purge: abort with missing files avoiding problems with name-mangling fs
In a name mangling filesystem (e.g. a case insensitive one)
dirstate.walk() can yield filenames different from the ones
stored in the dirstate. This already confuses the status and
add commands, but with purge this may cause data loss.
To prevent this purge refuses to work if there are missing
files and has a 'force' option if the user knows it is safe.
Even with the force option purge checks if any of the missing
files is still available in the working dir: if so there
may be some problem with the underlying filesystem, so it
unconditionally aborts.
#!/bin/sh
hg init
echo a > a
hg commit -A -ma
echo a >> a
hg commit -mb
echo a >> a
hg commit -mc
hg up 1
echo a >> a
hg commit -md
hg up 1
echo a >> a
hg commit -me
hg up 1
echo % should fail because not at a head
hg merge
hg up
echo % should fail because \> 2 heads
hg merge
echo % should succeed
hg merge 2
hg commit -mm1
echo % should succeed - 2 heads
hg merge
hg commit -mm2
echo % should fail because 1 head
hg merge
true