iced-rs/iced · error

table row

Error message

table row

What it means

The markdown parser asserts that a table row exists when appending a cell to it via rows.last_mut().expect("table row"). Rows are pushed when a table's separator/header line is parsed, so this panic means a cell line was processed without a preceding valid table header/separator - an internal parser invariant violation.

Source

Thrown at widget/src/markdown.rs:937

                let Scope::Table {
                    alignment,
                    columns,
                    rows,
                    current,
                } = stack.last_mut()?
                else {
                    return None;
                };

                if columns.len() < alignment.len() {
                    columns.push(Column {
                        header: std::mem::take(current),
                        alignment: alignment[columns.len()],
                    });
                } else {
                    rows.last_mut()
                        .expect("table row")
                        .cells
                        .push(std::mem::take(current));
                }

                None
            }
            _ => None,
        },
        pulldown_cmark::Event::Text(text) if !metadata => {
            if code_block {
                code.push_str(&text);

                #[cfg(feature = "highlighter")]
                if let Some(highlighter) = &mut code_parser {
                    for line in text.lines() {
                        code_lines.push(Text::new(highlighter.parse_line(line).to_vec()));
                    }
                }

View on GitHub (pinned to d146509d89)

Solutions

1. Validate/sanitize the markdown before rendering: every table body must be preceded by a header row and a |---| delimiter row.
2. Inspect the input around the failing table and fix its syntax (missing or malformed delimiter line is the usual cause).
3. If content is untrusted, escape or pre-parse tables defensively, or pin the iced/iced_widgets version where your input is known to parse.
4. Report/upgrade: if the input is valid CommonMark, this is a parser bug - check for fixes in newer iced_widget releases.

Example fix

// before (input)
| a | b |
| c | d |
// after (input - add delimiter row)
| a | b |
|---|---|
| c | d |

// check tables are well-formed before handing markdown to the widget
fn table_has_delimiter(md: &str) -> bool {
    // every line starting with '|' body must be preceded by a |---| row
    let mut prev_sep = false;
    for line in md.lines() {
        let is_pipe = line.trim_start().starts_with('|');
        let is_sep = is_pipe && line.chars().all(|c| c == '|' || c == '-' || c == ':' || c.is_whitespace());
        if is_pipe && !is_sep && !prev_sep { return false; }
        prev_sep = is_sep;
    }
    true
}

When it happens

Trigger: Feeding markdown where a table body line (|a|b|) appears without a matching header+delimiter row, or malformed delimiter rows (e.g. |---|---| with wrong column alignment array length) such that the parser reaches the cell branch with rows empty.

Common situations: User-supplied markdown content with a near-miss table syntax (missing separator line, leading blank line removal quirks), or content truncated mid-table; can also surface when a previous alignment array indexed columns.len() out of range earlier in the same block.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• Line must be parsed
• Caches must not be empty
• Downcast widget state
• Downcast on stateless state
• {error:?}

AI-assisted analysis of iced-rs/iced@d146509d89 (2026-09-11). Data as JSON: /api/errors/9b0fe0cfe97b8763. Report an issue: GitHub.