log: do not --follow file that is deleted and recreated later (
issue732)
== What ==
issue732 is only one example of a buggy behaviour, but there are in fact many
intricated cases. For example:
( "o" contains an alive version of the tracked file, "x" does not)
tip - o - o - x - o - o - x ...
\
o - o - o - o - x ...
\ /
o - o
This repository contains at least two instances of the tracked file, but
when calling "hg log -f file" only the latest one (the one alive in tip)
matters to us.
== How ==
We must extract from the filelog the history of the file instance we're
interested in and discard changes related to other instances of that file.
We see that we're only interested in ancestors(node), and that all
other nodes in the filelog should not be considered.