Re: [PATCH 3/3] repack: simplify handling of auto-bitmaps and .keep files

> Commit 7328482253 (repack: disable bitmaps-by-default if .keep files
> exist, 2019-06-29) taught repack to prefer disabling bitmaps to
> duplicating objects (unless bitmaps were asked for explicitly).
>
> But there's an easier way to do this: if we keep passing the
> --honor-pack-keep flag to pack-objects when auto-enabling bitmaps, then
> pack-objects already makes the same decision (it will disable bitmaps
> rather than duplicate). Better still, pack-objects can actually decide
> to do so based not just on the presence of a .keep file, but on whether
> that .keep file actually impacts the new pack we're making (so if we're
> racing with a push or fetch, for example, their temporary .keep file
> will not block us from generating bitmaps if they haven't yet updated
> their refs).
>
> And because repack uses the --write-bitmap-index-quiet flag, we don't
> have to worry about pack-objects generating confusing warnings when it
> does see a .keep file. We can confirm this by tweaking the .keep test to
> check repack's stderr.

>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
>  builtin/repack.c  | 17 ++---------------
>  t/t7700-repack.sh |  3 ++-
>  2 files changed, 4 insertions(+), 16 deletions(-)
>
> diff --git a/builtin/repack.c b/builtin/repack.c
> index db93ca3660..632c0c0a79 100644
> --- a/builtin/repack.c
> +++ b/builtin/repack.c
> @@ -89,17 +89,6 @@ static void remove_pack_on_signal(int signo)
>  	raise(signo);
>  }
>  
> -static int has_pack_keep_file(void)
> -{
> -	struct packed_git *p;
> -
> -	for (p = get_all_packs(the_repository); p; p = p->next) {
> -		if (p->pack_keep)
> -			return 1;
> -	}
> -	return 0;
> -}
> -
>  /*
>   * Adds all packs hex strings to the fname list, which do not
>   * have a corresponding .keep file. These packs are not to
> @@ -346,13 +335,11 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
>  
>  	if (write_bitmaps < 0) {
>  		if (!(pack_everything & ALL_INTO_ONE) ||
> -		    !is_bare_repository() ||
> -		    keep_pack_list.nr != 0 ||
> -		    has_pack_keep_file())
> +		    !is_bare_repository())
>  			write_bitmaps = 0;
>  	}
>  	if (pack_kept_objects < 0)
> -		pack_kept_objects = !!write_bitmaps;
> +		pack_kept_objects = write_bitmaps > 0;
>  
>  	if (write_bitmaps && !(pack_everything & ALL_INTO_ONE))
>  		die(_(incremental_bitmap_conflict_error));
> diff --git a/t/t7700-repack.sh b/t/t7700-repack.sh
> index 54f815b8b9..4e855bc21b 100755
> --- a/t/t7700-repack.sh
> +++ b/t/t7700-repack.sh
> @@ -245,7 +245,8 @@ test_expect_success 'no bitmaps created if .keep files present' '
>  	keep=${pack%.pack}.keep &&
>  	test_when_finished "rm -f \"\$keep\"" &&
>  	>"$keep" &&
> -	git -C bare.git repack -ad &&
> +	git -C bare.git repack -ad 2>stderr &&
> +	test_must_be_empty stderr &&
>  	find bare.git/objects/pack/ -type f -name "*.bitmap" >actual &&
>  	test_must_be_empty actual
>  '