Description of problem:
If a bug is both a duplicate of and blocks a bug, you get an error when trying to update the bug.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Visit bug 175951 (which is a duplicate of and blocks 187810)
2. Make a comment on the bug
Error "You can't make a bug block itself or depend on itself."
No error, comment is added.
This was caused by bug 470051, which is trying to copy the blockers to the duplicate bug. You could also possibly cause this error by marking a blocker a duplicate too, or visa versa.
This will be fixed by not copying a blocker to a duplicate if they are the same.
Should be bugzilla‑4.2‑6 hot fix