From b70be33025011976d8c3fb87e0bdd6bc66c198d0 Mon Sep 17 00:00:00 2001
From: Kevin Jilissen <info@kevinjilissen.nl>
Date: Wed, 1 Oct 2025 22:24:50 +0200
Subject: [PATCH 1/4] Change source fetching to single query

Also removes some redundant twig variables and prepares the logic for
more submissions to diff against.
---
 .../Controller/Jury/SubmissionController.php  | 47 +++++++++----------
 .../jury/submission_source.html.twig          |  4 +-
 2 files changed, 24 insertions(+), 27 deletions(-)

diff --git a/webapp/src/Controller/Jury/SubmissionController.php b/webapp/src/Controller/Jury/SubmissionController.php
index acca869506..95cc7d0294 100644
--- a/webapp/src/Controller/Jury/SubmissionController.php
+++ b/webapp/src/Controller/Jury/SubmissionController.php
@@ -849,22 +849,10 @@ public function sourceAction(
             ->getQuery()
             ->getResult();
 
-        $originalSubmission = $originalFiles = null;
-
-        if ($submission->getOriginalSubmission()) {
-            /** @var Submission $originalSubmission */
-            $originalSubmission = $this->em->getRepository(Submission::class)->find($submission->getOriginalSubmission()->getSubmitid());
-
-            /** @var SubmissionFile[] $files */
-            $originalFiles = $this->em->createQueryBuilder()
-                ->from(SubmissionFile::class, 'file')
-                ->select('file')
-                ->andWhere('file.submission = :submission')
-                ->setParameter('submission', $originalSubmission)
-                ->orderBy('file.ranknumber')
-                ->getQuery()
-                ->getResult();
-
+        $otherSubmissions = [];
+        $originalSubmission = $submission->getOriginalSubmission();
+        if ($originalSubmission) {
+            $otherSubmissions[] = $originalSubmission;
             /** @var Submission $oldSubmission */
             $oldSubmission = $this->em->createQueryBuilder()
                 ->from(Submission::class, 's')
@@ -900,30 +888,39 @@ public function sourceAction(
                 ->getQuery()
                 ->getOneOrNullResult();
         }
+        if ($oldSubmission !== null) {
+            $otherSubmissions[] = $oldSubmission;
+        }
 
         /** @var SubmissionFile[] $files */
         $oldFiles = $this->em->createQueryBuilder()
             ->from(SubmissionFile::class, 'file')
             ->select('file')
-            ->andWhere('file.submission = :submission')
-            ->setParameter('submission', $oldSubmission)
-            ->orderBy('file.ranknumber')
+            ->andWhere('file.submission in (:submissions)')
+            ->setParameter('submissions', array_map(fn($s) => $s->getSubmitid(), $otherSubmissions))
+            ->orderBy('file.submission, file.ranknumber')
             ->getQuery()
             ->getResult();
 
-        $oldFileStats      = $oldFiles !== null ? $this->determineFileChanged($files, $oldFiles) : [];
-        $originalFileStats = $originalFiles !== null ? $this->determineFileChanged($files, $originalFiles) : [];
+        $otherFiles = [];
+        foreach ($oldFiles as $f) {
+            $submitId = $f->getSubmission()->getSubmitid();
+            $otherFiles[$submitId] ??= [];
+            $otherFiles[$submitId][] = $f;
+        }
+
+        foreach ($otherFiles as $s => $v) {
+            $otherFiles[$s] = $this->determineFileChanged($files, $v);
+        }
 
         return $this->render('jury/submission_source.html.twig', [
             'submission' => $submission,
             'files' => $files,
             'oldSubmission' => $oldSubmission,
-            'oldFiles' => $oldFiles,
-            'oldFileStats' => $oldFileStats,
             'originalSubmission' => $originalSubmission,
-            'originalFiles' => $originalFiles,
-            'originalFileStats' => $originalFileStats,
             'allowEdit' => $this->allowEdit(),
+            'otherSubmissions' => $otherSubmissions,
+            'otherFiles' => $otherFiles,
         ]);
     }
 
diff --git a/webapp/templates/jury/submission_source.html.twig b/webapp/templates/jury/submission_source.html.twig
index 2ddcf2b4c5..dba2b6cd92 100644
--- a/webapp/templates/jury/submission_source.html.twig
+++ b/webapp/templates/jury/submission_source.html.twig
@@ -42,7 +42,7 @@
     {%- endif %}
 
