tests/test-largefiles-small-disk.t

releasenotes: add similarity check function to compare incoming notes

It is possible that the incoming note fragments have some similar content as the
existing release notes. In case of a bug fix, we match for issueNNNN in the
existing notes. For other general cases, it makes use of fuzzywuzzy library to get
a similarity score. If the score is above a certain threshold, we ignore the
fragment, otherwise add it. But the score might be misleading for small commit
messages. So, it uses similarity function only if the length of string (in words)
is above a certain value. The patch adds tests related to its usage. But it needs
improvement in the sense of combining incoming notes. We can use interactive mode
for adding notes. Maybe we can do this if similarity is under a certain range.

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:
  > _origcopyfileobj = shutil.copyfileobj
  > def copyfileobj(fsrc, fdst, length=16*1024):
  >     # allow journal files (used by transaction) to be written
  >     if 'journal.' in fdst.name:
  >         return _origcopyfileobj(fsrc, fdst, length)
  >     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=131072, limit=None):
  >     yield f.read(4)
  >     raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))
  > util.filechunkiter = filechunkiter
  > #
  > def oslink(src, dest):
  >     raise OSError("no hardlinks, try copying instead")
  > util.oslink = oslink
  > 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

Make the commit with space on the device:

  $ hg commit -m big

Now make a clone with a full disk, and make sure lfutil.link function
makes copies instead of hardlinks:

  $ cd ..
  $ hg --config extensions.criple=$TESTTMP/criple.py clone --pull alice bob
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch default
  getting changed largefiles
  abort: No space left on device
  [255]

The largefile is not created in .hg/largefiles:

  $ ls bob/.hg/largefiles
  dirstate