Note: this is a longstanding issue with a feature that we generally recommend avoiding. At this point, it is not clear when we will fix this (or if we will fix it at all). Filing this mainly to document.

The pkg_filter option for tag inheritance was intended as a way to inherit only part of the contents of a tag. The field contains a regular expression that is matched against package names, and if the field is set only packages that match the filter are inherited along that inheritance line.

Unfortunately, the filter is only applied when generating the package list for the tag. It is not consulted when generating the build list (except indirectly, since the package list for a tag limits the build list).

In some cases, the feature can work. It will work as long as the package(s) in question are not inherited by the tag via any other pathways. In such a case, the package list entry is blocked by the filter and so the tag will not report any builds for it.

Basically, the filter only applies to the package list.

Changing this now is complicated. If we change the behavior of pkg_filter, then we would retroactively change the historical contents of tags that used this feature.

If we opt to fix this in the future, then we should probably add a new filter field that offers the more expected behavior. However, if we do that, we might also want to look into changing the way that package lists and package blocks work, since that is related and also very confusing to users.