view mercurial/cext/__init__.py @ 40813:884321cd26c3 stable

rust: fix possible out-of-bounds read through index_get_parents()

index_get_parents() is an internal function, which doesn't check if the
specified rev is valid. If rustlazyancestors() were instantiated with an
invalid stoprev, it would access to invalid memory region.

This is NOT a security fix as there's no Python code triggering the bug,
but included in this series to not give a notion about the memory issue
fixed by the previous patch.