backfill: add builtin boilerplate

In anticipation of implementing 'git backfill', populate the necessary files
with the boilerplate of a new builtin.

RFC TODO: When preparing this for a full implementation, make sure it is
based on the newest standards introduced by [1].

[1] https://lore.kernel.org/git/xmqqjzfq2f0f.fsf@gitster.g/T/#m606036ea2e75a6d6819d6b5c90e729643b0ff7f7
    [PATCH 1/3] builtin: add a repository parameter for builtin functions

Signed-off-by: Derrick Stolee <stolee@gmail.com>

.gitignore

@@ -19,6 +19,7 @@
 /git-apply
 /git-archimport
 /git-archive
+/git-backfill
 /git-bisect
 /git-blame
 /git-branch

Documentation/git-backfill.txt

@@ -0,0 +1,23 @@
+git-backfill(1)
+===============
+
+NAME
+----
+git-backfill - Download missing objects in a partial clone
+
+
+SYNOPSIS
+--------
+[verse]
+'git backfill' [<options>]
+
+DESCRIPTION
+-----------
+
+SEE ALSO
+--------
+linkgit:git-clone[1].
+
+GIT
+---
+Part of the linkgit:git[1] suite

Makefile

@@ -1211,6 +1211,7 @@ BUILTIN_OBJS += builtin/am.o
 BUILTIN_OBJS += builtin/annotate.o
 BUILTIN_OBJS += builtin/apply.o
 BUILTIN_OBJS += builtin/archive.o
+BUILTIN_OBJS += builtin/backfill.o
 BUILTIN_OBJS += builtin/bisect.o
 BUILTIN_OBJS += builtin/blame.o
 BUILTIN_OBJS += builtin/branch.o

builtin.h

@@ -120,6 +120,7 @@ int cmd_am(int argc, const char **argv, const char *prefix, struct repository *r
 int cmd_annotate(int argc, const char **argv, const char *prefix, struct repository *repo);
 int cmd_apply(int argc, const char **argv, const char *prefix, struct repository *repo);
 int cmd_archive(int argc, const char **argv, const char *prefix, struct repository *repo);
+int cmd_backfill(int argc, const char **argv, const char *prefix, struct repository *repo);
 int cmd_bisect(int argc, const char **argv, const char *prefix, struct repository *repo);
 int cmd_blame(int argc, const char **argv, const char *prefix, struct repository *repo);
 int cmd_branch(int argc, const char **argv, const char *prefix, struct repository *repo);

builtin/backfill.c

@@ -0,0 +1,29 @@
+#include "builtin.h"
+#include "config.h"
+#include "parse-options.h"
+#include "repository.h"
+#include "object.h"
+
+static const char * const builtin_backfill_usage[] = {
+	N_("git backfill [<options>]"),
+	NULL
+};
+
+int cmd_backfill(int argc, const char **argv, const char *prefix, struct repository *repo)
+{
+	struct option options[] = {
+		OPT_END(),
+	};
+
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage_with_options(builtin_backfill_usage, options);
+
+	argc = parse_options(argc, argv, prefix, options, builtin_backfill_usage,
+			     0);
+
+	repo_config(repo, git_default_config, NULL);
+
+	die(_("not implemented"));
+
+	return 0;
+}

command-list.txt

@@ -60,6 +60,7 @@ git-annotate                            ancillaryinterrogators
 git-apply                               plumbingmanipulators            complete
 git-archimport                          foreignscminterface
 git-archive                             mainporcelain
+git-backfill                            mainporcelain           history
 git-bisect                              mainporcelain           info
 git-blame                               ancillaryinterrogators          complete
 git-branch                              mainporcelain           history

git.c

@@ -508,6 +508,7 @@ static struct cmd_struct commands[] = {
 	{ "annotate", cmd_annotate, RUN_SETUP },
 	{ "apply", cmd_apply, RUN_SETUP_GENTLY },
 	{ "archive", cmd_archive, RUN_SETUP_GENTLY },
+	{ "backfill", cmd_backfill, RUN_SETUP },
 	{ "bisect", cmd_bisect, RUN_SETUP },
 	{ "blame", cmd_blame, RUN_SETUP },
 	{ "branch", cmd_branch, RUN_SETUP | DELAY_PAGER_CONFIG },

meson.build

@@ -477,6 +477,7 @@ builtin_sources = [
   'builtin/annotate.c',
   'builtin/apply.c',
   'builtin/archive.c',
+  'builtin/backfill.c',
   'builtin/bisect.c',
   'builtin/blame.c',
   'builtin/branch.c',