This is another attempt on enabling large transactions
(large in terms of open file descriptors). We keep track of how many
lock files are opened by the ref_transaction_commit function.
When more than a reasonable amount of files is open, we close
the file descriptors to make sure the transaction can continue.

Another idea I had during implementing this was to move this file
closing into the lock file API, such that only a certain amount of
lock files can be open at any given point in time and we'd be 'garbage
collecting' open fds when necessary in any relevant call to the lock
file API. This would have brought the advantage of having such
functionality available in other users of the lock file API as well.
The downside however is the over complication, you really need to always
check for (lock->fd != -1) all the time, which may slow down other parts
of the code, which did not ask for such a feature.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Declare it in git_compat_util.h so that other callers can use it.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

The 'lock_fd' is the same as 'lk->fd'. No need to store it twice so remove
it.

No functional changes intended.

Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

During creation of the patch series our discussion we could have a
more descriptive name for the prerequisite for the test so it stays
unique when other limits of ulimit are introduced.

Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Junio C Hamano <gitster@pobox.com>

"diff-highlight" (in contrib/) used to show byte-by-byte
differences, which meant that multi-byte characters can be chopped
in the middle.  It learned to pay attention to character boundaries
(assuming the UTF-8 payload).

* jk/colors:
  diff-highlight: do not split multibyte characters

"git merge --quiet" did not squelch messages from the underlying
merge-recursive strategy.

* jk/merge-quiet:
  merge: pass verbosity flag down to merge-recursive

Documentation update.

* jk/pack-corruption-post-mortem:
  howto: document more tools for recovery corruption

A push into an unborn branch, with "receive.denyCurrentBranch" set
to "updateInstead", did not check out the working tree as expected.

* jc/update-instead-into-void:
  push-to-deploy: allow pushing into an unborn branch and updating it