
    {
      "name": "email_not_linked",
      "input": "mail a@b.com",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "mail a@b.com"
            }
          ]
        }
      ]
    },
    {
      "name": "explicit_link",
      "input": "[docs](https://example.com/a)",
      "plain": "docs",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "link",
              "href": "https://example.com/a",
              "children": [
                {
                  "t": "text",
                  "text": "docs"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "explicit_link_formatted_label",
      "input": "[**b**](https://example.com)",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "link",
              "href": "https://example.com",
              "children": [
                {
                  "t": "strong",
                  "children": [
                    {
                      "t": "text",
                      "text": "b"
                    }
                  ]
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "no_autolink_inside_link_label",
      "input": "[see example.com](https://y.com)",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "link",
              "href": "https://y.com",
              "children": [
                {
                  "t": "text",
                  "text": "see example.com"
                }
              ]
            }
          ]
        }
      ],
      "note": "links never nest — bare URLs in a label stay text"
    },
    {
      "name": "angle_autolink",
      "input": "<https://example.com>",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "link",
              "href": "https://example.com",
              "children": [
                {
                  "t": "text",
                  "text": "https://example.com"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "javascript_link_literal",
      "input": "[x](javascript:alert(1))",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "[x](javascript:alert(1))"
            }
          ]
        }
      ],
      "note": "validateLink: http(s) only — rejected links never tokenize"
    },
    {
      "name": "relative_link_literal",
      "input": "[x](/rel)",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "[x](/rel)"
            }
          ]
        }
      ]
    },
    {
      "name": "mailto_link_literal",
      "input": "[x](mailto:a@b.c)",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "[x](mailto:a@b.c)"
            }
          ]
        }
      ]
    },
    {
      "name": "heading_stays_literal",
      "input": "# hi **b**",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "# hi "
            },
            {
              "t": "strong",
              "children": [
                {
                  "t": "text",
                  "text": "b"
                }
              ]
            }
          ]
        }
      ],
      "note": "heading rule never enabled; inline still formats"
    },
    {
      "name": "hr_stays_literal",
      "input": "---",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "---"
            }
          ]
        }
      ]
    },
    {
      "name": "setext_stays_literal",
      "input": "title\n===",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "title"
            },
            {
              "t": "br"
            },
            {
              "t": "text",
              "text": "==="
            }
          ]
        }
      ]
    },
    {
      "name": "table_stays_literal",
      "input": "| a | b |\n| - | - |",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "| a | b |"
            },
            {
              "t": "br"
            },
            {
              "t": "text",
              "text": "| - | - |"
            }
          ]
        }
      ]
    },
    {
      "name": "image_stays_literal",
      "input": "![alt](https://x.com/i.png)",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "![alt](https://x.com/i.png)"
            }
          ]
        }
      ],
      "note": "images reconstruct as literal source text on both twins"
    },
    {
      "name": "image_bad_scheme_literal",
      "input": "![a](/rel)",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "![a](/rel)"
            }
          ]
        }
      ]
    },
    {
      "name": "tasklist_stays_literal",
      "input": "- [x] task",
      "tree": [
        {
          "t": "ul",
          "items": [
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "[x] task"
                  }
                ]
              }
            ]
          ]
        }
      ],
      "note": "native re-synthesizes the checkbox prefix cmark-gfm force-parses"
    },
    {
      "name": "inline_html_literal",
      "input": "<b>hi</b> **b**",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "<b>hi</b> "
            },
            {
              "t": "strong",
              "children": [
                {
                  "t": "text",
                  "text": "b"
                }
              ]
            }
          ]
        }
      ],
      "note": "native merges adjacent text around InlineHTML to match"
    },
    {
      "name": "indented_code_stays_plain",
      "input": "    indented",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "indented"
            }
          ]
        }
      ],
      "note": "the 4-space rule is never enabled — it mangles pasted text"
    },
    {
      "name": "smart_typography_stays_literal",
      "input": "\"quotes\" -- dashes...",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "\"quotes\" -- dashes..."
