fix(gantt): limit loop if excluding all dates

Add an iteration limit to `fixTaskDates` to prevent infinite loops
(i.e. when `excludes` is used to exclude every possible date).

I've picked 10k days, in case some users are using `dateFormat` and
`excludes` to exclude entire years, since 10k days is 27 years, and
anything above that starts to have noticable lag.

Author: aloisklink

.changeset/common-parents-serve.md

@@ -0,0 +1,5 @@
+---
+'mermaid': patch
+---
+
+fix(gantt): add iteration limit for `excludes` field

packages/mermaid/src/diagrams/gantt/ganttDb.js

@@ -245,21 +245,28 @@ const checkTaskDates = function (task, dateFormat, excludes, includes) {
  * @param {dayjs.Dayjs} startTime - The start time.
  * @param {dayjs.Dayjs} endTime - The original end time (will return a different end time if it's invalid).
  * @param {string} dateFormat - Dayjs date format string.
- * @param {*} excludes
- * @param {*} includes
+ * @param {string[]} excludes - Dates or days to exclude.
+ * @param {string[]} includes - Dates to always include, even if they match the excludes.
  * @returns {[endTime: dayjs.Dayjs, renderEndTime: Date | null]} The new `endTime`, and the end time to render.
  * `renderEndTime` may be `null` if `startTime` is newer than `endTime`.
+ * @throws {Error} If a valid end time cannot be found after 10,000 iterations.
  */
 const fixTaskDates = function (startTime, endTime, dateFormat, excludes, includes) {
   let invalid = false;
   let renderEndTime = null;
+  const maxEndTime = endTime.add(10000, 'd');
   while (startTime <= endTime) {
     if (!invalid) {
       renderEndTime = endTime.toDate();
     }
     invalid = isInvalidDate(startTime, dateFormat, excludes, includes);
     if (invalid) {
       endTime = endTime.add(1, 'd');
+      if (endTime > maxEndTime) {
+        throw new Error(
+          'Failed to find a valid date that was not excluded by `excludes` after 10,000 iterations.'
+        );
+      }
     }
     startTime = startTime.add(1, 'd');
   }

packages/mermaid/src/diagrams/gantt/ganttDb.spec.ts

@@ -282,6 +282,20 @@ describe('when using the ganttDb', function () {
     expect(tasks[0].task).toEqual('test1');
   });
 
+  it('should not infinite loop when excluding everything', function () {
+    ganttDb.setDateFormat('YYYY-MM-DD');
+    ganttDb.setExcludes('weekends,monday,tuesday,wednesday,thursday,friday');
+    ganttDb.setWeekend('saturday');
+    ganttDb.addSection('weekends skip test');
+    ganttDb.addTask('test1', 'id1,2019-02-01,7d');
+
+    expect(() => ganttDb.getTasks()).toThrowError('Failed to find a valid date');
+
+    // Fridays are now allowed, so it should not throw an error
+    ganttDb.setExcludes('weekends,monday,tuesday,wednesday,thursday');
+    expect(() => ganttDb.getTasks()).not.toThrow();
+  });
+
   it('should maintain the order in which tasks are created', function () {
     ganttDb.setAccTitle('Project Execution');
     ganttDb.setDateFormat('YYYY-MM-DD');