Merge branch 'tb/midx-no-bitmap-for-no-objects'

When there is no object to write .bitmap file for, "git
multi-pack-index" triggered an error, instead of just skipping,
which has been corrected.

* tb/midx-no-bitmap-for-no-objects:
  midx: prevent writing a .bitmap without any objects

1 files changed, 9 insertions, 0 deletions

diff --git a/midx.c b/midx.c
index 6e6cb0e..865170b 100644
--- a/midx.c
+++ b/midx.c
@@ -1077,6 +1077,9 @@ static int write_midx_bitmap(char *midx_name, unsigned char *midx_hash,
 	char *bitmap_name = xstrfmt("%s-%s.bitmap", midx_name, hash_to_hex(midx_hash));
 	int ret;
 
+	if (!ctx->entries_nr)
+		BUG("cannot write a bitmap without any objects");
+
 	if (flags & MIDX_WRITE_BITMAP_HASH_CACHE)
 		options |= BITMAP_OPT_HASH_CACHE;
 
@@ -1401,6 +1404,12 @@ static int write_midx_internal(const char *object_dir,
 		goto cleanup;
 	}
 
+	if (!ctx.entries_nr) {
+		if (flags & MIDX_WRITE_BITMAP)
+			warning(_("refusing to write multi-pack .bitmap without any objects"));
+		flags &= ~(MIDX_WRITE_REV_INDEX | MIDX_WRITE_BITMAP);
+	}
+
 	cf = init_chunkfile(f);
 
 	add_chunk(cf, MIDX_CHUNKID_PACKNAMES, pack_name_concat_len,