     {% if oldSubmission %}
-        {%- include 'jury/partials/submission_diff.html.twig' with {oldSubmission: oldSubmission, oldFiles: oldFiles, oldFileStats: oldFileStats} %}
+        {%- include 'jury/partials/submission_diff.html.twig' with {oldSubmission: oldSubmission, oldFileStats: otherFiles[oldSubmission.submitid]} %}
     {% else %}
         <ul class="nav nav-tabs source-tab-nav">
             {%- for file in files %}
@@ -84,7 +84,7 @@
             </a>
         </h2>
 
-        {%- include 'jury/partials/submission_diff.html.twig' with {oldSubmission: originalSubmission, oldFiles: originalFiles, oldFileStats: originalFileStats} %}
+        {%- include 'jury/partials/submission_diff.html.twig' with {oldSubmission: originalSubmission, oldFileStats: otherFiles[originalSubmission.submitid]} %}
     {%- endif %}
 
 {% endblock %}
\ No newline at end of file

From 1de61c5fc309e201aa245b9b200b880b9e3ca654 Mon Sep 17 00:00:00 2001
From: Kevin Jilissen <info@kevinjilissen.nl>
Date: Fri, 3 Oct 2025 00:12:39 +0200
Subject: [PATCH 2/4] Switch diff viewers to single viewer

Render the diff viewers for a submission as if it was a single IDE, in
which you can select the submission to diff against. We move the button
interface out of the tabs and create functions to update the state of
individual enditors.
---
 webapp/public/js/domjudge.js                  | 167 ++++++++++++++++++
 .../Controller/Jury/SubmissionController.php  |   4 -
 webapp/src/Twig/TwigExtension.php             |  86 ++++-----
 .../jury/partials/submission_diff.html.twig   | 135 +++++---------
 .../jury/submission_source.html.twig          |  20 +--
 5 files changed, 244 insertions(+), 168 deletions(-)

