Regression analysis - 5.5 (fixed 5.5.1) broken smart group on permissioned relationship
What happened An enhancement was made to CiviCRM to allow relationship permissions to be no/read only/edit instead of just yes/no. This was fixed in the search form but resulted in a breakage in pre-existing smart groups.
How & When was it addressed It was found immediately after 5.5.0 was released (by Noah Miller) and fixed within 24 hours.
How did the regression fit with our processes? The PR had been reviewed by multiple reviewers but this was not something someone thought to test
Recommendations going forwards I think in this case we need to learn from the specific nature of the issue - ie. changes to search forms can affect smart groups and ensure developers are aware of this instance and bear in in mind