tests/test-gendoc.t

obsolete: order of magnitude speedup in _computebumpedset

Reminder: a changeset is said "bumped" if it tries to obsolete a immutable
          changeset.


The previous algorithm for computing bumped changeset was:

    1) Get all public changesets
    2) Find all they successors
    3) Search for stuff that are eligible for being "bumped"
       (mutable and non obsolete)

The entry size of this algorithm is `O(len(public))` which is mostly the same as
`O(len(repo))`. Even this this approach mean fewer obsolescence marker are
traveled, this is not very scalable.

The new algorithm is:

    1) For each potential bumped changesets (non obsolete mutable)
    2) iterate over precursors
    3) if a precursors is public. changeset is bumped

We travel more obsolescence marker, but the entry size is much smaller since
the amount of potential bumped should remains mostly stable with time `O(1)`.

On some confidential gigantic repo this move bumped computation from 15.19s to
0.46s (×33 speedup…). On "smaller" repo (mercurial, cubicweb's review) no
significant gain were seen. The additional traversal of obsolescence marker is
probably probably counter balance the advantage of it.

Other optimisation could be done in the future (eg: sharing precursors cache
for divergence detection)

Test document extraction

  $ "$TESTDIR/hghave" docutils || exit 80
  $ HGENCODING=UTF-8
  $ export HGENCODING
  $ { echo C; find "$TESTDIR/../i18n" -name "*.po" | sort; } | while read PO; do
  >     LOCALE=`basename "$PO" .po`
  >     echo
  >     echo "% extracting documentation from $LOCALE"
  >     echo ".. -*- coding: utf-8 -*-" > gendoc-$LOCALE.txt
  >     echo "" >> gendoc-$LOCALE.txt
  >     LANGUAGE=$LOCALE python "$TESTDIR/../doc/gendoc.py" >> gendoc-$LOCALE.txt 2> /dev/null || exit
  > 
  >     if [ $LOCALE != C ]; then
  >         cmp -s gendoc-C.txt gendoc-$LOCALE.txt && echo '** NOTHING TRANSLATED **'
  >     fi
  > 
  >     # We call runrst without adding "--halt warning" to make it report
  >     # all errors instead of stopping on the first one.
  >     echo "checking for parse errors"
  >     python "$TESTDIR/../doc/runrst" html gendoc-$LOCALE.txt /dev/null
  > done
  
  % extracting documentation from C
  checking for parse errors
  
  % extracting documentation from da
  checking for parse errors
  
  % extracting documentation from de
  checking for parse errors
  
  % extracting documentation from el
  checking for parse errors
  
  % extracting documentation from fr
  checking for parse errors
  
  % extracting documentation from it
  checking for parse errors
  
  % extracting documentation from ja
  checking for parse errors
  
  % extracting documentation from pt_BR
  checking for parse errors
  
  % extracting documentation from ro
  checking for parse errors
  
  % extracting documentation from ru
  checking for parse errors
  
  % extracting documentation from sv
  checking for parse errors
  
  % extracting documentation from zh_CN
  checking for parse errors
  
  % extracting documentation from zh_TW
  checking for parse errors