Commit 8b0ddd5dd90e1d62f32faf14d5cb4bf88f04a095

Edward Thomson 2015-01-17T23:28:53

merge: lock the index at the start of the merge Always lock the index when we begin the merge, before we write any of the metdata files. This prevents a race where another client may run a commit after we have written the MERGE_HEAD but before we have updated the index, which will produce a merge commit that is treesame to one parent. The merge will finish and update the index and the resultant commit would not be a merge at all.