Stuck shard ranges have been seen in the production, root cause has been
traced back to that s-m-s-r failed to detect parent-child relationship
in overlaps and it either shrinked child shard ranges into parents or
the other way around. A patch has been added to check minimum age before
s-m-s-r performs repair, which will most likely prevent this from
happening again, but we also need to check for parent-child relationship
in overlaps explicitly during repairs. This patch will do that and
remove parent or child shard ranges from doners, and prevent s-m-s-r
from shrinking them into acceptor shard ranges.
Drive-by 1: fixup gap repair probe test.
The probe test is no longer appropriate because we're no longer
allowed to repair parent-child overlaps, so replace the test with a
manually created gap.
Drive-by 2: address probe test TODOs.
The commented assertion would fail because the node filtering
comparison failed to account for the same node having different indexes
when generated for the root versus the shard. Adding a new iterable
function filter_nodes makes the node filtering behave as expected.
Co-Authored-By: Alistair Coles <alistairncoles@gmail.com>
Co-Authored-By: Clay Gerrard <clay.gerrard@gmail.com>
Change-Id: Iaa89e94a2746ba939fb62449e24bdab9666d7bab
a53270a15a