Dataset is not updated when updating a task

IMPORTANT: This issue is a companion to https://github.com/cms-dev/cms/issues/970. I understand that it is about an old version of CMS, but I am reporting it just because maybe some other users will come across it. I do not expect this to be backported.

Description:

The dataset is not reimported when cmsImportTask -u

Steps to reproduce:

1. Import a task in CMS and attach it to a contest.
2. Modify your reference solution.
3. From the task directory, run cmsMake -c
4. From the task directory, run cmsMake -a
5. From the task directory, run cmsImportTask [-L italy_yaml] -u -c CONTEST_ID .

Expected:

The new version of the dataset (i.e. the input and output files) gets uploaded to the contest.

Actual:

The contest is still using the old version of the dataset.

A workaround is updating the dataset through the admin interface.

Logs

No relevant logs.

System Information

CMS version: 1.3.1
Was CMS installed: yes
Using a virtualenv: no
Postgres version: 9.3.18
Distribution and version: Ubuntu 16.04.4 LTS (xenial)

Start by reproducing the issue with cmsMake -c, cmsMake -a, and cmsImportTask -u -c CONTEST_ID ., using the task and contest setup described. Trace the cmsImportTask update path and compare it with updating the dataset through the admin interface; done means the updated input and output files are uploaded and used by the contest.