Re: [PATCH v4 03/10] update-index: add --test-untracked-cache

> It is nice to just be able to test if untracked cache is
> supported without enabling it.
>
> Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
> ---
>  Documentation/git-update-index.txt | 12 +++++++++++-
>  builtin/update-index.c             |  5 +++++
>  2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
> index f4e5a85..a0afe17 100644
> --- a/Documentation/git-update-index.txt
> +++ b/Documentation/git-update-index.txt
> @@ -18,7 +18,7 @@ SYNOPSIS
>  	     [--[no-]skip-worktree]
>  	     [--ignore-submodules]
>  	     [--[no-]split-index]
> -	     [--[no-|force-]untracked-cache]
> +	     [--[no-|test-|force-]untracked-cache]
>  	     [--really-refresh] [--unresolve] [--again | -g]
>  	     [--info-only] [--index-info]
>  	     [-z] [--stdin] [--index-version <n>]
> @@ -180,6 +180,16 @@ may not support it yet.
>  	system must change `st_mtime` field of a directory if files
>  	are added or deleted in that directory.
>  
> +--test-untracked-cache::
> +	Only perform tests on the working directory to make sure
> +	untracked cache can be used. You have to manually enable
> +	untracked cache using `--force-untracked-cache` (or
> +	`--untracked-cache` but this will run the tests again)
> +	afterwards if you really want to use it. If a test fails
> +	the exit code is 1 and a message explains what is not
> +	working as needed, otherwise the exit code is 0 and OK is
> +	printed.
> +

>  --force-untracked-cache::
>  	For safety, `--untracked-cache` performs tests on the working
>  	directory to make sure untracked cache can be used. These
> diff --git a/builtin/update-index.c b/builtin/update-index.c
> index 1e546a3..62222dd 100644
> --- a/builtin/update-index.c
> +++ b/builtin/update-index.c
> @@ -40,6 +40,7 @@ enum uc_mode {
>  	UC_UNSPECIFIED = -1,
>  	UC_DISABLE = 0,
>  	UC_ENABLE,
> +	UC_TEST,
>  	UC_FORCE
>  };
>  
> @@ -1004,6 +1005,8 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
>  			N_("enable or disable split index")),
>  		OPT_BOOL(0, "untracked-cache", &untracked_cache,
>  			N_("enable/disable untracked cache")),
> +		OPT_SET_INT(0, "test-untracked-cache", &untracked_cache,
> +			    N_("test if the filesystem supports untracked cache"), UC_TEST),
>  		OPT_SET_INT(0, "force-untracked-cache", &untracked_cache,
>  			    N_("enable untracked cache without testing the filesystem"), UC_FORCE),
>  		OPT_END()
> @@ -1119,6 +1122,8 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
>  			setup_work_tree();
>  			if (!test_if_untracked_cache_is_supported())
>  				return 1;
> +			if (untracked_cache == UC_TEST)
> +				return 0;
>  		}
>  		if (!the_index.untracked) {
>  			uc = xcalloc(1, sizeof(*uc));