However, when the text after the prompt ends before window-width, typing
C-e with point within the prompt still moves to the end of the text,
even with this patch.  I currently don't see a way to confine the
movement to the prompt field in this case without changing line-move-1,
probably the code involving the test (zerop (vertical-motion 1)).  I
could try to do that, but maybe it's better just to retain the current
behavior of move-end-of-line in the minibuffer, but make it consistent
with respect to the length of the text after the prompt, as the first
patch does.

Steve Berman