throw error when block width is greater than column width

packages/mermaid/src/diagrams/block/blockDB.ts

@@ -92,7 +92,18 @@ export const setCssClass = function (itemIds: string, cssClassName: string) {
 const populateBlockDatabase = (_blockList: Block[], parent: Block): void => {
   const blockList = _blockList.flat();
   const children = [];
+  const columnSettingBlock = blockList.find((b) => b?.type === 'column-setting');
+  const column = columnSettingBlock?.columns ?? -1;
   for (const block of blockList) {
+    if (
+      typeof column === 'number' &&
+      column > 0 &&
+      block.type !== 'column-setting' &&
+      typeof block.widthInColumns === 'number' &&
+      block.widthInColumns > column
+    ) {
+      throw new Error(`width of block ${block.id} is greater than the column width`);
+    }
     if (block.label) {
       block.label = sanitizeText(block.label);
     }

packages/mermaid/src/diagrams/block/parser/block.spec.ts

@@ -402,6 +402,21 @@ columns 1
       const B = blocks[0];
       expect(B.styles).toContain('fill:#f9F');
     });
+    it('should throw error when block width exceeds column width', () => {
+      const str = `block-beta
+    columns 1
+    A:1
+    B:2
+    C:3
+    D:4
+    E:3
+    F:2
+    G:1`;
+
+      expect(() => block.parse(str)).toThrowError(
+        'width of block B is greater than the column width'
+      );
+    });
   });
 
   describe('prototype properties', function () {