A Baseless Merge is a not-that-known feature of the TFS’ Version Control System.
It’s a merge made with two branches of a root with no relationship between them. For instance, two parallel ‘release’ branches.
The suggested way of performing a merge with two branches like those lying around is to reverse integrate the first one into the root and then to remerge inside the other child. But this approach is not always feasible, so you can perform a baseless merge.
It’s a rather risky operation: the Visual Studio ALM Rangers strongly recommend to avoid it, because of the inner troubles inside it: no propagation for deletions, and no auto-solving of conflicts.
Up to Visual Studio ALM 2010, the baseless merge was there! But it was not integrated inside the IDE, and then the only option was to use tf.exe (tf merge /baseless …).
Nowadays we have this feature inside Visual Studio 2012, so no more command line playing.
For instance, in this scenario I’d want to merge Feature1 and Feature2…
…I can do it by calling the Merge Wizard.
It’s explicitly warning me I’m doing something risky: the baseless merge has no relationship with its siblings.
Moreover, if you try to drag and drop from the Hierarchy Viewer, you won’t be able to do a baseless merge. As of its nature, it must be done just purposefully and not ‘by error’.