diff --git a/webapp/public/js/domjudge.js b/webapp/public/js/domjudge.js
index 371ae20e92..05d014cefc 100644
--- a/webapp/public/js/domjudge.js
+++ b/webapp/public/js/domjudge.js
@@ -1290,3 +1290,170 @@ function initScoreboardSubmissions() {
         });
     });
 }
+
+const editors = [];
+function initDiffEditor(editorId) {
+    const wrapper = $(`#${editorId}-wrapper`);
+
+    // TODO: store and restore tag preference in local storage.
+    const initialSelect = "";
+    const select = wrapper.find(".diff-select");
+    select[0].selectedIndex = 0;
+
+    const initialDiffMode = getDiffMode();
+    const radios = wrapper.find(`.diff-mode > input[type='radio']`);
+    radios.each((_, radio) => {
+        radio.checked = radio.value === initialDiffMode
+    });
+
+    const download = wrapper.find(".download")[0];
+    const edit = wrapper.find(".edit")[0];
+    const updateTabRank = (rank) => {
+        if (rank) {
+            let url = new URL(download.href);
+            url.searchParams.set("fetch", rank);
+            download.href = url;
+
+            url = new URL(edit.href);
+            url.searchParams.set("rank", rank);
+            edit.href = url;
+        } else {
+            download.href = "#";
+            edit.href = "#";
+        }
+    };
+    wrapper.find(".nav").on('show.bs.tab', (e) => {
+        updateTabRank(e.target.dataset.rank);
+    })
+
+    const editor = {
+        'getDiffMode': () => {
+            for (let radio of radios) {
+                if (radio.checked) {
+                    return radio.value;
+                }
+            }
+        },
+        'getDiffSelection': () => {
+            let s = select[0];
+            return s.options[s.selectedIndex].value;
+        },
+        'updateIcon': (rank, icon) => {
+            const element = wrapper.find(".nav-link[data-rank]")[rank].querySelector('.fa-fw');
+            element.className = 'fas fa-fw fa-' + icon;
+        },
+        'onDiffModeChange': (f) => {
+            radios.change((e) => {
+                const diffMode = e.target.value;
+                f(diffMode);
+            });
+        },
+        'onDiffSelectChange': (f) => {
+            select.change((e) => {
+                const submitId = e.target.value;
+                const noDiff = submitId === "";
+                f(submitId, noDiff);
+            });
+        }
+    };
+    editors[editorId] = editor;
+
+    const updateMode = (diffMode) => {
+        setDiffMode(diffMode);
+    };
+    updateMode(initialDiffMode);
+    editor.onDiffModeChange(updateMode);
+
+    const updateSelect = (submitId, noDiff) => {
+        radios.each((_, radio) => {
+            radio.disabled = noDiff;
+        });
+        // TODO: add tab panes for deleted source files.
+    };
+    updateSelect("", true);
+    editor.onDiffSelectChange(updateSelect);
+}
+
+function initDiffEditorTab(editorId, diffId, rank, models, modifiedModel) {
+    const empty = monaco.editor.getModel(monaco.Uri.file("empty")) ?? monaco.editor.createModel("", undefined, monaco.Uri.file("empty"));
+
+    const diffEditor = monaco.editor.createDiffEditor(
+        document.getElementById(diffId), {
+        scrollbar: {
+            alwaysConsumeMouseWheel: false,
+            vertical: 'auto',
+            horizontal: 'auto'
+        },
+        scrollBeyondLastLine: false,
+        automaticLayout: true,
+        readOnly: true,
+        theme: getCurrentEditorTheme(),
+    });
+
+    const updateSelect = (submitId, noDiff) => {
+        if (!noDiff) {
+            const model = models[submitId];
+            if (model === undefined) {
+                models[submitId] = {'model': empty};
+            } else if (model !== undefined && !model['model']) {
+                // TODO: show source code instead of diff to empty file?
+                model['model'] = monaco.editor.createModel(model['source'], undefined, monaco.Uri.file("test/" + submitId + "/" + model['filename']));
+            }
+        }
+
+        diffEditor.updateOptions({
+            renderOverviewRuler: !noDiff,
+        });
+        if (noDiff) {
+            diffEditor.updateOptions({
+                renderSideBySide: false,
+            });
+        } else {
+            // Reset the diff mode to the currently selected mode.
+            updateMode(editors[editorId].getDiffMode())
+        }
+        // TODO: handle single-file submission case with renamed file.
+        const oldViewState = diffEditor.saveViewState();
+        diffEditor.setModel({
+            original: noDiff ? modifiedModel : models[submitId]['model'],
+            modified: modifiedModel,
+        });
+        diffEditor.restoreViewState(oldViewState);
+
+        diffEditor.getOriginalEditor().updateOptions({
+            lineNumbers: !noDiff,
+        });
+        diffEditor.getModifiedEditor().updateOptions({
+            minimap: {
+                enabled: noDiff,
+            },
+        })
+    };
+    editors[editorId].onDiffSelectChange(updateSelect);
+    updateSelect("", true);
+
+    const updateIcon = () => {
+        const noDiff = editors[editorId].getDiffSelection() === "";
+        if (noDiff) {
+            editors[editorId].updateIcon(rank, 'file');
+            return;
+        }
+
+        const lineChanges = diffEditor.getLineChanges();
+        if (diffEditor.getModel().original == empty) {
+            editors[editorId].updateIcon(rank, 'file-circle-plus');
+        } else if (lineChanges !== null && lineChanges.length > 0) {
+            editors[editorId].updateIcon(rank, 'file-circle-exclamation');
+        } else {
+            editors[editorId].updateIcon(rank, 'file-circle-check');
+        }
+    }
+    diffEditor.onDidUpdateDiff(updateIcon);
+
+    const updateMode = (diffMode) => {
+        diffEditor.updateOptions({
+            renderSideBySide: diffMode === 'side-by-side',
+        });
+    };
+    editors[editorId].onDiffModeChange(updateMode);
+}
\ No newline at end of file
diff --git a/webapp/src/Controller/Jury/SubmissionController.php b/webapp/src/Controller/Jury/SubmissionController.php
index 95cc7d0294..038f12ced4 100644
--- a/webapp/src/Controller/Jury/SubmissionController.php
+++ b/webapp/src/Controller/Jury/SubmissionController.php
@@ -909,10 +909,6 @@ public function sourceAction(
             $otherFiles[$submitId][] = $f;
         }
 
