Files
sukr/src/mermaid.rs
Timothy DeHerrera d417e1c535 feat(mermaid): integrate diagram rendering into markdown pipeline
Intercept 'mermaid' code blocks in render.rs and call
mermaid::render_diagram() to convert to inline SVG.

- Use catch_unwind to handle upstream dagre_rust panics gracefully
- Graceful fallback: show raw code with mermaid-error class on failure
- Flowcharts render correctly; some diagram types hit upstream bugs
2026-01-28 20:36:45 -07:00

64 lines
1.8 KiB
Rust

//! Mermaid diagram rendering via mermaid-rs-renderer.
//!
//! Converts Mermaid diagram definitions to SVG at build-time.
use mermaid_rs_renderer::RenderOptions;
use std::panic;
/// Render a Mermaid diagram to SVG.
///
/// # Arguments
/// * `code` - The Mermaid diagram definition
///
/// # Returns
/// The rendered SVG string, or an error message on failure.
///
/// # Note
/// Uses catch_unwind to handle panics in upstream dependencies gracefully.
pub fn render_diagram(code: &str) -> Result<String, String> {
let code = code.to_owned();
let result = panic::catch_unwind(move || {
let opts = RenderOptions::modern();
mermaid_rs_renderer::render_with_options(&code, opts)
});
match result {
Ok(Ok(svg)) => Ok(svg),
Ok(Err(e)) => Err(e.to_string()),
Err(_) => Err("mermaid rendering panicked (upstream bug)".to_string()),
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_simple_flowchart() {
let result = render_diagram("flowchart LR; A-->B-->C").unwrap();
assert!(result.contains("<svg"));
assert!(result.contains("</svg>"));
}
#[test]
fn test_sequence_diagram() {
let result = render_diagram("sequenceDiagram\n Alice->>Bob: Hello").unwrap();
assert!(result.contains("<svg"));
}
#[test]
fn test_invalid_syntax_no_panic() {
// Should not panic, returns error
let result = render_diagram("invalid diagram syntax ???");
// May succeed with error node or fail gracefully
assert!(result.is_ok() || result.is_err());
}
#[test]
fn test_state_diagram() {
let result =
render_diagram("stateDiagram-v2\n [*] --> Idle\n Idle --> Processing: Start");
assert!(result.is_ok() || result.is_err());
}
}