there seem to be various different bugs in the zip upload for multiple feedback files, mostly related to having "Download submissions in folders" unchecked:

• Feedback files in the root directory (with prefix, Group1_1_assignsubmission_file_file.txt) are not compared against the original submission files  (seems to be caused by a missing '/' in the truncated file name)
• A feedback file with prefix and missing fifth component (original filename), will cause a coding error.
• Updating a feedback file named for example Group1_1_assignsubmission_file_directory/file.txt will cause a DB exception.

Also, if there are different files evaluating to the same file name (Group1_1_assignsubmission_file_file.txt and Group 1_1_assignsubmission_file_file.txt) both of them are listed and counted in the confirmation dialog, but only one gets added to the feedback. Maybe a warning could be shown in those cases.

For example, creating a zip with following files:

Group 1_1_assignsubmission_file

Group 1_1_assignsubmission_file_

Group1_1_assignsubmission_file_file.txt

Group1_1_assignsubmission_file/file.txt

Group 1_1_assignsubmission_file/file.txt

Group1_1_assignsubmission_file_dir/file.txt

Group1_1_assignsubmission_file/dir/file.txt

results in the following confirmation output:

Warning: Undefined array key "dirname" in /var/www/public/moodle402/mod/assign/feedback/file/importzipform.php on line 98

Warning: Undefined array key "dirname" in /var/www/public/moodle402/mod/assign/feedback/file/importzipform.php on line 98

New feedback file "" for student(s) "Student Eins, Student Zwei"

New feedback file "" for student(s) "Student Eins, Student Zwei"

New feedback file "file.txt" for student(s) "Student Eins, Student Zwei"

New feedback file "/file.txt" for student(s) "Student Eins, Student Zwei"

New feedback file "/file.txt" for student(s) "Student Eins, Student Zwei"

New feedback file "/dir/file.txt" for student(s) "Student Eins, Student Zwei"

New feedback file "dir/file.txt" for student(s) "Student Eins, Student Zwei"

Continuing with the import will cause an error, and of course, only one each of "file.txt" and "dir/file.txt" could even be added as feedback files.