tests/test-issue619

extensions: recommend against using wrapfunction for repo methods

Instead, all extensions should use the "dynamic subclass" trick:
subclass repo.__class__ and then replace repo.__class__ with your new
subclass.  This avoids conflicts that happen when one extension uses
wrapfunction and another uses subclassing to extend the same method of
localrepository.

#!/bin/sh

mkdir t
cd t
hg init
echo a > a
hg ci -Ama -d '1000000000 0'
echo b > b
hg branch b
hg ci -Amb -d '1000000000 0'
hg co -C 0

echo fast-forward
hg merge b
hg ci -Ammerge -d '1000000000 0'

echo bogus fast-forward should fail
hg merge b

echo done