remote.c: add command line option parser for "--lockref"

Update "git push" and "git send-pack" to parse this commnd line
option.

The intended sematics is:

 * "--lockref" alone, without specifying the details, will protect
   _all_ remote refs that are going to be updated by requiring their
   current value to be the same as the remote-tracking branch we
   have for them, unless otherwise specified;

 * "--lockref=refname", without specifying the expected value, will
   protect that refname, if it is going to be updated, by requiring
   its current value to be the same as the remote-tracking branch we
   have for it;

 * "--lockref=refname:value" will protect that refname, if it is
   going to be updated, by requiring its current value to be the
   same as the specified value (which is allowed to be different
   from the remote-tracking branch we have for the refname, or we do
   not even have to have such a remote-tracking branch when this
   form is used); and

 * "--no-lockref" will cancel all the previous --lockref on the
   command line.

In any of the forms, when we try to use a remote-tracking branch for
the remote ref being updated, it is an error if there is no such
remote-tracking branch on our end.

Because the command line options are parsed _before_ we know which
remote we are pushing to, there needs further processing to the
parsed data after we instantiate the transport object to:

 * expand "refname" given by the user to a full refname to be
   matched with the list of "struct ref" used in match_push_refs()
   and set_ref_status_for_push(); and

 * learning the actual local ref that is the remote-tracking branch
   for the specified remote ref.

Further, some processing need to be deferred until we find the set
of remote refs and match_push_refs() returns in order to find the
ones that need to be checked after explicit ones have been processed
for "--lockref" (no specific details).

These post-processing will be the topic of the next patch.

Oh, of course, the option name is still not cast in stone.

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

 This round makes --lockref simply a weaker form of --force.

 The old version used to allow "--lockref=<refname>:" to say "I want
 this push to create <refname>, any existing old value should make
 it fail", but the normal fast-forward check already implements it,
 so there is no need for such an option.  This round removes it.

 The old version allowed you to express "I want the old value of
 'master' to be at X and also I want the update to fast-forward" by
 giving only "--lockref=master:X" without "--force".  Because you
 already know if the commit you are updating their 'master' with
 fast-forwards from X or not, such a combination is unnecessary to
 support.  This simplifies the UI greatly, as "--force" can again be
 the big red button that overrides all the safety.

 I think the option now should be renamed to "--force-with-???"; you
 are essentially taking a lease on the ref before you start your
 rebase, and making sure the ref hasn't been updated by other
 people, you are safely forcing your push of a rebased history.

 Perhaps "--force-with-lease"?  "--force-leased-ref"?
push --lockref: implement logic to populate old_sha1_expect[]

This plugs the push_cas_option data collected by the command line
option parser to the transport system with a new function
apply_push_cas(), which is called after match_push_refs() has
already been called.

At this point, we know which remote we are talking to, and what
remote refs we are going to update, so we can fill in the details
that may have been missing from the command line, such as

 (1) what abbreviated refname the user gave us matches the actual
     refname at the remote; and

 (2) which remote tracking branch in our local repository to read the
     value of the object to expect at the remote.

to populate the old_sha1_expect[] field of each of the remote ref.

Still nobody uses this information, which is the topic of the next
patch.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
push --lockref: tie it all together

This teaches the deepest part of the callchain for "git push" (and
"git send-pack") to enforce "the old value of the ref must be this,
otherwise fail this push" (aka "compare-and-swap" / "--lockref").

Signed-off-by: Junio C Hamano <gitster@pobox.com>
t5533: test "push --lockref"

Prepare two repositories, src and dst, the latter of which is a
clone of the former (with tracking branches), and push from the
latter into the former, using --lockref=name (using tracking ref for
"name" when updating "name"), --lockref=name:value, --lockref=name:
(i.e. check creation), and --lockref (using tracking ref for
anything that we update).

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jc/push-cas' into jch

Allow a safer "rewind of the remote tip" push than blind "--force",
by requiring that the overwritten remote ref to be unchanged since
the new history to replace it was prepared.

The machinery is more or less ready, but the interface to override
the safety may need further discussion.

* jc/push-cas:
  t5533: test "push --lockref"
  push --lockref: tie it all together
  push --lockref: implement logic to populate old_sha1_expect[]
  remote.c: add command line option parser for "--lockref"
  builtin/push.c: use OPT_BOOL, not OPT_BOOLEAN
  cache.h: move remote/connect API out of it

# Conflicts:
# 	remote.c
Merge branch 'jk/gcc-function-attributes' into jch

Use the function attributes extension to catch mistakes in use of
our own variadic functions that use NULL sentinel at the end
(i.e. like execl(3)) and format strings (i.e. like printf(3)).

