--- a/hgext/rebase.py Tue Oct 29 21:54:49 2013 +0200
+++ b/hgext/rebase.py Wed Oct 30 19:45:14 2013 +0100
@@ -447,9 +447,44 @@
repo.ui.debug(" already in target\n")
repo.dirstate.write()
repo.ui.debug(" merge against %d:%s\n" % (repo[rev].rev(), repo[rev]))
- base = None
- if repo[rev].rev() != repo[min(state)].rev():
+ if repo[rev].rev() == repo[min(state)].rev():
+ # Case (1) initial changeset of a non-detaching rebase.
+ # Let the merge mechanism find the base itself.
+ base = None
+ elif not repo[rev].p2():
+ # Case (2) detaching the node with a single parent, use this parent
base = repo[rev].p1().node()
+ else:
+ # In case of merge, we need to pick the right parent as merge base.
+ #
+ # Imagine we have:
+ # - M: currently rebase revision in this step
+ # - A: one parent of M
+ # - B: second parent of M
+ # - D: destination of this merge step (p1 var)
+ #
+ # If we are rebasing on D, D is the successors of A or B. The right
+ # merge base is the one D succeed to. We pretend it is B for the rest
+ # of this comment
+ #
+ # If we pick B as the base, the merge involves:
+ # - changes from B to M (actual changeset payload)
+ # - changes from B to D (induced by rebase) as D is a rebased
+ # version of B)
+ # Which exactly represent the rebase operation.
+ #
+ # If we pick the A as the base, the merge involves
+ # - changes from A to M (actual changeset payload)
+ # - changes from A to D (with include changes between unrelated A and B
+ # plus changes induced by rebase)
+ # Which does not represent anything sensible and creates a lot of
+ # conflicts.
+ for p in repo[rev].parents():
+ if state.get(p.rev()) == repo[p1].rev():
+ base = p.node()
+ break
+ if base is not None:
+ repo.ui.debug(" detach base %d:%s\n" % (repo[base].rev(), repo[base]))
# When collapsing in-place, the parent is the common ancestor, we
# have to allow merging with it.
return merge.update(repo, rev, True, True, False, base, collapse)