            }
          ]
        }
      ],
      "note": "pins native's .disableSmartOpts (cmark curls quotes by default)"
    },
    {
      "name": "bullet_list",
      "input": "- a\n- b",
      "plain": "a b",
      "tree": [
        {
          "t": "ul",
          "items": [
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "a"
                  }
                ]
              }
            ],
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "b"
                  }
                ]
              }
            ]
          ]
        }
      ]
    },
    {
      "name": "nested_list",
      "input": "- a\n  - b",
      "tree": [
        {
          "t": "ul",
          "items": [
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "a"
                  }
                ]
              },
              {
                "t": "ul",
                "items": [
                  [
                    {
                      "t": "p",
                      "children": [
                        {
                          "t": "text",
                          "text": "b"
                        }
                      ]
                    }
                  ]
                ]
              }
            ]
          ]
        }
      ]
    },
    {
      "name": "ordered_list_start",
      "input": "3. a\n4. b",
      "tree": [
        {
          "t": "ol",
          "start": 3,
          "items": [
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "a"
                  }
                ]
              }
            ],
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "b"
                  }
                ]
              }
            ]
          ]
        }
      ]
    },
    {
      "name": "loose_list_normalizes_tight",
      "input": "- a\n\n- b",
      "tree": [
        {
          "t": "ul",
          "items": [
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "a"
                  }
                ]
              }
            ],
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "b"
                  }
                ]
              }
            ]
          ]
        }
      ],
      "note": "loose/tight is erased — the tree (and rendering) is always tight"
    },
    {
      "name": "empty_list_item",
      "input": "- \n- b",
      "tree": [
        {
          "t": "ul",
          "items": [
            [],
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "b"
                  }
                ]
              }
            ]
          ]
        }
      ]
    },
    {
      "name": "paren_ordered_marker",
      "input": "1) paren marker",
      "tree": [
        {
          "t": "ol",
          "start": 1,
          "items": [
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "paren marker"
                  }
                ]
              }
            ]
          ]
        }
      ]
    },
    {
      "name": "list_interrupts_paragraph",
      "input": "text\n- a\n- b",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "text"
            }
          ]
        },
        {
          "t": "ul",
          "items": [
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "a"
                  }
                ]
              }
            ],
            [
              {
                "t": "p",
                "children": [
                  {
                    "t": "text",
                    "text": "b"
                  }
                ]
              }
            ]
          ]
        }
      ]
    },
    {
      "name": "blockquote",
      "input": "> q **b**",
      "tree": [
        {
          "t": "quote",
          "children": [
            {
              "t": "p",
              "children": [
                {
                  "t": "text",
                  "text": "q "
                },
                {
                  "t": "strong",
                  "children": [
                    {
                      "t": "text",
                      "text": "b"
                    }
                  ]
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "blockquote_lazy_continuation",
      "input": "> a\nb",
      "tree": [
        {
          "t": "quote",
          "children": [
            {
              "t": "p",
              "children": [
                {
                  "t": "text",
                  "text": "a"
                },
                {
                  "t": "br"
                },
                {
                  "t": "text",
                  "text": "b"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "blockquote_multi_paragraph",
      "input": "> a\n>\n> b",
      "tree": [
        {
          "t": "quote",
          "children": [
            {
              "t": "p",
              "children": [
                {
                  "t": "text",
                  "text": "a"
                }
              ]
            },
            {
              "t": "p",
              "children": [
                {
                  "t": "text",
                  "text": "b"
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "nested_blockquote",
      "input": "> > deep",
      "tree": [
        {
          "t": "quote",
          "children": [
            {
              "t": "quote",
              "children": [
                {
                  "t": "p",
                  "children": [
                    {
                      "t": "text",
                      "text": "deep"
                    }
                  ]
                }
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "list_in_blockquote",
      "input": "> - a\n> - b",
      "tree": [
        {
          "t": "quote",
          "children": [
            {
              "t": "ul",
              "items": [
                [
                  {
                    "t": "p",
                    "children": [
                      {
                        "t": "text",
                        "text": "a"
                      }
                    ]
                  }
                ],
                [
                  {
                    "t": "p",
                    "children": [
                      {
                        "t": "text",
                        "text": "b"
                      }
                    ]
                  }
                ]
              ]
            }
          ]
        }
      ]
    },
    {
      "name": "fence_in_blockquote",
      "input": "> ```\n> code\n> ```",
      "tree": [
        {
          "t": "quote",
          "children": [
            {
              "t": "codeblock",
              "text": "code",
              "lang": ""
            }
          ]
        }
      ]
    },
    {
      "name": "fenced_code",
      "input": "```js\ncode **here**\n```",
      "plain": "code **here**",
      "tree": [
        {
          "t": "codeblock",
          "text": "code **here**",
          "lang": "js"
        }
      ],
      "note": "trailing newline stripped from the tree's text"
    },
    {
      "name": "unterminated_fence",
      "input": "```\nunterminated",
      "tree": [
        {
          "t": "codeblock",
          "text": "unterminated",
          "lang": ""
        }
      ]
    },
    {
      "name": "tilde_fence",
      "input": "~~~\ntilde fence\n~~~",
      "tree": [
        {
          "t": "codeblock",
          "text": "tilde fence",
          "lang": ""
        }
      ]
    },
    {
      "name": "soft_break",
      "input": "a\nb",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "a"
            },
            {
              "t": "br"
            },
            {
              "t": "text",
              "text": "b"
            }
          ]
        }
      ],
      "note": "every newline is a break in chat — soft and hard breaks both normalize to br"
    },
    {
      "name": "hard_break_two_spaces",
      "input": "line  \nhard",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "line"
            },
            {
              "t": "br"
            },
            {
              "t": "text",
              "text": "hard"
            }
          ]
        }
      ]
    },
    {
      "name": "hard_break_backslash",
      "input": "back\\\nslash",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "back"
            },
            {
              "t": "br"
            },
            {
              "t": "text",
              "text": "slash"
            }
          ]
        }
      ]
    },
    {
      "name": "paragraph_split",
      "input": "a\n\nb",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "a"
            }
          ]
        },
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "b"
            }
          ]
        }
      ]
    },
    {
      "name": "backslash_escape",
      "input": "\\*lit\\*",
      "plain": "*lit*",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "*lit*"
            }
          ]
        }
      ],
      "note": "old clients show the backslashes — the composer serializer escapes minimally for this reason"
    },
    {
      "name": "entity_decodes",
      "input": "&amp; &lt;",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "& <"
            }
          ]
        }
      ],
      "note": "cmark decodes entities unconditionally; web enables the rule to match"
    },
    {
      "name": "mention_is_render_layer",
      "input": "@Ada hello",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "@Ada hello"
            }
          ]
        }
      ],
      "note": "mention chips are scanned at render time against the roster, never in the tree"
    },
    {
      "name": "emoji_is_render_layer",
      "input": "🎉",
      "tree": [
        {
          "t": "p",
          "children": [
            {
              "t": "text",
              "text": "🎉"
            }
          ]
        }
      ],
      "note": "jumbo-emoji detection stays a raw-text helper"
    }
  ]
}