While discussing error handling in the experimental FilterParams custom filter editing tool, @kku noted that Gramps discards custom filters that reference non-existent (un-installed add-ons) rules as the custom_filters.xml is loaded. (It’ll take some experimenting to see if this discard is a purge or a quarantine. Perhaps the XML is commented for the affected filters.)
This observation set off alarms.
Add-on rules are a recent feature. There is no option to archive or reload one’s library of Custom Filters. (The text import Gramplet will perform a lot of XML-based object creation, but you cannot paste a custom_filter XML block to create a filter.) If the purge is silent, a LOT of work could be lost with no opportunity for recovery.
Could re-installing a fresh copy of 5.1.x (or migrating to 5.2) destroy many hours of crafting a library of custom filters?
A fresh copy of Gramps will not have the add-on rules packs or SuperTool generic rules installed yet. Meanwhile, Gramps has to run (and load the custom_filters.xml to initialize the active view) so that the Plugin Manager can be used to install the add-ons. Won’t that workflow purge a lot of Custom Filters?
Migrating to 5.2 might not present as much risk. That process will create a gramps52 folder in the Gramps User Directory and the custom filter file would have to be migrated manually.
Come to think of it, un-installing & re-installing a custom filter pack (when suspected of corruption or failed updating) might put custom filters at risk.