- Note that both conditions below will hold for zero-length (]
- extents at the gap. Zero-length () extents would get adjusted
- such that their start is greater than their end; we treat them
- as [) extents. This is unfortunately an inelegant part of the
- extent model, but there is no way around it. */
+ 1. Start position of start-open extents needs to be moved.
+
+ 2. End position of end-closed extents needs to be moved.
+
+ Note that both conditions hold for zero-length (] extents at the
+ insertion point. But under these rules, zero-length () extents
+ would get adjusted such that their start is greater than their
+ end; instead of allowing that, we treat them as [) extents by
+ modifying condition #1 to not fire nothing when dealing with a
+ zero-length open-open extent.
+
+ Existence of zero-length open-open extents is unfortunately an
+ inelegant part of the extent model, but there is no way around
+ it. */