CSV import of grades silently fails when malformed row(s) present

Getting some malformed data to test with

1. Create a new course, and enrol a few users in it.
2. Create a new assignment activity with submission types set to online text.
3. As two students, complete the assignment.
4. As a teacher or admin user, grade the students.
5. Go to the course's grader report, by clicking Course administration -> Grades.
6. Navigate to Grade administration -> Export -> Plain text file.
   • Export a CSV file using commas as the separator.
7. Open the CSV file you generated.
   • Observe that the first line is a header row, with names for each data column.
   • Pick a subsequent row and completely excise a column from it - not just the data value, but the comma after it as well.
   • Save your CSV file as malformed.csv.

Testing with malformed data

1. Navigate to Grade administration -> Import -> CSV file.
2. Upload your malformed CSV file, selecting comma as the separator and with a non-zero number of preview rows.
3. Click Upload grades.
   • Observe that an error message is displayed.