Add a features list to branches.cache to detect caches of old hg versions.
The leading space in the written file makes sure that the feature list never
can match an existing version, even if the first feature can be read as hex.
Additionally old hg versions display the id with --debug, too.
#!/bin/sh
# http://www.selenic.com/mercurial/bts/issue322
echo % file replaced with directory
hg init a
cd a
echo a > a
hg commit -Ama
rm a
mkdir a
echo a > a/a
echo % should fail - would corrupt dirstate
hg add a/a
cd ..
echo % directory replaced with file
hg init c
cd c
mkdir a
echo a > a/a
hg commit -Ama
rm -r a
echo a > a
echo % should fail - would corrupt dirstate
hg add a
cd ..
echo % directory replaced with file
hg init d
cd d
mkdir b
mkdir b/c
echo a > b/c/d
hg commit -Ama
rm -r b
echo a > b
echo % should fail - would corrupt dirstate
hg add b
exit 0