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The "SvnMergeTheory" page has been changed by JulianFoad: http://wiki.apache.org/subversion/SvnMergeTheory?action=diff&rev1=38&rev2=39 <<TableOfContents(2)>> == Background on 3-way merging == - The following sections assume that the reader understands how the diff3 algorithm works. The diff3 algorithm is used to perform a merge between an original version of a file and two different versions of the file, each derived from the original version (in Subversion, the derived versions are often referred to as "mine" and "theirs"). This paper provides an explanation and an analysis of the diff3 algorithm: http://www.cis.upenn.edu/~bcpierce/papers/diff3-short.pdf == Playing catch-up with Sync and Reintegrate == @@ -65, +64 @@ More significantly, neither does the mergeinfo "B:1-4" accurately describe the set of ''physical changes'' that were merged. The physical (3-way) merge took the difference between A2 and B4, which we can describe as A2:B3 followed by B3:B4. The second part (B3:B4) we can descibe in mergeinfo syntax as "B:4". The first part, A2:B3, we can't describe using mergeinfo syntax. Logically it's equivalent to changes B1 and B2, but it's not physically the same, because A2:B3 is the rewriting of B1 and B2 into the context of branch A. (See [[#The_Two_Sides_of_a_Merge|The Two Sides of a Merge]], below, for clarification.) == Cherry-pick Merges == + If a cherry-pick merge has occurred since the last complete (sync or reintegrate) merge, the next complete merge should, loosely speaking, skip it. We can classify such a cherry-pick by its position and direction: + + [GRAPH: 3 kinds + the really-a-sync kind] + === Sync with Cherry-Pick in Same Direction === Subversion's ''sync'' merge handles cherry-picks in the same direction by skipping over them, splitting the merge into two or more phases, with each phase performing a 3-way merge of one sub-range of the requested source range.
