rust-cpython: rename PyLeakedRef to PyLeaked
This series will make PyLeaked* behave more like a Python iterator, which
means mutation of the owner object will be allowed and the leaked reference
(i.e. the iterator) will be invalidated instead.
I'll add PyLeakedRef/PyLeakedRefMut structs which will represent a "borrowed"
state, and prevent the underlying value from being mutably borrowed while the
leaked reference is in use:
let shared = self.inner_shared(py);
let leaked = shared.leak_immutable();
{
let leaked_ref: PyLeakedRef<_> = leaked.borrow(py);
shared.borrow_mut(); // panics since the underlying value is borrowed
}
shared.borrow_mut(); // allowed
The relation between PyLeaked* structs is quite similar to RefCell/Ref/RefMut,
but the implementation can't be reused because the borrowing state will have
to be shared across objects having no lifetime relation.
PyLeaked isn't named as PyLeakedCell since it isn't actually a cell in that
leaked.borrow_mut() will require &mut self.
$ hg init
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls
a
unknown