-        foreach ($otherFiles as $s => $v) {
-            $otherFiles[$s] = $this->determineFileChanged($files, $v);
-        }
-
         return $this->render('jury/submission_source.html.twig', [
             'submission' => $submission,
             'files' => $files,
diff --git a/webapp/src/Twig/TwigExtension.php b/webapp/src/Twig/TwigExtension.php
index c1309fe6b7..7dfb75b13e 100644
--- a/webapp/src/Twig/TwigExtension.php
+++ b/webapp/src/Twig/TwigExtension.php
@@ -34,6 +34,7 @@
 use Symfony\Component\Routing\RouterInterface;
 use Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorageInterface;
 use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
+use Symfony\Component\Serializer\SerializerInterface;
 use Twig\Environment;
 use Twig\Extension\AbstractExtension;
 use Twig\Extension\GlobalsInterface;
@@ -57,6 +58,7 @@ public function __construct(
         protected readonly TokenStorageInterface $tokenStorage,
         protected readonly AuthorizationCheckerInterface $authorizationChecker,
         protected readonly RouterInterface $router,
+        protected readonly SerializerInterface $serializer,
         #[Autowire('%kernel.project_dir%')]
         protected readonly string $projectDir,
         protected array $renderedSources = []
@@ -177,7 +179,6 @@ public function getGlobals(): array
                 'hc-black'                  => ['name' => 'High contrast (dark)'],
             ],
             'diff_modes'                    => [
-                'no-diff'                   => ["name"  => "No diff"],
                 'side-by-side'              => ["name"  => "Side-by-side"],
                 'inline'                    => ["name"  => "Inline"],
             ],
@@ -954,71 +955,44 @@ public function getMonacoModel(SubmissionFile $file): string
         );
     }
 
-    public function showDiff(string $id, SubmissionFile $newFile, SubmissionFile $oldFile): string
+    /** @param array<int, SubmissionFile[]> $otherFiles */
+    public function showDiff(string $editorId, string $diffId, SubmissionFile $newFile, array $otherFiles): string
     {
         $editor = <<<HTML
-<div class="editor" id="__EDITOR__"></div>
+<div class="editor" id="$diffId"></div>
 <script>
 $(function() {
-    require(['vs/editor/editor.main'], function () {
-        const originalModel = %s
-        const modifiedModel = %s
-
-        const initialDiffMode = getDiffMode();
-        const radios = $("#diffselect-__EDITOR__ > input[name='__EDITOR__-mode']");
-        radios.each((_, radio) => {
-            $(radio).prop('checked', radio.value === initialDiffMode);
-        });
-
-        const diffEditor = monaco.editor.createDiffEditor(
-            document.getElementById("__EDITOR__"), {
-            scrollbar: {
-                alwaysConsumeMouseWheel: false,
-                vertical: 'auto',
-                horizontal: 'auto'
-            },
-            scrollBeyondLastLine: false,
-            automaticLayout: true,
-            readOnly: true,
-            theme: getCurrentEditorTheme(),
-        });
-
-        const updateMode = (diffMode) => {
-            setDiffMode(diffMode);
-            const noDiff = diffMode === 'no-diff';
-            diffEditor.updateOptions({
-                renderOverviewRuler: !noDiff,
-                renderSideBySide: diffMode === 'side-by-side',
-            });
-
-            const oldViewState = diffEditor.saveViewState();
-            diffEditor.setModel({
-                original: noDiff ? modifiedModel : originalModel,
-                modified: modifiedModel,
-            });
-            diffEditor.restoreViewState(oldViewState);
-
-            diffEditor.getOriginalEditor().updateOptions({
-                lineNumbers: !noDiff,
-            });
-            diffEditor.getModifiedEditor().updateOptions({
-                minimap: {
-                    enabled: noDiff,
-                },
-            })
-        };
-        radios.change((e) => {
-            updateMode(e.target.value);
-        });
-        updateMode(initialDiffMode);
+    const editorId = '%s';
+    const diffId = '%s';
+    const rank = %d;
+    const models = %s;
+    require(['vs/editor/editor.main'], () => {
+        const modifiedModel = %s;
+        initDiffEditorTab(editorId, diffId, rank, models, modifiedModel)
     });
 });
 </script>
 HTML;
 
