error due to merge

Show errors when conflicts or model inconsistencies are detected when merging. There are two points where the error occurs:

Details of each are shown below.

error when starting merge

An error occurs if there are uncommitted changes in the current branch (own).
- To avoid overwriting uncommitted data, Git detects conflicts and displays errors.

An error will occur if an error is detected during merging.
- In this case, NDMerge aborts the merge process.
There are two main types of errors during merging:
- Edit conflict error
- Error due to model inconsistency
See here for the messages for each error.

An error will occur if a conflict occurs due to edits to individual models.
- Conflict conditions differ depending on the merge target. The conflict conditions for each target are shown below.

Target	Contents
File	File schema version conflict (Note 1)
Entities and relationships	Conflict between field value changes
	Conflict between deleting a model and changing field values in that model
	Collision between deletion of parent model and change of field value in child model
Interaction model	Changes to interaction elements collide (Note 2)
Product line model	Collision in feature model editing
	Feature assignment (feature expression) conflicts
	Conflicting configuration changes
	Constraint conflicts between features
Profile	Conflicting profile changes (Note 3)
Project	Changes to project information (such as overview and category) conflict
	Changes to the setting information on the trace page collide

Note 1 : If there is an update of the schema version held in file units, it will be treated as a conflict.
Note 2 : If there is more than one change in lifelines, messages, etc., it will be treated as a change. In the interaction model (sequence diagram), shape coordinate information is also treated as design data, so changes in coordinates are also subject to conflict.
Note 3 : Profile elements include metamodels, view definitions, resources such as images, and the contents of class diagrams. If there is one or more additions, deletions, or changes regarding them, it is treated as having been changed.

As a result of merging without conflicts, an error will occur if there is an inconsistent state of the model as shown below.
- The ownership association becomes a circular reference
- Multiple parents