[PATCH 2/3] midx: close multi-pack-index on repack

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <dstolee@microsoft.com>

When repacking, we may remove pack-files. This invalidates the
multi-pack-index (if it exists). Previously, we removed the
multi-pack-index file before removing any pack-file. In some cases,
the repack command may load the multi-pack-index into memory. This
may lead to later in-memory references to the non-existent pack-
files.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 builtin/repack.c | 4 ++++
 midx.c           | 6 +++++-
 midx.h           | 2 ++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/builtin/repack.c b/builtin/repack.c
index c6a7943d5c..7925bb976e 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -432,6 +432,10 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 
 			if (!midx_cleared) {
 				/* if we move a packfile, it will invalidated the midx */
+				if (the_repository->objects) {
+					close_midx(the_repository->objects->multi_pack_index);
+					the_repository->objects->multi_pack_index = NULL;
+				}
 				clear_midx_file(get_object_directory());
 				midx_cleared = 1;
 			}
diff --git a/midx.c b/midx.c
index 999717b96f..fe8532a9d1 100644
--- a/midx.c
+++ b/midx.c
@@ -180,9 +180,13 @@ cleanup_fail:
 	return NULL;
 }
 
-static void close_midx(struct multi_pack_index *m)
+void close_midx(struct multi_pack_index *m)
 {
 	uint32_t i;
+
+	if (!m)
+		return;
+
 	munmap((unsigned char *)m->data, m->data_len);
 	close(m->fd);
 	m->fd = -1;
diff --git a/midx.h b/midx.h
index a210f1af2a..af6b5cb58f 100644
--- a/midx.h
+++ b/midx.h
@@ -44,4 +44,6 @@ int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, i
 int write_midx_file(const char *object_dir);
 void clear_midx_file(const char *object_dir);
 
+void close_midx(struct multi_pack_index *m);
+
 #endif
-- 
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