pull: implement skeletal builtin pull

For the purpose of rewriting git-pull.sh into a C builtin, implement a
skeletal builtin/pull.c that redirects to $GIT_EXEC_PATH/git-pull.sh if
the environment variable _GIT_USE_BUILTIN_PULL is not defined. This
allows us to fall back on the functional git-pull.sh when running the
test suite for tests that depend on a working git-pull implementation.

This redirection should be removed when all the features of git-pull.sh
have been re-implemented in builtin/pull.c.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/builtin/pull.c b/builtin/pull.c
new file mode 100644
index 000000000..cabeed453
--- /dev/null
+++ b/builtin/pull.c
@@ -0,0 +1,33 @@
+/*
+ * Builtin "git pull"
+ *
+ * Based on git-pull.sh by Junio C Hamano
+ *
+ * Fetch one or more remote refs and merge it/them into the current HEAD.
+ */
+#include "cache.h"
+#include "builtin.h"
+#include "parse-options.h"
+#include "exec_cmd.h"
+
+static const char * const pull_usage[] = {
+	NULL
+};
+
+static struct option pull_options[] = {
+	OPT_END()
+};
+
+int cmd_pull(int argc, const char **argv, const char *prefix)
+{
+	if (!getenv("_GIT_USE_BUILTIN_PULL")) {
+		const char *path = mkpath("%s/git-pull", git_exec_path());
+
+		if (sane_execvp(path, (char **)argv) < 0)
+			die_errno("could not exec %s", path);
+	}
+
+	argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
+
+	return 0;
+}