Test how largefiles abort in case the disk runs full

  $ cat > criple.py <<EOF

  > import os, errno, shutil

  > from mercurial import util

  > #

  > # this makes the original largefiles code abort:

  > def copyfileobj(fsrc, fdst, length=16*1024):

  >     fdst.write(fsrc.read(4))

  >     raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))

  > shutil.copyfileobj = copyfileobj

  > #

  > # this makes the rewritten code abort:

  > def filechunkiter(f, size=65536, limit=None):

  >     yield f.read(4)

  >     raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))

  > util.filechunkiter = filechunkiter

  > EOF

  $ echo "[extensions]" >> $HGRCPATH

  $ echo "largefiles =" >> $HGRCPATH

  $ hg init alice

  $ cd alice

  $ echo "this is a very big file" > big

  $ hg add --large big

  $ hg commit --config extensions.criple=$TESTTMP/criple.py -m big

  abort: No space left on device

  [255]

The largefile is not created in .hg/largefiles:

  $ ls .hg/largefiles

  dirstate

The user cache is not even created:

  >>> import os; os.path.exists("$HOME/.cache/largefiles/")

  False