branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
#require docutils
#require gettext
Test document extraction
$ HGENCODING=UTF-8
$ export HGENCODING
$ { echo C; ls "$TESTDIR/../i18n"/*.po | sort; } | while read PO; do
> LOCALE=`basename "$PO" .po`
> echo "% extracting documentation from $LOCALE"
> LANGUAGE=$LOCALE "$PYTHON" "$TESTDIR/../doc/gendoc.py" >> gendoc-$LOCALE.txt 2> /dev/null || exit
>
> if [ $LOCALE != C ]; then
> if [ ! -f $TESTDIR/test-gendoc-$LOCALE.t ]; then
> echo missing test-gendoc-$LOCALE.t
> fi
> cmp -s gendoc-C.txt gendoc-$LOCALE.txt && echo "** NOTHING TRANSLATED ($LOCALE) **"
> fi
> done; true
% extracting documentation from C
% extracting documentation from da
% extracting documentation from de
% extracting documentation from el
% extracting documentation from fr
% extracting documentation from it
% extracting documentation from ja
% extracting documentation from pt_BR
% extracting documentation from ro
% extracting documentation from ru
% extracting documentation from sv
% extracting documentation from zh_CN
% extracting documentation from zh_TW