tests/test-mq-qimport-fail-cleanup.t

bdiff: fix malloc(0) issue in fixws()

If fixws() is called on a zero-length string, malloc(0) is called and
expected to return a pointer. Which it does on e.g. Linux. AIX returns
NULL, which it is also legal, but the malloc() is then assumed to have
failed. So ensure a valid pointer is always returned.

Failed qimport of patches from files should cleanup by recording successfully
imported patches in series file.

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH
  $ hg init repo
  $ cd repo
  $ echo a > a
  $ hg ci -Am'add a'
  adding a
  $ cat >b.patch<<EOF
  > diff --git a/a b/a
  > --- a/a
  > +++ b/a
  > @@ -1,1 +1,2 @@
  >  a
  > +b
  > EOF

empty series

  $ hg qseries

qimport valid patch followed by invalid patch

  $ hg qimport b.patch fakepatch
  adding b.patch to series file
  abort: unable to read file fakepatch
  [255]

valid patches before fail added to series

  $ hg qseries
  b.patch

  $ hg pull -q -r 0 . # update phase
  [1]
  $ hg qimport -r 0
  abort: revision 0 is not mutable
  (see "hg help phases" for details)
  [255]