tests/test-extra-filelog-entry.t

stringutil: emit multiple chunks when pretty printing

This avoids concatenating output inside pprintgen() itself. But
the real reason for this is it will make it easier to add
indentation, as we'll need to account for indentation when emitting
each individual object in a collection.

The verbosity of this code compared to the original is a bit
unfortunate. But I suppose this is the price to pay for having
nice things (streaming and indenting).

We could probably abstract the "print a collection" bits into a
generic function to avoid some duplication. But I'm not
overly inclined to do this.

Differential Revision: https://phab.mercurial-scm.org/D4398

Issue351: mq: qrefresh can create extra revlog entry

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init
  $ hg qinit

  $ echo b > b
  $ hg ci -A -m foo
  adding b

  $ echo cc > b
  $ hg qnew -f foo.diff
  $ echo b > b
  $ hg qrefresh

  $ hg debugindex b
     rev linkrev nodeid       p1           p2
       0       0 1e88685f5dde 000000000000 000000000000