fix: handle default 'cose-bilkent' layout in mindmap layer

on-behalf-of: @Mermaid-Chart <hello@mermaidchart.com>

packages/mermaid/src/diagrams/mindmap/mindmapDb.ts

@@ -5,6 +5,7 @@ import { log } from '../../logger.js';
 import type { MindmapNode } from './mindmapTypes.js';
 import defaultConfig from '../../defaultConfig.js';
 import type { LayoutData, Node, Edge } from '../../rendering-util/types.js';
+import { getUserDefinedConfig } from '../../config.js';
 
 // Extend Node type for mindmap-specific properties
 export type MindmapLayoutNode = Node & {
@@ -325,11 +326,21 @@ export class MindmapDB {
     const mindmapRoot = this.getMindmap();
     const config = getConfig();
 
+    const userDefinedConfig = getUserDefinedConfig();
+    const hasUserDefinedLayout = userDefinedConfig.layout !== undefined;
+
+    const finalConfig = { ...config };
+    if (!hasUserDefinedLayout) {
+      finalConfig.layout = 'cose-bilkent';
+    } else {
+      finalConfig.layout = userDefinedConfig.layout;
+    }
+
     if (!mindmapRoot) {
       return {
         nodes: [],
         edges: [],
-        config,
+        config: finalConfig,
       };
     }
     log.debug('getData: mindmapRoot', mindmapRoot, config);
@@ -362,7 +373,7 @@ export class MindmapDB {
     return {
       nodes: processedNodes,
       edges: processedEdges,
-      config,
+      config: finalConfig,
       // Store the root node for mindmap-specific layout algorithms
       rootNode: mindmapRoot,
       // Properties required by dagre layout algorithm

packages/mermaid/src/diagrams/mindmap/mindmapRenderer.ts

@@ -32,7 +32,7 @@ function _updateNodeDimensions(data4Layout: LayoutData, mindmapRoot: FilledMindM
 
 export const draw: DrawDefinition = async (text, id, _version, diagObj) => {
   log.debug('Rendering mindmap diagram\n' + text);
-  const { securityLevel, mindmap: conf, layout } = getConfig();
+  const { securityLevel, mindmap: conf } = getConfig();
 
   // Draw the nodes first to get their dimensions, then update the layout data
   const db = diagObj.db as MindmapDB;
@@ -45,7 +45,7 @@ export const draw: DrawDefinition = async (text, id, _version, diagObj) => {
   const svg = getDiagramElement(id, securityLevel);
 
   data4Layout.type = diagObj.type;
-  data4Layout.layoutAlgorithm = getRegisteredLayoutAlgorithm(layout, {
+  data4Layout.layoutAlgorithm = getRegisteredLayoutAlgorithm(data4Layout.config.layout, {
     fallback: 'cose-bilkent',
   });
   // For mindmap diagrams, prioritize mindmap-specific layout algorithm configuration

packages/mermaid/src/preprocess.ts

@@ -1,5 +1,4 @@
 import { cleanupComments } from './diagram-api/comments.js';
-import { detectType } from './diagram-api/detectType.js';
 import { extractFrontMatter } from './diagram-api/frontmatter.js';
 import type { DiagramMetadata } from './diagram-api/types.js';
 import utils, { cleanAndMerge, removeDirectives } from './utils.js';
@@ -19,7 +18,6 @@ const cleanupText = (code: string) => {
 
 const processFrontmatter = (code: string) => {
   const { text, metadata } = extractFrontMatter(code);
-  const diagramType = detectType(text);
   const { displayMode, title, config = {} } = metadata;
   if (displayMode) {
     // Needs to be supported for legacy reasons
@@ -28,9 +26,7 @@ const processFrontmatter = (code: string) => {
     }
     config.gantt.displayMode = displayMode;
   }
-  if (diagramType === 'mindmap' && !config.layout) {
-    config.layout = 'cose-bilkent'; // Default layout for mindmap
-  }
+
   return { title, config, text };
 };