Various valid long-term desireable situations coexist, and while discussing immediate countermeasures, it is useful to keep the long-term outcome that those are most likely to produce.
-These are the five possible situations at the time of bullseye (buster + 1):
+These are the six possible situations at the time of bullseye (buster + 1):
* `none`: "merged `/usr`" has been reverted
+* `empty`: "merged `/usr`" has been reverted, `/usr` is empty (but the mandatory files)
* `weak`: both directory schemes are allowed, packages only built on classical hosts
* `middle`: both directory schemes are allowed, packages can be built anywhere
* `hard`: both directory schemes are allowed, packages only built on "merged `/usr`" hosts
| Codename | classical hosts | merged `/usr` hosts | symlinks allowed | classical hosts | merged `/usr` hosts | classical hosts | merged `/usr` hosts |
|----------|-----------------|---------------------|-------------------|—----------------|---------------------|---------------------|----------------------|
| none | yes | no | no | yes | no | yes | yes |
+| empty | yes | no | no | yes | no | yes | no |
| weak | yes | yes | yes | yes | no | no | yes |
| middle | yes | yes | yes | yes | yes | no | no |
| hard | yes | yes | yes | no | yes | no | no |