fetch-pack: prepare updated shallow file before fetching the pack

index-pack --strict looks up and follows parent commits. If shallow
information is not ready by the time index-pack is run, index-pack may
be led to non-existent objects. Make fetch-pack save shallow file to
disk before invoking index-pack.

git learns new global option --shallow-file to pass on the alternate
shallow file path. Undocumented (and not even support --shallow-file=
syntax) because it's unlikely to be used again elsewhere.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/git.c b/git.c
index 1ada169..88eef5a 100644
--- a/git.c
+++ b/git.c
@@ -4,6 +4,7 @@
 #include "help.h"
 #include "quote.h"
 #include "run-command.h"
+#include "commit.h"
 
 const char git_usage_string[] =
 	"git [--version] [--help] [-c name=value]\n"
@@ -146,6 +147,12 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 			setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 			if (envchanged)
 				*envchanged = 1;
+		} else if (!strcmp(cmd, "--shallow-file")) {
+			(*argv)++;
+			(*argc)--;
+			set_alternate_shallow_file((*argv)[0]);
+			if (envchanged)
+				*envchanged = 1;
 		} else {
 			fprintf(stderr, "Unknown option: %s\n", cmd);
 			usage(git_usage_string);