[Bugfix:Submission] Fix leaderboard ranking tie by Ash092016 · Pull Request #12591 · Submitty/Submitty

Ash092016 · 2026-03-15T19:49:27Z

Why is this Change Important & Necessary?

Previously, the leaderboard assigned sequential ranks even when students had identical scores. This PR implements "Competition Ranking" (e.g., 1-2-2-4), ensuring that tied students share the same rank and that the subsequent rank skips appropriately. It also adds an automated Cypress test to verify this behavior and prevent future regressions.

What is the New Behavior?

Tie Handling: The leaderboard now compares Points, Time, and Memory metrics against the previous student. If all metrics are identical, they are assigned the same rank.
Improved Ranking Logic: Implemented competition ranking in LeaderboardTable.twig where the rank number "jumps" after a tie (e.g., if two students are tied for 1st place, the next student is ranked 3rd).
Automated Verification: Added a new test case to leaderboard_gradeable.spec.js that performs two identical student submissions and asserts that they share the same rank on the leaderboard.

What steps should a reviewer take to reproduce or test the bug or new feature?

Navigate to a gradeable with a leaderboard enabled (e.g., the "leaderboard" gradeable in the sample course).
Perform two submissions for different students that result in identical Autograding metrics (Points, Time, and Memory).
Visit the leaderboard page and observe that both students are listed with the same rank number.
Verify that the student following the tied pair has a rank that skipped an intermediate value (Competition Ranking).

Automated Testing & Documentation

This feature is covered by a new end-to-end Cypress test added to site/cypress/e2e/Cypress-Gradeable/leaderboard_gradeable.spec.js.
No additional documentation updates are required for this internal UI refinement.

Other information

This is not a breaking change.
No database migrations are included.
There are no security concerns.

…bmitty#12582

codecov · 2026-03-24T20:15:02Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 21.64%. Comparing base (9e1a364) to head (952a701).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main   #12591   +/-   ##
=========================================
  Coverage     21.64%   21.64%           
  Complexity     9654     9654           
=========================================
  Files           268      268           
  Lines         36245    36245           
  Branches        487      487           
=========================================
  Hits           7846     7846           
  Misses        27916    27916           
  Partials        483      483

Flag	Coverage Δ
autograder	`21.32% <ø> (ø)`
js	`2.04% <ø> (ø)`
migrator	`100.00% <ø> (ø)`
php	`20.66% <ø> (ø)`
python_submitty_utils	`80.08% <ø> (ø)`
submitty_daemon_jobs	`91.13% <ø> (ø)`

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Eli-J-Schwartz

Hi @Ash092016,
I tested this change locally. Here is what it looks like before your change is applied:

Here is what it looks like after your change is applied:

It seems like although your change is working correctly (as seen in the tie for 1st place), the way you are detecting differences in memory and time usage is more precise than what is displayed to the user, effectively preventing most ties. Would it be possible to compare the rounded values that the user sees?

…16/Submitty into leaderboard-ranking-test

Ash092016 · 2026-03-25T21:33:30Z

Hi @Eli-J-Schwartz, the original logic was comparing the raw, highly precise backend measurements which prevented users with seemingly identical scores from tying.
I've just pushed a new commit that updates the LeaderboardTable.twig logic. It now explicitly applies the same math (round(1) for time, and converting memory to MB then rounding) before checking for ties. This ensures the ranking logic perfectly matches the formatted values displayed to the users on the leaderboard UI.

Let me know if there's anything else I should work upon!

Eli-J-Schwartz

I tested this PR again, and the changes are working correctly:

Additionally, I reviewed the code, and the functional changes appear to be free of bugs.

Please fix any remaining test errors, and then I will approve the PR.

…16/Submitty into leaderboard-ranking-test

Ash092016 · 2026-03-27T18:00:47Z

Hi @Eli-J-Schwartz, pushed fixes for the PR title length, the Cypress ESLint warning, and the leaderboard test timeout. Ready for review!

Eli-J-Schwartz

All tests are now passing, other that known test failures on the current main branch.
Everything else is the same as my last review.

