pack-bitmap.c: avoid exposing absolute paths

In "open_midx_bitmap_1()" and "open_pack_bitmap_1()", when we find that
there are multiple bitmaps, we will only open the first one and then
leave warnings about the remaining pack information, the information
will contain the absolute path of the repository, for example in a
alternates usage scenario. So let's hide this kind of potentially
sensitive information in this commit.

Found-by: XingXin <moweng.xx@antgroup.com>
Signed-off-by: Teng Long <dyroneteng@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>

pack-bitmap.c

@@ -354,8 +354,8 @@ static int open_midx_bitmap_1(struct bitmap_index *bitmap_git,
 	if (bitmap_git->pack || bitmap_git->midx) {
 		struct strbuf buf = STRBUF_INIT;
 		get_midx_filename(&buf, midx->object_dir);
-		/* ignore extra bitmap file; we can only handle one */
-		warning(_("ignoring extra bitmap file: '%s'"), buf.buf);
+		trace2_data_string("bitmap", the_repository,
+				   "ignoring extra midx bitmap file", buf.buf);
 		close(fd);
 		strbuf_release(&buf);
 		return -1;
@@ -429,8 +429,8 @@ static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git
 	}
 
 	if (bitmap_git->pack || bitmap_git->midx) {
-		/* ignore extra bitmap file; we can only handle one */
-		warning(_("ignoring extra bitmap file: '%s'"), packfile->pack_name);
+		trace2_data_string("bitmap", the_repository,
+				   "ignoring extra bitmap file", packfile->pack_name);
 		close(fd);
 		return -1;
 	}
@@ -455,6 +455,8 @@ static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git
 		return -1;
 	}
 
+	trace2_data_string("bitmap", the_repository, "opened bitmap file",
+			   packfile->pack_name);
 	return 0;
 }
 

t/t5310-pack-bitmaps.sh

@@ -428,8 +428,9 @@ test_bitmap_cases () {
 			test_line_count = 2 packs &&
 			test_line_count = 2 bitmaps &&
 
-			git rev-list --use-bitmap-index HEAD 2>err &&
-			grep "ignoring extra bitmap file" err
+			GIT_TRACE2_EVENT=$(pwd)/trace2.txt git rev-list --use-bitmap-index HEAD &&
+			grep "opened bitmap" trace2.txt &&
+			grep "ignoring extra bitmap" trace2.txt
 		)
 	'
 }