External System Functionality doesn't respect field configurations defined for the project and allows admins to import issues without mapping mandatory customfields.

Issue Summary

External System Functionality doesn't respect field configurations defined for the project and allows admins to import issues without mapping mandatory customfields.

This is reproducible on Data Center: (yes) / (no)
Yes

Steps to Reproduce

1. Create a Software project in Jira.
2. Create 2 customfields (of any type sat text fields) and enable them for the newly created project. You can also use system fields like 'Components', 'Sprints' for this purpose.
3. Goto Project settings --> Fields --> Edit field configurations --> Make these customfields as required and save the changes.
4. Re-index the instance if required (since these are new and not used, not required).
5. Now create few issues using GUI (say 5 numbers).
6. Use JQL to search for issues from this project and get these newly created issue listed.
7. Export them to a .CSV file.
8. Now modify the .CSV file and remove the values for customfields created for validation.
9. Now using 'External System Import' functionality import same .CSV file in the same project where you created issues earlier.
10. Don't map the values for these customfields as part of import field mappings.
11. Click on Begin Import.
12. Note that import finishes without any errors and 5 new issues will be created without values for the required customfields, this is violation of field configuration in place.

Expected Results

Import module should catch the exception for missing 'required' customfields mapping and shouldn't allow the import unless the fields are mapped.

Actual Results

System allows the import to succeed and creates new issues without any errors. The required fields values will be missing which will create conflict in long run if these are not noticed. This is because when user tries to edit issues, this flaw will be caught and keeps users/admins confused on how the issues was created without values.

Secondly we can't identify how the issue was created in Jira (Import/GUI/API/Mail etc) which creates further confusion while trying to identify the root cause for such scenarios.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available. However, admins can take caution to validate the field configs before making issue imports using 'External System Import' functionality.