iOfficeAI/OfficeCLI · error · ArgumentException

diagram type '{kind}' is not supported yet (currently: flowc

Error message

diagram type '{kind}' is not supported yet (currently: flowchart, sequenceDiagram).

What it means

Thrown by DiagramCompiler.Compile (DiagramCompiler.cs:33) when the first meaningful line of the mermaid source starts with a letter (so it is not treated as a bare/empty flowchart default) but does not match flowchart/graph or sequenceDiagram headers. Only flowchart and sequenceDiagram have native layout engines; the 'diagram' umbrella name rejects unsupported types with a clear message rather than producing garbage.

Source

Thrown at src/officecli/Core/Diagram/DiagramCompiler.cs:33

/// </summary>
public static class DiagramCompiler
{
    public static LaidOutGraph Compile(string mermaid)
    {
        var header = FirstMeaningfulLine(mermaid);

        if (Regex.IsMatch(header, @"^(flowchart|graph)\b", RegexOptions.IgnoreCase))
            return FlowchartLayout.Layout(MermaidParser.Parse(mermaid));

        if (Regex.IsMatch(header, @"^sequenceDiagram\b", RegexOptions.IgnoreCase))
            return SequenceLayout.Layout(SequenceLayout.Parse(mermaid));

        // No explicit header → assume flowchart (mermaid's own lenient default).
        if (header.Length == 0 || !Regex.IsMatch(header, @"^[A-Za-z]"))
            return FlowchartLayout.Layout(MermaidParser.Parse(mermaid));

        var kind = Regex.Match(header, @"^[A-Za-z]+").Value;
        throw new ArgumentException(
            $"diagram type '{kind}' is not supported yet (currently: flowchart, sequenceDiagram).");
    }

    private static string FirstMeaningfulLine(string text)
    {
        foreach (var raw in text.Split('\n'))
        {
            var s = raw.Trim();
            if (s.Length > 0 && !s.StartsWith("%%"))
                return s;
        }
        return "";
    }
}

View on GitHub (pinned to 1ced45e900)

Solutions

  1. Restrict the native synthesizer to flowchart or sequenceDiagram sources.
  2. For other mermaid types (class, state, gantt, pie, er, git, mindmap), use render=image so the real mermaid.js renders a PNG via mmdc or a chrome-family browser.
  3. Add an explicit 'flowchart TD' header if the source is meant to be a flowchart.

Example fix

// before
(mermaid source)
classDiagram
  Animal <|-- Dog
// after — use render=image for unsupported types, or switch to flowchart:
(mermaid source, render=image)
classDiagram
  Animal <|-- Dog
Defensive patterns

Strategy: validation

Validate before calling

static readonly Regex SupportedDiagramHeader = new(@"^(flowchart|graph|sequenceDiagram)\b", RegexOptions.IgnoreCase);
static string ValidateDiagramHeader(string mermaid)
{
    var first = mermaid.Split('\n').Select(l => l.Trim()).FirstOrDefault(l => l.Length > 0 && !l.StartsWith("%%")) ?? "";
    if (first.Length == 0 || !Regex.IsMatch(first, @"^[A-Za-z]")) return mermaid; // defaults to flowchart
    return SupportedDiagramHeader.IsMatch(first) ? mermaid : throw new ArgumentException($"unsupported diagram type: {Regex.Match(first, @"^[A-Za-z]+").Value}");
}

Type guard

static bool IsSupportedDiagramType(string mermaid)
{
    var first = mermaid.Split('\n').Select(l => l.Trim()).FirstOrDefault(l => l.Length > 0 && !l.StartsWith("%%")) ?? "";
    return first.Length == 0 || !Regex.IsMatch(first, @"^[A-Za-z]") || SupportedDiagramHeader.IsMatch(first);
}

Try / catch

try { DiagramCompiler.Compile(mermaid); }
catch (ArgumentException ex) when (ex.Message.Contains("is not supported yet"))
{ /* switch to render=image for the unsupported type, or use flowchart/sequenceDiagram */ }

Prevention

When it happens

Trigger: Compiling a mermaid source whose header is 'classDiagram', 'stateDiagram', 'gantt', 'pie', 'erDiagram', 'gitGraph', 'mindmap', or any other unsupported mermaid type via the native synthesizer.

Common situations: Pasting a class/state/ER diagram expecting native shapes; the native synthesizer only covers flowchart and sequenceDiagram, so other types need render=image (mmdc/chrome) instead of the built-in layout.

Related errors

AI-assisted analysis of iOfficeAI/OfficeCLI@1ced45e900 (2026-08-13). Data as JSON: /api/errors/c493591758f1408a. Report an issue: GitHub.