+        $others = [];
+        foreach ($otherFiles as $submissionId => $files) {
+            foreach ($files as $f) {
+                if ($f->getFilename() == $newFile->getFilename()) {
+                    // TODO: add `tag` containing `previous` / `original`
+                    $others[$submissionId] = [
+                        'filename' => $f->getFilename(),
+                        'source'   => $f->getSourcecode(),
+                    ];
+                }
+            }
+        }
+
         return sprintf(
-            str_replace('__EDITOR__', $id, $editor),
-            $this->getMonacoModel($oldFile),
+            $editor,
+            $editorId,
+            $diffId,
+            $newFile->getRank(),
+            $this->serializer->serialize($others, 'json'),
             $this->getMonacoModel($newFile),
         );
     }
diff --git a/webapp/templates/jury/partials/submission_diff.html.twig b/webapp/templates/jury/partials/submission_diff.html.twig
index 04d60dbda7..f8c94e13b4 100644
--- a/webapp/templates/jury/partials/submission_diff.html.twig
+++ b/webapp/templates/jury/partials/submission_diff.html.twig
@@ -1,112 +1,67 @@
-{% if files | length > 1 or oldFiles | length > 1 %}
-    <table class="table table-sm table-striped file-diff-table">
-        <tr>
-            <th class="diff-add">Files added</th>
-            <td class="filename">{{ oldFileStats.added | join(', ') }}</td>
-        </tr>
-        <tr>
-            <th class="diff-del">Files removed</th>
-            <td class="filename">{{ oldFileStats.removed | join(', ') }}</td>
-        </tr>
-        <tr>
-            <th class="diff-changed">Files changed</th>
-            <td class="filename">{{ oldFileStats.changed | join(', ') }}</td>
-        </tr>
-        <tr>
-            <th>Files unchanged</th>
-            <td class="filename">{{ oldFileStats.unchanged | join(', ') }}</td>
-        </tr>
-    </table>
-{% endif %}
+<div id="{{ editor_id }}-wrapper">
 {# Mark the first tab that is shown as active. #}
 {% set extra_css_classes = "active" %}
-<ul class="nav nav-tabs source-tab-nav">
-    {%- for filePair in oldFileStats.changedfiles %}
+<ul class="nav nav-tabs source-tab-nav align-items-end">
+    {%- for file in files %}
+        {% set diff_id = "diff" ~ file.submitfileid %}
         <li class="nav-item">
-            <a class="nav-link {{ extra_css_classes }}" data-bs-toggle="tab"
-               href="#diff-{{ filePair.1.submitfileid }}" role="tab">{{ filePair.0.filename }}</a>
-        </li>
-        {% set extra_css_classes = "" %}
-    {%- endfor %}
-    {%- for file in oldFileStats.unchangedfiles %}
-        <li class="nav-item">
-            <a class="nav-link {{ extra_css_classes }}" data-bs-toggle="tab"
-               href="#diff-{{ file.submitfileid }}" role="tab">{{ file.filename }}</a>
-        </li>
-        {% set extra_css_classes = "" %}
-    {%- endfor %}
-    {%- for file in oldFileStats.addedfiles %}
-        <li class="nav-item">
-            <a class="nav-link {{ extra_css_classes }}" data-bs-toggle="tab"
-               href="#diff-{{ file.submitfileid }}" role="tab">{{ file.filename }}</a>
+            <a class="nav-link {{ extra_css_classes }}" data-bs-toggle="tab" data-rank="{{ file.rank }}" href="#{{ diff_id }}-tab" role="tab"><i class="fas fa-fw fa-file"></i> {{ file.filename }}</a>
         </li>
         {% set extra_css_classes = "" %}
     {%- endfor %}
 
