Re: [PATCH v3 1/1] ls-tree.c: support `--oid-only` option for "git-ls-tree"

> Sometimes, we only want to get the objects from output of `ls-tree`
> and commands like `sed` or `cut` is usually used to intercept the
> origin output to achieve this purpose in practical.
> 
> This commit supply an option names `--oid-only` to let `git ls-tree`
> only print out the OID of the object. `--oid-only` and `--name-only`
> are mutually exclusive in use.
> 
> Signed-off-by: Teng Long <dyroneteng@gmail.com>
> ---
>  Documentation/git-ls-tree.txt |  8 +++++--
>  builtin/ls-tree.c             | 27 ++++++++++++++++-------
>  t/t3104-ls-tree-oid.sh        | 40 +++++++++++++++++++++++++++++++++++
>  3 files changed, 65 insertions(+), 10 deletions(-)
>  create mode 100755 t/t3104-ls-tree-oid.sh
> 
> diff --git a/Documentation/git-ls-tree.txt b/Documentation/git-ls-tree.txt
> index db02d6d79a..bc711dc00a 100644
> --- a/Documentation/git-ls-tree.txt
> +++ b/Documentation/git-ls-tree.txt
> @@ -10,7 +10,8 @@ SYNOPSIS
>  --------
>  [verse]
>  'git ls-tree' [-d] [-r] [-t] [-l] [-z]
> -	    [--name-only] [--name-status] [--full-name] [--full-tree] [--abbrev[=<n>]]
> +	    [--name-only] [--name-status] [--oid-only]

> +	    [--full-name] [--full-tree] [--abbrev[=<n>]]
>  	    <tree-ish> [<path>...]
>  
>  DESCRIPTION
> @@ -59,7 +60,10 @@ OPTIONS
>  --name-only::
>  --name-status::
>  	List only filenames (instead of the "long" output), one per line.
> -
> +	Cannot be used with `--oid-only` together.
> +--oid-only::
> +	List only OIDs of the objects, one per line. Cannot be used with
> +	`--name-only` or `--name-status` together.
>  --abbrev[=<n>]::
>  	Instead of showing the full 40-byte hexadecimal object
>  	lines, show the shortest prefix that is at least '<n>'
> diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
> index 3a442631c7..1e4a82e669 100644
> --- a/builtin/ls-tree.c
> +++ b/builtin/ls-tree.c
> @@ -18,19 +18,26 @@ static int line_termination = '\n';
>  #define LS_RECURSIVE 1
>  #define LS_TREE_ONLY 2
>  #define LS_SHOW_TREES 4
> -#define LS_NAME_ONLY 8
> -#define LS_SHOW_SIZE 16
> +#define LS_SHOW_SIZE 8
>  static int abbrev;
>  static int ls_options;
>  static struct pathspec pathspec;
>  static int chomp_prefix;
>  static const char *ls_tree_prefix;
>  
> -static const  char * const ls_tree_usage[] = {
> +static const char * const ls_tree_usage[] = {
>  	N_("git ls-tree [<options>] <tree-ish> [<path>...]"),
>  	NULL
>  };
>  
> +enum {
> +	MODE_UNSPECIFIED = 0,
> +	MODE_NAME_ONLY,
> +	MODE_OID_ONLY
> +};
> +
> +static int cmdmode = MODE_UNSPECIFIED;
> +
>  static int show_recursive(const char *base, int baselen, const char *pathname)
>  {
>  	int i;
> @@ -90,7 +97,12 @@ static int show_tree(const struct object_id *oid, struct strbuf *base,
>  	else if (ls_options & LS_TREE_ONLY)
>  		return 0;
>  
> -	if (!(ls_options & LS_NAME_ONLY)) {
> +	if (cmdmode == 2) {

> +		printf("%s\n", find_unique_abbrev(oid, abbrev));
> +		return 0;
> +	}
> +
> +	if (cmdmode == 0) {

>  		if (ls_options & LS_SHOW_SIZE) {
>  			char size_text[24];
>  			if (!strcmp(type, blob_type)) {
> @@ -135,10 +147,9 @@ int cmd_ls_tree(int argc, const char **argv, const char *prefix)
>  			    N_("terminate entries with NUL byte"), 0),
>  		OPT_BIT('l', "long", &ls_options, N_("include object size"),
>  			LS_SHOW_SIZE),
> -		OPT_BIT(0, "name-only", &ls_options, N_("list only filenames"),
> -			LS_NAME_ONLY),
> -		OPT_BIT(0, "name-status", &ls_options, N_("list only filenames"),
> -			LS_NAME_ONLY),
> +		OPT_CMDMODE('n', "name-only", &cmdmode, N_("list only filenames"), MODE_NAME_ONLY),
> +		OPT_CMDMODE('s', "name-status", &cmdmode, N_("list only filenames"), MODE_NAME_ONLY),
> +		OPT_CMDMODE('o', "oid-only", &cmdmode, N_("list only oids"), MODE_OID_ONLY),
>  		OPT_SET_INT(0, "full-name", &chomp_prefix,
>  			    N_("use full path names"), 0),
>  		OPT_BOOL(0, "full-tree", &full_tree,
> diff --git a/t/t3104-ls-tree-oid.sh b/t/t3104-ls-tree-oid.sh
> new file mode 100755
> index 0000000000..4c02cdd3c3
> --- /dev/null
> +++ b/t/t3104-ls-tree-oid.sh
> @@ -0,0 +1,40 @@
> +#!/bin/sh
> +
> +test_description='git ls-tree oids handling.'
> +
> +. ./test-lib.sh
> +
> +test_expect_success 'setup' '
> +	echo 111 >1.txt &&
> +	echo 222 >2.txt &&
> +	mkdir -p path0/a/b/c &&
> +	echo 333 >path0/a/b/c/3.txt &&
> +	find *.txt path* \( -type f -o -type l \) -print |
> +	xargs git update-index --add &&
> +	tree=$(git write-tree) &&
> +	echo $tree
> +'
> +
> +test_expect_success 'usage: --oid-only' '
> +	git ls-tree --oid-only $tree >current &&
> +	git ls-tree $tree | awk "{print \$3}" >expected &&
> +	test_cmp current expected
> +'
> +
> +test_expect_success 'usage: --oid-only with -r' '
> +	git ls-tree --oid-only -r $tree >current &&
> +	git ls-tree -r $tree | awk "{print \$3}" >expected &&
> +	test_cmp current expected
> +'
> +
> +test_expect_success 'usage: --oid-only with --abbrev' '
> +	git ls-tree --oid-only --abbrev=6 $tree >current &&
> +	git ls-tree --abbrev=6 $tree | awk "{print \$3}" > expected &&
> +	test_cmp current expected
> +'
> +
> +test_expect_failure 'usage: incompatible options: --name-only with --oid-only' '
> +	test_incompatible_usage git ls-tree --oid-only --name-only
> +'
> +
> +test_done