Submission source missing

[ntm97]

Description of the problem

At GCPC, we encountered a submission where the /jury/submissions/<submitid>/source route just showed a blank page:

The submission was judged as correct and it also has compilation metadata and output that indicates it was not an empty file:

M.cpp: In function 'bool check(std::vector<long int>&, i64)':
M.cpp:11:14: warning: comparison of integer expressions of different signedness: 'i64' {aka 'long int'} and 'std::vector<long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |     while (i < ids.size()) {
      |            ~~^~~~~~~~~~~~
M.cpp:16:18: warning: comparison of integer expressions of different signedness: 'i64' {aka 'long int'} and 'std::vector<long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |         while (j < ids.size() && ids[j+1] < ids[i] + d)
      |                ~~^~~~~~~~~~~~
M.cpp: In function 'int main()':
M.cpp:32:9: warning: unused variable 'm' [-Wunused-variable]
   32 |     i64 m = 0;
      |         ^

Your environment

• DOMjudge version: b32fc5c8c5a84160e6e26203228fbbe1ec8444e9 with 028995f9c00e7897ec863283986ef995661e38b9 cherry-picked on top of that
• Operating system / Linux distribution and version: Debian GNU/Linux 12 (bookworm), 6.1.0-27-amd64
• Webserver: nginx/1.22.1

Steps to reproduce

Not sure how to reproduce this, as this is the only time this has ever happened to us.

Expected behaviour

The actual source code of the submission should be displayed.

Actual behaviour

An empty page is displayed.

Any other information that you want to share?

The source code of the submission seems to be present in the database, so I'm not sure why it fails to display it:

MariaDB [domjudge]> select * from submission where submitid = 13616;
+----------+--------------+------+--------+--------+--------+--------+----------------------+-------+-------------+------------------+------------+-------------+--------------+
| submitid | origsubmitid | cid  | teamid | userid | probid | langid | submittime           | valid | rejudgingid | expected_results | externalid | entry_point | import_error |
+----------+--------------+------+--------+--------+--------+--------+----------------------+-------+-------------+------------------+------------+-------------+--------------+
|    13616 |         NULL |   16 |    678 |    691 |    296 | cpp    | 1751721909.516700000 |     1 |        NULL | NULL             | 13616      | NULL        | NULL         |
+----------+--------------+------+--------+--------+--------+--------+----------------------+-------+-------------+------------------+------------+-------------+--------------+
1 row in set (0.000 sec)

MariaDB [domjudge]> select * from submission_file where submitid = 13616;
+--------------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+------------+
| submitfileid | submitid | sourcecode                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | filename | ranknumber |
+--------------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+------------+
|        13644 |    13616 | #include <bits/stdc++.h>
using namespace std;
typedef int64_t i64;

i64 n, d;

bool check(vector<i64>& ids, i64 D) {
    // check if all Ds can be excluded
    i64 earliest = 0;
    i64 i = 0;
    while (i < ids.size()) {
        if (ids[i] < earliest)
            return false;
        // find all that are covered by [id,id+d-1]
        i64 j = i;
        while (j < ids.size() && ids[j+1] < ids[i] + d)
            j++;
        // find start spot
        i64 start = max(earliest,ids[j]-d+1);
        // update
        i = j+1;
        earliest = start + 2*d;
    }
    return true;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    i64 x;
    cin >> n >> d;
    vector<vector<i64>> indices(n);
    i64 m = 0;
    for (i64 i = 0; i < n; i++) {
        cin >> x;
        indices[x].push_back(i);
    }


    i64 D = 0;
    while (D < n && !check(indices[D],D)) {
        D++;
    }
    cout << D << "\n";
} | M.cpp    |          0 |
+--------------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+------------+
1 row in set (0.000 sec)

[vmcj]

Can you provide 13616 & 130507? I think I've seen this before but did not investigate at that time.

If it's possible a DB dump would also help, so I can play around with it a bit easier.

[ntm97]

MariaDB [domjudge]> select * from submission where submitid in (13616, 13507);
+----------+--------------+------+--------+--------+--------+--------+----------------------+-------+-------------+------------------+------------+-------------+--------------+
| submitid | origsubmitid | cid  | teamid | userid | probid | langid | submittime           | valid | rejudgingid | expected_results | externalid | entry_point | import_error |
+----------+--------------+------+--------+--------+--------+--------+----------------------+-------+-------------+------------------+------------+-------------+--------------+
|    13507 |         NULL |   16 |    678 |    691 |    296 | cpp    | 1751720679.266900000 |     1 |        NULL | NULL             | 13507      | NULL        | NULL         |
|    13616 |         NULL |   16 |    678 |    691 |    296 | cpp    | 1751721909.516700000 |     1 |        NULL | NULL             | 13616      | NULL        | NULL         |
+----------+--------------+------+--------+--------+--------+--------+----------------------+-------+-------------+------------------+------------+-------------+--------------+
2 rows in set (0.000 sec)