* jk/gcc-function-attributes:
  use "sentinel" function attribute for variadic lists
  add missing "format" function attributes
Merge branch 'nd/const-struct-cache-entry' into jch

* nd/const-struct-cache-entry:
  Convert "struct cache_entry *" to "const ..." wherever possible
Merge branch 'km/svn-1.8-serf-only' into jch

Subversion 1.8.0 that was recently released breaks older subversion
clients coming over http/https in various ways.

* km/svn-1.8-serf-only:
  git-svn: allow git-svn fetching to work using serf
  Git.pm: add new temp_is_locked function
### 2.0
Merge branch 'jc/push-2.0-default-to-simple' into jch

* jc/push-2.0-default-to-simple:
  push: switch default from "matching" to "simple"

# Conflicts:
# 	Documentation/config.txt
# 	Documentation/git-push.txt
# 	builtin/push.c
Merge branch 'jn/add-2.0-u-A-sans-pathspec' into jch

* jn/add-2.0-u-A-sans-pathspec:
  git add: -u/-A now affects the entire working tree
Merge branch 'jc/add-2.0-ignore-removal' into jch

Updated endgame for "git add <pathspec>" that defaults to "--all"
aka "--no-ignore-removal".

* jc/add-2.0-ignore-removal:
  git add <pathspec>... defaults to "-A"

# Conflicts:
# 	builtin/add.c
Merge branch 'jc/core-checkstat-2.0' into jch

* jc/core-checkstat-2.0:
  core.statinfo: remove as promised in Git 2.0
Merge branch 'mg/more-textconv' into pu

Make "git grep" and "git show" pay attention to --textconv when
dealing with blob objects.

I thought this was pretty well designed and executed, but it seems
there are some doubts on the list; kicked back to 'pu'.

* mg/more-textconv:
  grep: honor --textconv for the case rev:path
  grep: allow to use textconv filters
  t7008: demonstrate behavior of grep with textconv
  cat-file: do not die on --textconv without textconv filters
  show: honor --textconv for blobs
  diff_opt: track whether flags have been set explicitly
  t4030: demonstrate behavior of show with textconv

# Conflicts:
# 	object.c
# 	object.h
# 	t/t8007-cat-file-textconv.sh
Merge branch 'jl/submodule-mv' into pu

"git mv A B" when moving a submodule A does "the right thing",
inclusing relocating its working tree and adjusting the paths in
the .gitmodules file.

$gmane/226294

* jl/submodule-mv:
  submodule.c: duplicate real_path's return value
  rm: delete .gitmodules entry of submodules removed from the work tree
  Teach mv to update the path entry in .gitmodules for moved submodules
  Teach mv to move submodules using a gitfile
  Teach mv to move submodules together with their work trees
Merge branch 'jh/shorten-refname' into pu

When remotes/origin/HEAD is not a symbolic ref, "rev-parse
--abbrev-ref remotes/origin/HEAD" ought to show "origin", not
"origin/HEAD", which is fixed with this series (if it is a symbolic
ref that points at remotes/origin/something, then it should show
"origin/something" and it already does).

$gmane/225137

* jh/shorten-refname:
  t1514: refname shortening is done after dereferencing symbolic refs
  shorten_unambiguous_ref(): Fix shortening refs/remotes/origin/HEAD to origin
  t1514: Demonstrate failure to correctly shorten "refs/remotes/origin/HEAD"
  t1514: Add tests of shortening refnames in strict/loose mode

# Conflicts:
# 	refs.c
Merge branch 'jk/gitweb-utf8' into pu

Various fixes to gitweb.

Drew Northup volunteered to take a look into this.
$gmane/226216

* jk/gitweb-utf8:
  gitweb: Fix broken blob action parameters on blob/commitdiff pages
  gitweb: Don't append ';js=(0|1)' to external links
  gitweb: Make feed title valid utf8
  gitweb: Fix utf8 encoding for blob_plain, blobdiff_plain, commitdiff_plain, and patch
Merge branch 'jc/format-patch' into pu

A new option to send a single patch to the standard output to be
appended at the bottom of a message.  I personally have no need for
this, but it was easy enough to cobble together.  Tests, docs and
stripping out more MIMEy stuff are left as exercises to interested
parties.

tying its loose ends.

* jc/format-patch:
  format-patch: --inline-single
  format-patch: rename "no_inline" field

# Conflicts:
# 	log-tree.c
# 	pretty.c
Merge branch 'hv/config-from-blob' into pu

$gmane/223964

* hv/config-from-blob:
  do not die when error in config parsing of buf occurs
  teach config --blob option to parse config from database
  config: make parsing stack struct independent from actual data source
  config: drop cf validity check in get_next_char()
  config: factor out config file stack management
Merge branch 'jc/show-branch' into pu

* jc/show-branch:
  show-branch: use commit slab to represent bitflags of arbitrary width
  show-branch.c: remove "all_mask"
  show-branch.c: abstract out "flags" operation
  show-branch.c: lift all_mask/all_revs to a global static
  show-branch.c: update comment style

# Conflicts:
# 	builtin/show-branch.c