frontend: autograder fails to load submission details

[mewilker]

Every once and a while, The autograder loads up like this:

In this state, clicking things loads empty boxes, and student search doesn't work. You can click the submission refresh button, and it fixes some of the problem:

All data is loaded, and you can click on the blank boxes to see it. It doesn't fix the student search bar. Refreshing the page takes the whole page back to normal, so this isn't a high priority bug.

I don't know what's causing it, but I've never noticed this particularly before Spring 2025. I've been able to replicate the bug in production by closing the tab a few times and reopening it. It doesn't always happen, so you may need to try it a few times. I'm not sure if it's repeatable in a development environment.

[Maillman]

The Issue

I looked into this a little bit and I was able to pinpoint where the problem was and how to replicate the issue.

Replicating the Issue

I was able to replicate the issue by inserting a bunch of dummy test data submissions. All with different net IDs. I did this by writing the following code in the SubmissionDaoTest.java file:

@Test
void insertALotOfSubmissions() throws DataAccessException {
    for(int i = 0; i < 500; i++) {
        userID = generateID();
        userDao.insertUser(generateStudentUser(userID));
        insertSubmission();
    }
}

After writing and running the test code, I was able to get the issue to show up about half of the time I refreshed the page. I opened up the Web Browser's console and saw the following error whenever this specific issue showed up.

The Cause of The Issue

The log says there was an "Uncaught TypeError: ... at renderPhaseCell from tableUtils.ts at line 13. I debugged this a little further and ended up pretty confused. I put a breakpoint on the invoking line up the call stack, and it doesn't seem to make much sense to me.
The failure and success cases for the failing line from tableUtils.ts at line 13 are pretty straightforward.

The success case:

The failure case:

As you can see, the times the issue shows up, the params.data is missing a lot of submission information that's needed, including the needed "phase" which causes the error to occur. But going up the stack trace, it seems like all the information IS there, but it's not being completely transferred over somehow. This is the line and data that's up the stack trace a frame:

And the dataToShow is the same irrespective of the succeeding OR the failing case. So I don't know what causes the issue to arise at some times and at other times not.

Further Inspection

These are just my findings after about an hour of initial inspection. It may have something to do with the "ag-grid-community" that we're using? Perhaps @webecke might have something to add here? Regardless, I will still look into this a little bit more. Hopefully, this can be something we can fix...

[webecke]

Thats a weird bug, and I'm honored to be pinged again on this project.

If I remember correctly, the renderPhaseCell gets its data passed in from the table itself, which is that dataToShow that you're looking at. But just reloading the page fixes it?

I think at the very least if we put some error handling on the function to catch when data is missing in the renderPhaseCell function, we'd at least let other things work.

[TheDavSmasher]

@webecke What would you say the error handling should do? Should it just ignore it and continue, or should it retry to get the data? I'm unsure how the data is obtained or if it can be refreshed within the function hence my question