MariaDB [domjudge]> select * from submission_file where submitid in (13616, 13507);
+--------------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+------------+
| submitfileid | submitid | sourcecode                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | filename | ranknumber |
+--------------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+------------+
|        13535 |    13507 | #include <bits/stdc++.h>
using namespace std;
typedef int64_t i64;

i64 n, d;

bool check(vector<i64>& ids, i64 D) {
    // check if all Ds can be excluded
    i64 earliest = 0;
    i64 i = 0;
    while (i < ids.size()) {
        if (ids[i] < earliest)
            return false;
        // find all that are covered by [id,id+d-1]
        i64 j = i;
        while (j < ids.size() && ids[j+1] < ids[i] + d)
            j++;
        // find start spot
        i64 start = max(earliest,ids[j]-d+1);
        // update
        i = j+1;
        earliest = start + 2*d;
    }
    return true;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    i64 x;
    cin >> n >> d;
    vector<vector<i64>> indices(n);
    i64 m = 0;
    for (i64 i = 0; i < n; i++) {
        cin >> x;
        indices[x].push_back(i);
    }


    i64 D = 0;
    while (D < n && !check(indices[D],D)) {
        D++;
    }
    cout << D << "\n";
} | M.cpp    |          0 |
|        13644 |    13616 | #include <bits/stdc++.h>
using namespace std;
typedef int64_t i64;

i64 n, d;

bool check(vector<i64>& ids, i64 D) {
    // check if all Ds can be excluded
    i64 earliest = 0;
    i64 i = 0;
    while (i < ids.size()) {
        if (ids[i] < earliest)
            return false;
        // find all that are covered by [id,id+d-1]
        i64 j = i;
        while (j < ids.size() && ids[j+1] < ids[i] + d)
            j++;
        // find start spot
        i64 start = max(earliest,ids[j]-d+1);
        // update
        i = j+1;
        earliest = start + 2*d;
    }
    return true;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    i64 x;
    cin >> n >> d;
    vector<vector<i64>> indices(n);
    i64 m = 0;
    for (i64 i = 0; i < n; i++) {
        cin >> x;
        indices[x].push_back(i);
    }


    i64 D = 0;
    while (D < n && !check(indices[D],D)) {
        D++;
    }
    cout << D << "\n";
} | M.cpp    |          0 |
+--------------+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+------------+
2 rows in set (0.000 sec)

The entire DB dump would probably be > 1.5Gb.

[rry-je]

The two submissions are bytewise identical:

MariaDB [domjudge]> SELECT submitfileid, submitid, MD5(sourcecode), filename, ranknumber FROM submission_file WHERE submitid IN (13616, 13507);
+--------------+----------+----------------------------------+----------+------------+
| submitfileid | submitid | MD5(sourcecode)                  | filename | ranknumber |
+--------------+----------+----------------------------------+----------+------------+
|        13535 |    13507 | 9c229d1ad49d5619499eefdf3171a315 | M.cpp    |          0 |
|        13644 |    13616 | 9c229d1ad49d5619499eefdf3171a315 | M.cpp    |          0 |
+--------------+----------+----------------------------------+----------+------------+
2 rows in set (0.002 sec)

In templates/jury/partials/submission_diff.html.twig, since nothing actually changed, oldFileStats.changedfiles is empty, and no diff is displayed. Since there is a previous submission, templates/jury/submission_source.html.twig also won't display the source code without a diff.

As a quick workaround, this patch seems to work:

diff --git a/webapp/src/Controller/Jury/SubmissionController.php b/webapp/src/Controller/Jury/SubmissionController.php
index 0d6c551e1..d61f2b582 100644
--- a/webapp/src/Controller/Jury/SubmissionController.php
+++ b/webapp/src/Controller/Jury/SubmissionController.php
@@ -1226,10 +1226,10 @@ class SubmissionController extends BaseController
                     if ($oldFile->getSourcecode() === $newfile->getSourcecode()) {
                         $result['unchanged'][] = $newfile->getFilename();
                     } else {
                         $result['changed'][]      = $newfile->getFilename();
-                        $result['changedfiles'][] = [$newfile, $oldFile];
                     }
+                    $result['changedfiles'][] = [$newfile, $oldFile]; // Otherwise nothing is visible if a team submits the same code twice
                 }
             }
         }