### Why is this Change Important & Necessary? Fixes Submitty#12582. Previously, the leaderboard assigned sequential ranks even when students had identical scores. This PR implements "Competition Ranking" (e.g., 1-2-2-4), ensuring that tied students share the same rank and that the subsequent rank skips appropriately. It also adds an automated Cypress test to verify this behavior and prevent future regressions. ### What is the New Behavior? - **Tie Handling**: The leaderboard now compares Points, Time, and Memory metrics against the previous student. If all metrics are identical, they are assigned the same rank. - **Improved Ranking Logic**: Implemented competition ranking in [LeaderboardTable.twig](cci:7://file:///c:/Users/BIT/Desktop/Submitty/site/app/templates/submission/homework/leaderboard/LeaderboardTable.twig:0:0-0:0) where the rank number "jumps" after a tie (e.g., if two students are tied for 1st place, the next student is ranked 3rd). - **Automated Verification**: Added a new test case to [leaderboard_gradeable.spec.js](cci:7://file:///c:/Users/BIT/Desktop/Submitty/site/cypress/e2e/Cypress-Gradeable/leaderboard_gradeable.spec.js:0:0-0:0) that performs two identical student submissions and asserts that they share the same rank on the leaderboard. ### What steps should a reviewer take to reproduce or test the bug or new feature? 1. Navigate to a gradeable with a leaderboard enabled (e.g., the "leaderboard" gradeable in the sample course). 2. Perform two submissions for different students that result in identical Autograding metrics (Points, Time, and Memory). 3. Visit the leaderboard page and observe that both students are listed with the same rank number. 4. Verify that the student following the tied pair has a rank that skipped an intermediate value (Competition Ranking). ### Automated Testing & Documentation - This feature is covered by a new end-to-end Cypress test added to [site/cypress/e2e/Cypress-Gradeable/leaderboard_gradeable.spec.js](cci:7://file:///c:/Users/BIT/Desktop/Submitty/site/cypress/e2e/Cypress-Gradeable/leaderboard_gradeable.spec.js:0:0-0:0). - No additional documentation updates are required for this internal UI refinement. ### Other information - This is not a breaking change. - No database migrations are included. - There are no security concerns. --------- Co-authored-by: Justin Manion <[email protected]>

Implement competition ranking for leaderboard and add Cypress test Su…

2aa0531

…bmitty#12582

github-project-automation Bot added this to Submitty Development Mar 15, 2026

github-project-automation Bot moved this to Seeking Reviewer in Submitty Development Mar 15, 2026

Ash092016 and others added 3 commits March 16, 2026 01:19

Merge branch 'main' into leaderboard-ranking-test

d7a5b10

Merge branch 'main' into leaderboard-ranking-test

8d71cf6

Merge branch 'main' into leaderboard-ranking-test

970aee4

Eli-J-Schwartz requested changes Mar 24, 2026

View reviewed changes

github-project-automation Bot moved this from Seeking Reviewer to Work in Progress in Submitty Development Mar 24, 2026

Ash092016 added 2 commits March 26, 2026 03:00

Round time and memory before leaderboard tie comparisons

3468dbe

Merge branch 'leaderboard-ranking-test' of https://github.com/Ash0920…

1c2e3fd

…16/Submitty into leaderboard-ranking-test

Merge branch 'main' into leaderboard-ranking-test

ee485b7

Ash092016 requested a review from Eli-J-Schwartz March 25, 2026 21:33

automateprojectmangement Bot moved this from Work in Progress to In Review in Submitty Development Mar 25, 2026

Eli-J-Schwartz requested changes Mar 26, 2026

View reviewed changes

github-project-automation Bot moved this from In Review to Work in Progress in Submitty Development Mar 26, 2026

Ash092016 changed the title ~~[Bugfix:Submission] Correct leaderboard competition ranking logic~~ [Bugfix:Submission] Fix leaderboard ranking tie Mar 27, 2026

Ash092016 added 3 commits March 27, 2026 23:22

Fix Cypress test timeout and ESLint warning

a34714e

Merge branch 'leaderboard-ranking-test' of https://github.com/Ash0920…

ceb8773

…16/Submitty into leaderboard-ranking-test

Merge branch 'main' into leaderboard-ranking-test

952a701

Ash092016 requested a review from Eli-J-Schwartz March 27, 2026 18:00

automateprojectmangement Bot moved this from Work in Progress to In Review in Submitty Development Mar 27, 2026

Eli-J-Schwartz approved these changes Mar 27, 2026

View reviewed changes

github-project-automation Bot moved this from In Review to Awaiting Maintainer Review in Submitty Development Mar 27, 2026

bmcutler merged commit 2aa745d into Submitty:main Mar 27, 2026
24 of 26 checks passed

GarvitKhandelwal31 mentioned this pull request Mar 30, 2026

Fix failing leaderboard gradeable test #12683

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[Bugfix:Submission] Fix leaderboard ranking tie#12591

[Bugfix:Submission] Fix leaderboard ranking tie#12591
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Ash092016 commented Mar 15, 2026

Why is this Change Important & Necessary?

What is the New Behavior?

What steps should a reviewer take to reproduce or test the bug or new feature?

Automated Testing & Documentation

Other information

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