Finding the common ancestor of a file in a merging Change Set
When merging conflicting branches in the Eclipse client the common ancestor of the file is calculated automatically and displayed in the 3-way diff view.
For review purposes it would be helpful to recreate this view. Can the view be restored for completed merges, or can the common ancestor of a merged file be found in the Eclipse Client or via RTC CLI?
One answer
There is no way to open up the Compare editor so that it shows the common ancestor in the top pane after a merge has been completed (i.e after the change set is closed). You can however discover what the merge states were by looking at the file history in the History view. The 'Merges' column will allow you visually track what the previous merge states are, and the common ancestor. There is also a 'Version I'D column so you can easily identify the versions involved. You can also select any 2 rows (file versions) and use the 'Compare' context menu action to bring up a compare editor showing you the diff between those 2 states.
Comments
Unfortunately we have files with rather convoluted histories, so working out the common ancestor is not always easy.
SCM CLI also doesn't provide an interface for accessing the common ancestor?
Alternatively, to implement the calculation myself, how can the predecessors of a merging change set be accessed via the CLI? "show history" will only show a linear history, not branches, right?