I don't know if this is remotely possible unless it's the biggest manually edit I'll ever have to do.
I have 2000+ issues that I basically need to make copies/clones with all of it's custom fields, assignees, linked issues, and tabs filled out exactly the same, except with 3 specific fields that needs to be different.
Example:
Issue Type: Original Bug
Custom Field A
Custom Field B
Custom Field C
Custom Field D
Custom Field E
etc.
x2000 issues. Create 2000+ new issues.
Issue Type: New Bug
Custom Field A (value is the same as Original Bug)
Custom Field B (has a new value)
Custom Field C (has a new value)
Custom Field D (value is the same as Original Bug)
Custom Field E (value is the same as Original Bug)
etc.
It doesn't help also that this issue type has about 50+ custom fields as well each unique with single select list, multi select list, checkboxes, text fields, etc.
I tried exporting the 2000+ issues as csv, but if I want to import, the ones that were selected as multi option fills a new column rather than using (value 1, value 2) separating. I'm looking for an easier way to pull this off and without having to resort to a plugin. I only have Structure and Scriptrunner.