fix: submit_problem saving history before submission guards

xmodule/capa_block.py

@@ -1752,7 +1752,6 @@ def submit_problem(  # pylint: disable=too-many-statements,too-many-branches,too
         self.lcp.has_saved_answers = False
         answers = self.make_dict_of_responses(data)
         answers_without_files = convert_files_to_filenames(answers)
-        self.student_answers_history.append(answers_without_files)
         event_info["answers"] = answers_without_files
 
         # Can override current time
@@ -1812,6 +1811,9 @@ def submit_problem(  # pylint: disable=too-many-statements,too-many-branches,too
             # self.lcp.context['attempt'] refers to the attempt number (1-based)
             self.lcp.context["attempt"] = self.attempts + 1
             correct_map = self.lcp.grade_answers(answers)
+            # recorded only once grading has succeeded, to stay aligned with the
+            # correct map history that grade_answers appends to
+            self.student_answers_history.append(answers_without_files)
             # self.attempts refers to the number of attempts that did not
             # raise an error (0-based)
             self.attempts = self.attempts + 1

xmodule/tests/test_capa_block.py

@@ -1367,6 +1367,48 @@ def test_submit_problem_error(self):
             # but that this was considered attempt number 2 for grading purposes
             assert block.lcp.context["attempt"] == 2
 
+    def test_submit_problem_error_does_not_record_answer_history(self):
+        """
+        Verify that a submission that fails to grade is not recorded in `student_answers_history`, which keeps it
+        aligned with `correct_map_history`.
+        """
+        exception_classes = [StudentInputError, LoncapaProblemError, ResponseError]
+        for exception_class in exception_classes:
+            block = CapaFactory.create(attempts=1, user_is_staff=False)
+
+            with patch('xblocks_contrib.problem.capa.capa_problem.LoncapaProblem.grade_answers') as mock_grade:
+                mock_grade.side_effect = exception_class('test error')
+
+                get_request_dict = {CapaFactory.input_key(): '3.14'}
+                block.submit_problem(get_request_dict)
+
+            assert not block.student_answers_history, \
+                f"student_answers_history must stay empty when grading raises {exception_class.__name__}"
+            assert len(block.student_answers_history) == len(block.correct_map_history), (
+                "student_answers_history and correct_map_history must stay the same length "
+                f"when grading raises {exception_class.__name__}"
+            )
+
+    def test_answer_and_correct_map_histories_stay_aligned(self):
+        """
+        Verify that `student_answers_history` and `correct_map_history` hold one entry per graded attempt, so
+        an attempt that fails to grade does not misalign the two lists for the attempts that follow it.
+        """
+        block = CapaFactory.create(attempts=0, max_attempts=3, rerandomize=RANDOMIZATION.NEVER)
+
+        block.submit_problem({CapaFactory.input_key(): '3.14'})
+
+        with patch('xblocks_contrib.problem.capa.capa_problem.LoncapaProblem.grade_answers') as mock_grade:
+            mock_grade.side_effect = StudentInputError('test error')
+            block.submit_problem({CapaFactory.input_key(): 'not a number'})
+
+        block.submit_problem({CapaFactory.input_key(): '3.21'})
+
+        assert len(block.student_answers_history) == len(block.correct_map_history) == 2, \
+            "both histories must hold one entry per graded attempt, excluding the attempt that failed to grade"
+        assert block.student_answers_history[-1] == {CapaFactory.answer_key(): '3.21'}, \
+            "the last entry of student_answers_history must be the answers of the last graded attempt"
+
     def test_submit_problem_error_with_codejail_exception(self):
         """Verify codejail execution errors are sanitized and handled correctly."""
 

xmodule/tests/test_delay_between_attempts.py

@@ -198,6 +198,26 @@
         # Also, the number of attempts should not be incremented
         self.assertRegex(result['success'], r"You must wait at least 3 minutes between submissions. 2 minutes remaining\..*")  # pylint: disable=line-too-long  # noqa: PT009
         assert block.attempts == num_attempts
+        assert not block.student_answers_history, \
+            "student_answers_history must stay empty when a submission arrives before the wait period elapsed"
+
+    def test_no_answer_history_when_submitted_too_soon(self):
+        """
+        Verify that a submission rejected for arriving before the wait period
+        elapsed is not recorded in `student_answers_history`.
+        """
+        num_attempts = 1
+        (block, result) = self.create_and_check(
+            num_attempts=num_attempts,
+            last_submission_time=datetime.datetime(2013, 12, 6, 0, 17, 36, tzinfo=UTC),
+            submission_wait_seconds=180,
+            considered_now=datetime.datetime(2013, 12, 6, 0, 18, 36, tzinfo=UTC)
+        )
+        self.assertRegex(result['success'], r"You must wait at least.*")
+        assert block.attempts == num_attempts, \
+            "attempts must not change when a submission arrives before the wait period elapsed"
+        assert block.student_answers_history == [], \
+            "student_answers_history must stay empty when a submission arrives before the wait period elapsed"
 
     def test_submit_quiz_1_second_too_soon(self):
         # Already attempted once (just now)