Use diff_tree_combined_merge() instead of open-coding it.

Signed-off-by: René Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Maintaining an array of hashes is easier using sha1_array than
open-coding it.  This patch also fixes a leak of the SHA1 array
in  diff_tree_combined_merge().

Signed-off-by: René Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

* jl/submodule-status-failure-report:
  diff/status: print submodule path when looking for changes fails

diff and status run "git status --porcelain" inside each populated
submodule to see if it contains changes (unless told not to do so via
config or command line option). When that fails, e.g. due to a corrupt
submodule .git directory, it just prints "git status --porcelain failed"
or "Could not run git status --porcelain" without giving the user a clue
where that happened.

Add '"in submodule %s", path' to these error strings to tell the user
where exactly the problem occurred.

Reported-by: Seth Robertson <in-gitvger@baka.org>
Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

* ab/clang-lints:
  cast variable in call to free() in builtin/diff.c and submodule.c
  apply: get rid of useless x < 0 comparison on a size_t type

Both of these free() calls are freeing a "const unsigned char (*)[20]"
type while free() expects a "void *". This results in the following
warning under clang 2.9:

    builtin/diff.c:185:7: warning: passing 'const unsigned char (*)[20]' to parameter of type 'void *' discards qualifiers
            free(parent);
                 ^~~~~~

    submodule.c:394:7: warning: passing 'const unsigned char (*)[20]' to parameter of type 'void *' discards qualifiers
            free(parents);
                 ^~~~~~~

This free()-ing without a cast was added by Jim Meyering to
builtin/diff.c in v1.7.6-rc3~4 and later by Fredrik Gustafsson in
submodule.c in v1.7.7-rc1~25^2.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

The submodule merge search is not useful during virtual merges because
the results cannot be used automatically.  Furthermore any suggestions
made by the search may apply to commits different than HEAD:sub and
MERGE_HEAD:sub, thus confusing the user.  Skip searching for submodule
merges during a virtual merge such as that between B and C while merging
the heads of:

    B---BC
   / \ /
  A   X
   \ / \
    C---CB

Run the search only when the recursion level is zero (!o->call_depth).
This fixes known breakage tested in t7405-submodule-merge.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

* jk/argv-array:
  run_hook: use argv_array API
  checkout: use argv_array API
  bisect: use argv_array API
  quote: provide sq_dequote_to_argv_array
  refactor argv_array into generic code
  quote.h: fix bogus comment
  add sha1_array API docs

* jk/maint-fetch-submodule-check-fix:
  fetch: avoid quadratic loop checking for updated submodules

The submodule code recently grew generic code to build a
dynamic argv array. Many other parts of the code can reuse
this, too, so let's make it generically available.

There are two enhancements not found in the original code:

  1. We now handle the NULL-termination invariant properly,
     even when no strings have been pushed (before, you
     could have an empty, NULL argv). This was not a problem
     for the submodule code, which always pushed at least
     one argument, but was not sufficiently safe for
     generic code.

  2. There is a formatted variant of the "push" function.
     This is a convenience function which was not needed by
     the submodule code, but will make it easier to port
     other users to the new code.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>