If two units are being compared with a base unit, this
base-aware comparison makes it possible for IBM® Rational® Rhapsody® DiffMerge to
determine automatically the need for some merges using the concept
of trivial versus non-trivial differences.
For more information about this concept, see Trivial versus non-trivial differences.
This three‑unit comparison includes detecting differences
in the model elements, such as new class that was added or removed.
It also locates textual differences in the attribute values of the
model elements, such as change in the class description.
All the differences identified are compared to determine
the trivial versus non‑trivial differences. During an automatic merge
operation, all the trivial differences are automatically accepted
for merging.
Note: Diagrams that have changes on both sides are always considered
as a conflicting difference. Rational Rhapsody DiffMerge always
reports any diagram differences as a conflicting difference, which
you would have to merge manually. For example, if Object Model Diagram
A on the Left side has a new element called Class_1 and
Object Model Diagram B on the Right side has a new element called Class_2,
as shown in the following figure, even though the elements do not
conflict with each other, their individual diagrams are different.
Therefore, during a comparison of Diagram A and Diagram B, Rational Rhapsody DiffMerge would
report that these diagrams have a conflicting difference.