Lateral rebase operations
A lateral rebase operation occurs when the baseline to which the stream rebases and the baseline in the stream being rebased have no relationship to each other or if the relationship between the baselines is too distant for merging. For example, rebasing to an imported baseline is usually a lateral rebase operation, except when the imported baseline is the ancestor of the current baseline. (This condition makes a revert rebase operation.) Imported baselines have no predecessors; therefore, they are related only to their descendant baselines.
A lateral rebase operation is typically used in a project that has vendor software, for example, a set of compilers or other tools. The project does no development on these tools, but it frequently receives a new release of the tools. The new release is added to source control in a VOB, certified, and, if it passes, labeled. The label is then imported into a baseline; rebasing to this imported baseline is a lateral rebase operation.