-</ul>
-{# Mark the first pane that is shown as active. #}
-{% set extra_css_classes = "show active" %}
-<div class="tab-content source-tab">
-    {%- for filePair in oldFileStats.changedfiles %}
-        <div class="tab-pane fade {{ extra_css_classes }}" id="diff-{{ filePair.1.submitfileid }}" role="tabpanel">
-            {% set diff_id = "diff" ~  filePair.1.submitfileid %}
-            <div class="mb-1">
-                <a class="btn btn-secondary btn-sm"
-                   href="{{ path('jury_submission_source', {submission: submission.submitid, fetch: filePair.1.rank}) }}">
+            <div class="nav-item flex-grow-1 text-end mb-1">
+                <a class="download btn btn-secondary btn-sm"
+                   href="{{ path('jury_submission_source', {submission: submission.submitid, fetch: 0}) }}">
                     <i class="fas fa-download"></i> Download
                 </a>
                 {% if allowEdit %}
-                    <a class="btn btn-secondary btn-sm"
-                       href="{{ path('jury_submission_edit_source', {submission: submission.submitid, rank: filePair.1.rank}) }}">
+                    <a class="edit btn btn-secondary btn-sm"
+                       href="{{ path('jury_submission_edit_source', {submission: submission.submitid, rank: 0}) }}">
                         <i class="fas fa-pencil-alt"></i> Edit
                     </a>
                 {% endif %}
-                <div id="diffselect-{{ diff_id }}" class="btn-group">
+                <div class="btn-group">
                     <a href="#" role="button" class="btn btn-secondary btn-sm pe-none" aria-disabled="true"><i class="fas fa-code-branch"></i></a>
+                    <select class="diff-select btn btn-secondary btn-sm form-select-sm text-start" aria-label="Submission to diff against">
+                        <option value="">No diff</option>
+                        {%- for other in otherSubmissions %}
+                        <option value="{{ other.submitid }}">
+                            {%- if originalSubmission and originalSubmission.submitid == other.submitid %}
+                            s{{ other.submitid }} (original)
+                            {%- elseif oldSubmission and oldSubmission.submitid == other.submitid %}
+                            s{{ other.submitid }} (previous)
+                            {%- else %}
+                            s{{ other.submitid }}
+                            {%- endif %}
+                        </option>
+                        {%- endfor %}
+                    </select>
+                </div>
+                <div class="diff-mode btn-group">
+                    <a href="#" role="button" class="btn btn-secondary btn-sm pe-none" aria-disabled="true"><i class="fas fa-plus-minus"></i></a>
                     {%- for mode_id, mode in diff_modes %}
-                    <input type="radio" class="btn-check" name="{{ diff_id }}-mode" id="{{ diff_id }}-{{ mode_id }}" value="{{ mode_id }}" autocomplete="off">
-                    <label class="btn btn-outline-secondary btn-sm" for="{{ diff_id }}-{{ mode_id }}">{{ mode.name }}</label>
+                    <input type="radio" class="btn-check" name="{{ editor_id }}-mode" id="{{ editor_id }}-{{ mode_id }}" value="{{ mode_id }}" autocomplete="off">
+                    <label class="btn btn-outline-secondary btn-sm" for="{{ editor_id }}-{{ mode_id }}">{{ mode.name }}</label>
                     {%- endfor %}
                 </div>
             </div>
-            {{ showDiff(diff_id, filePair.0, filePair.1) }}
-        </div>
-        {% set extra_css_classes = "" %}
-    {%- endfor %}
-    {%- for file in oldFileStats.unchangedfiles %}
-        <div class="tab-pane fade {{ extra_css_classes }}" id="diff-{{ file.submitfileid }}" role="tabpanel">
-            <div class="mb-1">
-                <a class="btn btn-secondary btn-sm"
-                   href="{{ path('jury_submission_source', {submission: submission.submitid, fetch: file.rank}) }}">
-                    <i class="fas fa-download"></i> Download
-                </a>
-                {% if allowEdit %}
-                    <a class="btn btn-secondary btn-sm"
-                       href="{{ path('jury_submission_edit_source', {submission: submission.submitid, rank: file.rank}) }}">
-                        <i class="fas fa-pencil-alt"></i> Edit
-                    </a>
-                {% endif %}
-            </div>
-            {{ file.sourcecode | codeEditor(file.rank, submission.language.editorLanguage) }}
-        </div>
-        {% set extra_css_classes = "" %}
-    {%- endfor %}
-    {%- for file in oldFileStats.addedfiles %}
-        <div class="tab-pane fade {{ extra_css_classes }}" id="diff-{{ file.submitfileid }}" role="tabpanel">
-            <div class="mb-1">
-                <a class="btn btn-secondary btn-sm"
-                   href="{{ path('jury_submission_source', {submission: submission.submitid, fetch: file.rank}) }}">
-                    <i class="fas fa-download"></i> Download
-                </a>
-                {% if allowEdit %}
-                    <a class="btn btn-secondary btn-sm"
-                       href="{{ path('jury_submission_edit_source', {submission: submission.submitid, rank: file.rank}) }}">
-                        <i class="fas fa-pencil-alt"></i> Edit
-                    </a>
-                {% endif %}
-            </div>
-            {{ file.sourcecode | codeEditor(file.rank, submission.language.editorLanguage) }}
+</ul>
+<script>
+$(() => {
+    require(['vs/editor/editor.main'], () => {
+        initDiffEditor('{{ editor_id }}');
+    });
+});
+</script>
+{% set extra_css_classes = "show active" %}
+<div class="tab-content source-tab">
+    {%- for file in files %}
+        {% set diff_id = "diff" ~ file.submitfileid %}
+        <div class="tab-pane fade {{ extra_css_classes }}" id="{{ diff_id }}-tab" role="tabpanel">
+            {{ showDiff(editor_id, diff_id, file, otherFiles) }}
         </div>
         {% set extra_css_classes = "" %}
     {%- endfor %}
 </div>
+</div>
diff --git a/webapp/templates/jury/submission_source.html.twig b/webapp/templates/jury/submission_source.html.twig
index dba2b6cd92..2cf2b79893 100644
--- a/webapp/templates/jury/submission_source.html.twig
+++ b/webapp/templates/jury/submission_source.html.twig
@@ -37,12 +37,8 @@
         <p><b>Entry point</b>: {{ submission.entryPoint }}</p>
     {%- endif %}
 
