repack.c: rename and unlink pack file if it exists

When a repo was fully repacked, and is repacked again, we may run
into the situation that "new" packfiles have the same name as
already existing ones (traditionally packfiles have been named after
the list of names of objects in them, so repacking all the objects
in a single pack would have produced a packfile with the same name).

The logic is to rename the existing ones into filename like
"old-XXX", create the new ones and then remove the "old-" ones.
When something went wrong in the middle, this sequence is rolled
back by renaming the "old-" files back.

The renaming into "old-" did not work as intended, because
file_exists() was done on "XXX", not "pack-XXX".  Also when rolling
back the change, the code tried to rename "old-pack-XXX" but the
saved ones are named "old-XXX", so this couldn't have worked.

Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'tb/repack-fix-renames' (early part)

Finishing touches to the "rewrite repack in C" series.

* 'tb/repack-fix-renames' (early part):
  repack.c: rename and unlink pack file if it exists
Merge branch 'nd/transport-positive-depth-only' into maint

"git fetch --depth=0" was a no-op, and was silently ignored.
Diagnose it as an error.

* nd/transport-positive-depth-only:
  clone,fetch: catch non positive --depth option value
Merge branch 'tb/clone-ssh-with-colon-for-port' into maint

Remote repository URL expressed in scp-style host:path notation are
parsed more carefully (e.g. "foo/bar:baz" is local, "[::1]:/~user" asks
to connect to user's home directory on host at address ::1.

* tb/clone-ssh-with-colon-for-port:
  git_connect(): use common return point
  connect.c: refactor url parsing
  git_connect(): refactor the port handling for ssh
  git fetch: support host:/~repo
  t5500: add test cases for diag-url
  git fetch-pack: add --diag-url
  git_connect: factor out discovery of the protocol and its parts
  git_connect: remove artificial limit of a remote command
  t5601: add tests for ssh
  t5601: remove clear_ssh, refactor setup_ssh_wrapper
Merge branch 'tr/send-email-ssl' into maint

SSL-related options were not passed correctly to underlying socket
layer in "git send-email".

* tr/send-email-ssl:
  send-email: set SSL options through IO::Socket::SSL::set_client_defaults
  send-email: --smtp-ssl-cert-path takes an argument
  send-email: pass Debug to Net::SMTP::SSL::new
Merge branch 'jl/commit-v-strip-marker' into maint

"git commit -v" appends the patch to the log message before
editing, and then removes the patch when the editor returned
control. However, the patch was not stripped correctly when the
first modified path was a submodule.

* jl/commit-v-strip-marker:
  commit -v: strip diffs and submodule shortlogs from the commit message
Merge branch 'jh/rlimit-nofile-fallback' into maint

When we figure out how many file descriptors to allocate for
keeping packfiles open, a system with non-working getrlimit() could
cause us to die(), but because we make this call only to get a
rough estimate of how many is available and we do not even attempt
to use up all file descriptors available ourselves, it is nicer to
fall back to a reasonable low value rather than dying.

* jh/rlimit-nofile-fallback:
  get_max_fd_limit(): fall back to OPEN_MAX upon getrlimit/sysconf failure
Merge branch 'bc/log-decoration' into maint

"git log --decorate" did not handle a tag pointed by another tag
nicely.

* bc/log-decoration:
  log: properly handle decorations with chained tags
Merge branch 'nd/add-empty-fix' into maint

"git add -A" (no other arguments) in a totally empty working tree
used to emit an error.

* nd/add-empty-fix:
  add: don't complain when adding empty project root
Merge branch 'js/lift-parent-count-limit' into maint

There is no reason to have a hardcoded upper limit of the number of
parents for an octopus merge, created via the graft mechanism, but
there was.

* js/lift-parent-count-limit:
  Remove the line length limit for graft files
Merge branch 'ow/stash-with-ifs' into maint

The implementation of 'git stash $cmd "stash@{...}"' did not quote
the stash argument properly and left it split at IFS whitespace.

* ow/stash-with-ifs:
  stash: handle specifying stashes with $IFS
Merge branch 'jc/maint-pull-docfix' into maint

The documentation to "git pull" hinted there is an "-m" option
because it incorrectly shared the documentation with "git merge".

* jc/maint-pull-docfix:
  Documentation: "git pull" does not have the "-m" option
  Documentation: exclude irrelevant options from "git pull"
Git 1.8.5.4

Signed-off-by: Junio C Hamano <gitster@pobox.com>
howto/maintain-git.txt: new version numbering scheme

We wanted to call the upcoming release "Git 1.9", with its
maintenance track being "Git 1.9.1", "Git 1.9.2", etc., but various
third-party tools are reported to assume that there are at least
three dewey-decimal components in our version number.

Adjust the plan so that vX.Y.0 are feature releases while vX.Y.Z
(Z > 0) are maintenance releases.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Sync with 1.8.5.4