patch 8.0.0636: when reading the undo file fails may use uninitialized data commit https://github.com/vim/vim/commit/56f2db562ddc6c69026d55360f0cfaacd8adc26a Author: Bram Moolenaar <Bram@vim.org> Date: Sun Jun 11 23:09:15 2017 +0200 patch 8.0.0636: when reading the undo file fails may use uninitialized data Problem: When reading the undo file fails may use uninitialized data. Solution: Always clear the buffer on failure.