Instead of implicitly relying on the global 'the_index', convert
'get_next_submodule()' to use the index of the repository stored in the
callback data 'struct submodule_parallel_fetch'.

Since this removes the last user of the index compatibility macros,
define 'NO_THE_INDEX_COMPATIBILITY_MACROS' to prevent future users of
these macros in submodule.c.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Commit 883e248b8 (fsmonitor: teach git to optionally utilize a file
system monitor to speed up detecting new or changed files., 2017-09-22)
introduced a call to 'ce_match_stat()' in 'is_staging_gitmodules_ok()'
which implicitly relys on the the global 'the_index' instead of the
passed in 'struct index_state'.  Fix this by changing the call to
'ie_match_stat()' and using the passed in index_state struct.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

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

The ssh-variant 'simple' introduced earlier broke existing
installations by not passing --port/-4/-6 and not diagnosing an
attempt to pass these as an error.  Instead, default to
automatically detect how compatible the GIT_SSH/GIT_SSH_COMMAND is
to OpenSSH convention and then error out an invocation to make it
easier to diagnose connection errors.

* jn/ssh-wrappers:
  connect: correct style of C-style comment
  ssh: 'simple' variant does not support --port
  ssh: 'simple' variant does not support -4/-6
  ssh: 'auto' variant to select between 'ssh' and 'simple'
  connect: split ssh option computation to its own function
  connect: split ssh command line options into separate function
  connect: split git:// setup into a separate function
  connect: move no_fork fallback to git_tcp_connect
  ssh test: make copy_ssh_wrapper_as clean up after itself

A new mechanism to upgrade the wire protocol in place is proposed
and demonstrated that it works with the older versions of Git
without harming them.

* bw/protocol-v1:
  Documentation: document Extra Parameters
  ssh: introduce a 'simple' ssh variant
  i5700: add interop test for protocol transition
  http: tell server that the client understands v1
  connect: tell server that the client understands v1
  connect: teach client to recognize v1 server response
  upload-pack, receive-pack: introduce protocol version 1
  daemon: recognize hidden request arguments
  protocol: introduce protocol extension mechanisms
  pkt-line: add packet_write function
  connect: in ref advertisement, shallows are last

Doc update.

* sp/doc-info-attributes:
  doc: Mention info/attributes in gitrepository-layout

In addition to "git stash -m message", the command learned to
accept "git stash -mmessage" form.

* ph/stash-save-m-option-fix:
  stash: learn to parse -m/--message like commit does

Internaly we use 0{40} as a placeholder object name to signal the
codepath that there is no such object (e.g. the fast-forward check
while "git fetch" stores a new remote-tracking ref says "we know
there is no 'old' thing pointed at by the ref, as we are creating
it anew" by passing 0{40} for the 'old' side), and expect that a
codepath to locate an in-core object to return NULL as a sign that
the object does not exist.  A look-up for an object that does not
exist however is quite costly with a repository with large number
of packfiles.  This access pattern has been optimized.

* jk/fewer-pack-rescan:
  sha1_file: fast-path null sha1 as a missing object
  everything_local: use "quick" object existence check
  p5551: add a script to test fetch pack-dir rescans
  t/perf/lib-pack: use fast-import checkpoint to create packs
  p5550: factor out nonsense-pack creation