gistfile1.txt

Notational tricks:

 * iff a merger has mergers as both children, break them up with a newline
 * use L/R for "left" and "right" repo
 * use capital letters for the hunk patches
 * normalise m(R L) to m(L R)
 * normalise m(m(...) X) to m(X m(...))
 * normalise m(m(R..) m(L..)) to m(m(L..) m(R..))
 * normalise m(.. t) to m(t ..)
 * save repeated trees as tN

And the patch series...

R1
R2
t0 = m(L1 R1)
t1 = m(t0 R2)
t2 = m(t1 m(L2 t0))
t3 = m(t2 m(L3 m(L2 t0)))
t4 = m(t3 m(L4 m(L3 m(L2 t0))))

nesting.sh

#!/bin/bash

rm -rf example-1 example-2
mkdir example-1
mkdir example-2

darcs init --repo example-1/common --hashed
darcs init --repo example-2/common --darcs

for r in 1 2; do
  cd example-$r

  cd common
    touch f
    darcs record -a -lm "example-$r 0 " -A me --ignore-times
  cd ..

  darcs get common branch-x
  cd branch-x
     for i in 1 2 3 4; do
       echo x$i > f
       darcs record -a -lm "example-$r x $i" -A me --ignore-times
     done
  cd ..

  darcs get common branch-y
  cd branch-y
    for i in 1 2; do
      echo y$i > f
      darcs record -a -lm "example-$r y $i" -A me --ignore-times
    done
    darcs pull ../branch-x -a
  cd ..

  cd ..
done