-    {%- if submission.originalSubmission %}
-        <p><a href="#origdiff">Go to diff to original submission</a></p>
-    {%- endif %}
-
-    {% if oldSubmission %}
-        {%- include 'jury/partials/submission_diff.html.twig' with {oldSubmission: oldSubmission, oldFileStats: otherFiles[oldSubmission.submitid]} %}
+    {% if otherFiles | length > 0 %}
+        {%- include 'jury/partials/submission_diff.html.twig' with {editor_id: "diffw" ~ submission.submitid} %}
     {% else %}
         <ul class="nav nav-tabs source-tab-nav">
             {%- for file in files %}
@@ -75,16 +71,4 @@
             {%- endfor %}
         </div>
     {% endif %}
-
-    {%- if originalSubmission is not null %}
-        <h2 id="origdiff" class="mt-3">
-            Diff to original submission
-            <a href="{{ path('jury_submission', {submitId: originalSubmission.submitid}) }}">
-                s{{ originalSubmission.submitid }}
-            </a>
-        </h2>
-
-        {%- include 'jury/partials/submission_diff.html.twig' with {oldSubmission: originalSubmission, oldFileStats: otherFiles[originalSubmission.submitid]} %}
-    {%- endif %}
-
 {% endblock %}
\ No newline at end of file

From 09ab6a50bf4daf6c1e0cc96db0a6d32949b47f5f Mon Sep 17 00:00:00 2001
From: Kevin Jilissen <info@kevinjilissen.nl>
Date: Sat, 4 Oct 2025 11:21:44 +0200
Subject: [PATCH 3/4] Store and restore preferred diff tag

---
 webapp/public/js/domjudge.js                  | 57 +++++++++++++++----
 .../jury/partials/submission_diff.html.twig   | 18 +++---
 2 files changed, 54 insertions(+), 21 deletions(-)

diff --git a/webapp/public/js/domjudge.js b/webapp/public/js/domjudge.js
index 05d014cefc..194364f9a9 100644
--- a/webapp/public/js/domjudge.js
+++ b/webapp/public/js/domjudge.js
@@ -138,6 +138,20 @@ function setDiffMode(value)
     localStorage.setItem('domjudge_editor_diff_mode', value);
 }
 
+function getDiffTag()
+{
+    let diffTag = localStorage.getItem('domjudge_editor_diff_tag');
+    if (diffTag === undefined) {
+        return 'no-diff';
+    }
+    return diffTag;
+}
+
+function setDiffTag(value)
+{
+    localStorage.setItem('domjudge_editor_diff_tag', value);
+}
+
 // Send a notification if notifications have been enabled.
 // The options argument is passed to the Notification constructor,
 // except that the following tags (if found) are interpreted and
@@ -1295,10 +1309,23 @@ const editors = [];
 function initDiffEditor(editorId) {
     const wrapper = $(`#${editorId}-wrapper`);
 
-    // TODO: store and restore tag preference in local storage.
-    const initialSelect = "";
+    const initialTag = getDiffTag();
     const select = wrapper.find(".diff-select");
-    select[0].selectedIndex = 0;
+    for (let i = 0; i < select[0].options.length; i++) {
+        if (select[0].options[i].dataset.tag == initialTag) {
+            select[0].selectedIndex = i;
+            break;
+        }
+    }
+    // Fall back to other tagged diff if preferred tag is not available for this submission.
+    if (initialTag !== "no-diff" && select[0].selectedIndex === 0) {
+        for (let i = 1; i < select[0].options.length; i++) {
+            if (select[0].options[i].dataset.tag) {
+                select[0].selectedIndex = i;
+                break;
+            }
+        }
+    }
 
     const initialDiffMode = getDiffMode();
     const radios = wrapper.find(`.diff-mode > input[type='radio']`);
@@ -1368,9 +1395,15 @@ function initDiffEditor(editorId) {
         radios.each((_, radio) => {
             radio.disabled = noDiff;
         });
+
+        const selected = select[0].options[select[0].selectedIndex];
+        if (selected && selected.dataset.tag) {
+            setDiffTag(selected.dataset.tag);
+        }
+
         // TODO: add tab panes for deleted source files.
     };
-    updateSelect("", true);
+    updateSelect(select[0].value, select[0].value === "");
     editor.onDiffSelectChange(updateSelect);
 }
 
@@ -1390,6 +1423,13 @@ function initDiffEditorTab(editorId, diffId, rank, models, modifiedModel) {
         theme: getCurrentEditorTheme(),
     });
 
