Re: [PATCH] builtin-commit: fix "git add x y && git commit y" committing x, too

> Earlier, builtin commit would implicitly commit also the staged
> changes.
> 
> This patch fixes that.
> 
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
> 
> 	The function reset_index_to_head() could be moved to somewhere
> 	more central and be reused in builtin-reset.c instead of
> 	reset_index_file() later...
> 
>  builtin-add.c     |    1 +
>  builtin-commit.c  |   30 +++++++++++++++++++++++++++++-
>  t/t7500-commit.sh |   10 ++++++++++
>  3 files changed, 40 insertions(+), 1 deletions(-)
> 
> diff --git a/builtin-add.c b/builtin-add.c
> index 77dcde6..017c8f2 100644
> --- a/builtin-add.c
> +++ b/builtin-add.c
> @@ -100,6 +100,7 @@ static void update_callback(struct diff_queue_struct *q,
>  		case DIFF_STATUS_UNMERGED:
>  		case DIFF_STATUS_MODIFIED:
>  		case DIFF_STATUS_TYPE_CHANGED:
> +		case DIFF_STATUS_ADDED:
>  			add_file_to_cache(path, verbose);
>  			break;
>  		case DIFF_STATUS_DELETED:
> diff --git a/builtin-commit.c b/builtin-commit.c
> index 535039c..0dc6e1c 100644
> --- a/builtin-commit.c
> +++ b/builtin-commit.c
> @@ -19,6 +19,7 @@
>  #include "strbuf.h"
>  #include "utf8.h"
>  #include "parse-options.h"
> +#include "unpack-trees.h"
>  
>  static const char * const builtin_commit_usage[] = {
>  	"git-commit [options] [--] <filepattern>...",
> @@ -77,6 +78,31 @@ static struct option builtin_commit_options[] = {
>  	OPT_END()
>  };
>  
> +static int reset_index_to_head(void)
> +{
> +	struct unpack_trees_options opts;
> +	struct tree_desc tree_desc;
> +	struct tree *tree;
> +	unsigned char sha1[20];
> +
> +	/* ignore if it is an initial commit */
> +	if (get_sha1("HEAD", sha1))
> +		return 0;
> +	tree = parse_tree_indirect(sha1);
> +	if (!tree || parse_tree(tree))
> +		return error("Could not get HEAD's tree");
> +	init_tree_desc(&tree_desc, tree->buffer, tree->size);
> +
> +	memset(&opts, 0, sizeof(opts));
> +	opts.index_only = 1;
> +	opts.merge = 1;
> +	opts.head_idx = 1;
> +	opts.fn = oneway_merge;
> +	if (unpack_trees(1, &tree_desc, &opts))
> +		return error("Could not reset temporary index to HEAD");
> +	return 0;
> +}
> +
>  static char *prepare_index(const char **files, const char *prefix)
>  {
>  	int fd;
> @@ -120,12 +146,14 @@ static char *prepare_index(const char **files, const char *prefix)
>  			die("failed to read HEAD tree object");
>  	}
>  
> +	if (reset_index_to_head())
> +		die ("failed to reset temporary index to HEAD");
> +