fix: prevent pie chart crash on zero or negative values

packages/mermaid/src/diagrams/pie/pie.spec.ts

@@ -139,6 +139,24 @@ describe('pie', () => {
       }).rejects.toThrowError();
     });
 
+    it('should handle simple pie with zero slice value', async () => {
+      await expect(async () => {
+        await parser.parse(`pie
+        "ash" : 0
+        "bat" : 40.12
+        `);
+      }).rejects.toThrowError();
+    });
+
+    it('should handle simple pie with negative slice value', async () => {
+      await expect(async () => {
+        await parser.parse(`pie
+        "ash" : -60
+        "bat" : 40.12
+        `);
+      }).rejects.toThrowError();
+    });
+
     it('should handle unsafe properties', async () => {
       await expect(
         parser.parse(`pie title Unsafe props test

packages/mermaid/src/diagrams/pie/pieDb.ts

@@ -34,6 +34,17 @@ const clear = (): void => {
 };
 
 const addSection = ({ label, value }: D3Section): void => {
+  if (value <= 0) {
+    const error: any = new Error(
+      `Section "${label}" has invalid value: ${value}. Zero and negative values are not allowed in pie charts. All slice values must be > 0`
+    );
+    error.hash = {
+      text: `pie "${label}": ${value}`,
+      token: `${value}`,
+      expected: ['a positive number (> 0)'],
+    };
+    throw error;
+  }
   if (!sections.has(label)) {
     sections.set(label, value);
     log.debug(`added new section: ${label}, with value: ${value}`);

packages/mermaid/src/docs/syntax/pie.md

@@ -24,6 +24,11 @@ Drawing a pie chart is really simple in mermaid.
   - Followed by `:` colon as separator
   - Followed by `positive numeric value` (supported up to two decimal places)
 
+**Note:**
+
+> Pie chart values must be **positive numbers greater than zero**.  
+> **Zero and negative values are not allowed** and will result in an error.
+
 [pie] [showData] (OPTIONAL)
 [title] [titlevalue] (OPTIONAL)
 "[datakey1]" : [dataValue1]

packages/parser/src/language/common/common.langium

@@ -17,8 +17,8 @@ terminal ACC_DESCR: /[\t ]*accDescr(?:[\t ]*:([^\n\r]*?(?=%%)|[^\n\r]*)|\s*{([^}
 terminal ACC_TITLE: /[\t ]*accTitle[\t ]*:(?:[^\n\r]*?(?=%%)|[^\n\r]*)/;
 terminal TITLE: /[\t ]*title(?:[\t ][^\n\r]*?(?=%%)|[\t ][^\n\r]*|)/;
 
-terminal FLOAT returns number: /[0-9]+\.[0-9]+(?!\.)/;
-terminal INT returns number: /0|[1-9][0-9]*(?!\.)/;
+terminal FLOAT returns number: /-?[0-9]+\.[0-9]+(?!\.)/;
+terminal INT returns number: /-?(0|[1-9][0-9]*)(?!\.)/;
 terminal NUMBER returns number: FLOAT | INT;
 
 terminal STRING returns string: /"([^"\\]|\\.)*"|'([^'\\]|\\.)*'/;