Subject: [PATCH v3 24/24] midx: clear midx on repack

From: Derrick Stolee <[email-masked]>
Date: Thu, 5 Jul 2018 20:53:21 -0400

If a 'git repack' command replaces existing packfiles, then we must
clear the existing multi-pack-index before moving the packfiles it
references.

Signed-off-by: Derrick Stolee <[email-masked]>
---
 builtin/repack.c |  8 ++++++++
 midx.c           | 12 ++++++++++++
 midx.h           |  1 +
 3 files changed, 21 insertions(+)

diff --git a/builtin/repack.c b/builtin/repack.c
index 6c636e159e..66a7d8e8ea 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -8,6 +8,7 @@
 #include "strbuf.h"
 #include "string-list.h"
 #include "argv-array.h"
+#include "midx.h"
 
 static int delta_base_offset = 1;
 static int pack_kept_objects = -1;
@@ -174,6 +175,7 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 	int no_update_server_info = 0;
 	int quiet = 0;
 	int local = 0;
+	int midx_cleared = 0;
 
 	struct option builtin_repack_options[] = {
 		OPT_BIT('a', NULL, &pack_everything,
@@ -340,6 +342,12 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 				continue;
 			}
 
+			if (!midx_cleared) {
+				/* if we move a packfile, it will invalidated the midx */
+				clear_midx_file(get_object_directory());
+				midx_cleared = 1;
+			}
+
 			fname_old = mkpathdup("%s/old-%s%s", packdir,
 						item->string, exts[ext].name);
 			if (file_exists(fname_old))
diff --git a/midx.c b/midx.c
index 7c00b02436..8afd08f3fe 100644
--- a/midx.c
+++ b/midx.c
@@ -903,3 +903,15 @@ int write_midx_file(const char *object_dir)
 	free(midx_name);
 	return 0;
 }
+
+void clear_midx_file(const char *object_dir)
+{
+	char *midx = get_midx_filename(object_dir);
+
+	if (remove_path(midx)) {
+		UNLEAK(midx);
+		die(_("failed to clear multi-pack-index at %s"), midx);
+	}
+
+	free(midx);
+}
diff --git a/midx.h b/midx.h
index 5faffb7bc6..5a42cbed1d 100644
--- a/midx.h
+++ b/midx.h
@@ -15,5 +15,6 @@ int midx_contains_pack(struct multi_pack_index *m, const char *idx_name);
 int prepare_multi_pack_index_one(struct repository *r, const char *object_dir);
 
 int write_midx_file(const char *object_dir);
+void clear_midx_file(const char *object_dir);
 
 #endif
-- 
2.18.0.118.gd4f65b8d14