+    const updateMode = (diffMode) => {
+        diffEditor.updateOptions({
+            renderSideBySide: diffMode === 'side-by-side',
+        });
+    };
+    editors[editorId].onDiffModeChange(updateMode);
+
     const updateSelect = (submitId, noDiff) => {
         if (!noDiff) {
             const model = models[submitId];
@@ -1430,7 +1470,7 @@ function initDiffEditorTab(editorId, diffId, rank, models, modifiedModel) {
         })
     };
     editors[editorId].onDiffSelectChange(updateSelect);
-    updateSelect("", true);
+    updateSelect(editors[editorId].getDiffSelection(), editors[editorId].getDiffSelection() === "");
 
     const updateIcon = () => {
         const noDiff = editors[editorId].getDiffSelection() === "";
@@ -1449,11 +1489,4 @@ function initDiffEditorTab(editorId, diffId, rank, models, modifiedModel) {
         }
     }
     diffEditor.onDidUpdateDiff(updateIcon);
-
-    const updateMode = (diffMode) => {
-        diffEditor.updateOptions({
-            renderSideBySide: diffMode === 'side-by-side',
-        });
-    };
-    editors[editorId].onDiffModeChange(updateMode);
 }
\ No newline at end of file
diff --git a/webapp/templates/jury/partials/submission_diff.html.twig b/webapp/templates/jury/partials/submission_diff.html.twig
index f8c94e13b4..fca382c06e 100644
--- a/webapp/templates/jury/partials/submission_diff.html.twig
+++ b/webapp/templates/jury/partials/submission_diff.html.twig
@@ -24,16 +24,16 @@
                 <div class="btn-group">
                     <a href="#" role="button" class="btn btn-secondary btn-sm pe-none" aria-disabled="true"><i class="fas fa-code-branch"></i></a>
                     <select class="diff-select btn btn-secondary btn-sm form-select-sm text-start" aria-label="Submission to diff against">
-                        <option value="">No diff</option>
+                        <option value="" data-tag="no-diff">No diff</option>
                         {%- for other in otherSubmissions %}
-                        <option value="{{ other.submitid }}">
-                            {%- if originalSubmission and originalSubmission.submitid == other.submitid %}
-                            s{{ other.submitid }} (original)
-                            {%- elseif oldSubmission and oldSubmission.submitid == other.submitid %}
-                            s{{ other.submitid }} (previous)
-                            {%- else %}
-                            s{{ other.submitid }}
-                            {%- endif %}
+                        {%- set tag = "" %}
+                        {%- if originalSubmission and originalSubmission.submitid == other.submitid %}
+                            {%- set tag = "original" %}
+                        {%- elseif oldSubmission and oldSubmission.submitid == other.submitid %}
+                            {%- set tag = "previous" %}
+                        {%- endif %}
+                        <option value="{{ other.submitid }}" {%- if tag %} data-tag="{{ tag }}" {%- endif %}>
+                            s{{ other.submitid }} {%- if tag %} ({{ tag }}) {%- endif %}
                         </option>
                         {%- endfor %}
                     </select>

From 0d929c0010974513bc1282d11285409e36a7f399 Mon Sep 17 00:00:00 2001
From: Kevin Jilissen <info@kevinjilissen.nl>
Date: Sun, 5 Oct 2025 12:42:27 +0200
Subject: [PATCH 4/4] Debug GitHub Actions error

---
 .github/workflows/webstandard.yml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/.github/workflows/webstandard.yml b/.github/workflows/webstandard.yml
index 23e0760cab..3ad55c0492 100644
--- a/.github/workflows/webstandard.yml
+++ b/.github/workflows/webstandard.yml
@@ -54,6 +54,15 @@ jobs:
         run: .github/jobs/baseinstall.sh ${{ matrix.role }}
       - name: Run webstandard tests (W3C, WCAG)
         run: .github/jobs/webstandard.sh ${{ matrix.test }} ${{ matrix.role }}
+      - name: dump the db
+        if: ${{ !cancelled() }}
+        run: mysqldump -uroot -proot --quick --max_allowed_packet=1024M domjudge > /tmp/db.sql
+      - name: Upload database dump for debugging
+        if: ${{ !cancelled() }}
+        uses: actions/upload-artifact@v4
+        with:
+          name: DB-dump
+          path: /tmp/db.sql
       - name: Upload all logs/artifacts
         if: ${{ !cancelled() }}
         uses: actions/upload-artifact@v4