fix: ensure broken aux file does not kill future pdf generation

app/models/task.rb

@@ -1167,8 +1167,11 @@ def convert_submission_to_pdf(source_folder: FileHelper.student_work_dir(:new),
       begin
         pdf_text = tac.make_pdf
       rescue => e
-        # Try again... with convert to ascic
-        #
+        # Try again...
+        # Without newpax
+        # Ensure latex aux file is removed
+        Dir.glob(Rails.root.join('tmp/rails-latex/**/input.aux')).each { |f| File.delete(f) }
+
         tac2 = TaskAppController.new
         tac2.init(self, true)
 
@@ -1234,6 +1237,9 @@ def convert_submission_to_pdf(source_folder: FileHelper.student_work_dir(:new),
       add_text_comment project.tutor_for(task_definition), "**Automated Comment**: Something went wrong with your submission. Check the files and resubmit this task. #{e.message}"
       raise e
     ensure
+      # Ensure latex aux file is removed - if broken will cause issues for next submission in sidekiq
+      Dir.glob(Rails.root.join('tmp/rails-latex/**/input.aux')).each { |f| File.delete(f) }
+
       clear_in_process
     end
   end

test/models/task_test.rb

@@ -757,6 +757,58 @@ def test_pdf_creation_fails_on_invalid_pdf
     end
   end
 
+  def test_pax_crash_does_not_stop_pdf_creation
+    unit = FactoryBot.create(:unit, student_count: 1, task_count: 0)
+    td = TaskDefinition.new({
+        unit_id: unit.id,
+        tutorial_stream: unit.tutorial_streams.first,
+        name: 'PDF Test Task',
+        description: 'Test task',
+        weighting: 4,
+        target_grade: 0,
+        start_date: unit.start_date + 1.week,
+        target_date: unit.start_date + 2.weeks,
+        abbreviation: 'PDFTestTask',
+        restrict_status_updates: false,
+        upload_requirements: [ { "key" => 'file0', "name" => 'A pdf file', "type" => 'document' } ],
+        plagiarism_warn_pct: 0.8,
+        is_graded: false,
+        max_quality_pts: 0
+      })
+    td.save!
+
+    data_to_post = {
+      trigger: 'ready_for_feedback'
+    }
+
+    # submit an encrypted (but valid) PDF file and ensure it's rejected immediately
+    data_to_post = with_file('test_files/submissions/valid.pdf', 'application/json', data_to_post)
+
+    project = unit.active_projects.first
+
+    add_auth_header_for user: unit.main_convenor_user
+
+    post "/api/projects/#{project.id}/task_def_id/#{td.id}/submission", data_to_post
+
+    assert_equal 201, last_response.status, last_response_body
+
+    task = project.task_for_task_definition(td)
+
+    rails_latex_path = Rails.root.join("tmp/rails-latex/#{Process.pid}-#{Thread.current.hash}")
+    FileUtils.mkdir_p(rails_latex_path)
+    FileUtils.cp(Rails.root.join('test_files/latex/input-broken.aux'), "#{rails_latex_path}/input.aux")
+
+    assert task.convert_submission_to_pdf(log_to_stdout: false)
+    path = task.zip_file_path_for_done_task
+    assert path
+    assert File.exist? path
+    assert File.exist? task.final_pdf_path
+
+    td.destroy
+    assert_not File.exist? path
+    unit.destroy!
+  end
+
   def test_accept_files_checks_they_all_exist
     project = FactoryBot.create(:project)
     unit = project.unit

test_files/latex/input-broken.aux

@@ -0,0 +1,40 @@
+\relax
+\providecommand\hyper@newdestlabel[2]{}
+\providecommand\HyField@AuxAddToFields[1]{}
+\providecommand\HyField@AuxAddToCoFields[2]{}
+\providecommand{\NEWPAX@DestReq}[2]{}
+\providecommand{\NEWPAX@DestProv}[2]{}
+\providecommand\BKM@entry[2]{}
+\NEWPAX@DestProv{000-document.newpax}{Congratulations!}
+\NEWPAX@DestProv{000-document.newpax}{Decision-Tree}
+\NEWPAX@DestProv{000-document.newpax}{Explanation-using-LIME}
+\NEWPAX@DestProv{000-document.newpax}{Feature-importance:}
+\NEWPAX@DestProv{000-document.newpax}{LIME-for-explaining-prediction-images}
+\NEWPAX@DestProv{000-document.newpax}{LIME:}
+\NEWPAX@DestProv{000-document.newpax}{Model-Interpretation-Methods}
+\NEWPAX@DestProv{000-document.newpax}{Model-Performance}
+\NEWPAX@DestProv{000-document.newpax}{Pre-processing}
+\NEWPAX@DestProv{000-document.newpax}{Predictions-on-the-test-data}
+\NEWPAX@DestProv{000-document.newpax}{Split-Train-and-Test-Datasets}
+\NEWPAX@DestProv{000-document.newpax}{Training-the-classification-model}
+\NEWPAX@DestProv{000-document.newpax}{Understanding-the-Census-Income-Dataset}
+\NEWPAX@DestProv{000-document.newpax}{Visualzing-the-Tree}
+\NEWPAX@DestProv{000-document.newpax}{When-a-person's-income-%3C=-$50K}
+\NEWPAX@DestProv{000-document.newpax}{When-a-person's-income-%3E-$50K}
+\NEWPAX@DestProv{000-document.newpax}{When-a-person's-income-actual-is-different-than-predicted}
+\NEWPAX@DestProv{000-document.newpax}{Your-own-test-example}
+\NEWPAX@DestProv{000-document.newpax}{sk-container-id-1}
+\NEWPAX@DestProv{000-document.newpax}{sk-container-id-2}
+\NEWPAX@DestProv{000-document.newpax}{sk-estimator-id-1}
+\NEWPAX@DestProv{000-document.newpax}{sk-estimator-id-2}
+\NEWPAX@DestProv{000-document.newpax}{top_div8WD77G29ZHEFM8A}
+\NEWPAX@DestProv{000-document.newpax}{top_divDR5YA6I6PZOKFNQ}
+\NEWPAX@DestProv{000-document.newpax}{top_divGH11HTIE1SXJUDR}
+\NEWPAX@DestProv{000-document.newpax}{top_divQ4ALLQ5KXQWP33K}
+\NEWPAX@DestProv{000-document.newpax}{top_divR1OKF6JPUWMW89V}
+\NEWPAX@DestProv{000-document.newpax}{top_divSJB1S48PH4T84MA}
+\NEWPAX@DestProv{000-document.newpax}{top_divWA6RJ9LWIJMH2XT}
+\newlabel{LastPage}{{}{27}{}{page.27}{}}
+\gdef\lastpage@lastpage{27}
+\gdef\lastpage@lastpageHy{27}
+\gdef \@abspage@last{28}