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doc/todo/avoid_unnecessary_union_merges.mdwn

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+Some commands cause a union merge unnecessarily. For example, `git annex add`
+modifies the location log, which first requires reading the current log (if
+any), which triggers a merge.
+
+Would be good to avoid these unnecessary union merges. First because it's
+faster and second because it avoids a possible delay when a user might
+ctrl-c and leave the repo in an inconsistent state. In the case of an add,
+the file will be in the annex, but no location log will exist for it (fsck
+fixes that).
+
+It may be that all that's needed is to modify Annex.Branch.change
+to read the current value, without merging. Then commands like `get`, that
+query the branch, will still cause merges, and commands like `add` that
+only modify it, will not. Note that for a command like `get`, the merge
+occurs before it has done anything, so ctrl-c should not be a problem
+there.
+
+This is a delicate change, I need to take care.. --[[Joey]]