[PATCH v6 05/13] git.c: convert --list-* to --list-cmds=*

[Nguyễn Thái Ngọc Duy]

Even if these are hidden options, let's make them a bit more generic
since we're introducing more listing types shortly. The code is
structured to allow combining multiple listing types together because
we will soon add more types the 'builtins'.

'parseopt' remains separate because it has separate (SPC) to match
git-completion.bash needs and will not combine with others.
---
 contrib/completion/git-completion.bash |  2 +-
 git.c                                  | 30 ++++++++++++++++++++------
 t/t0012-help.sh                        |  2 +-
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/contrib/completion/git-completion.bash 
b/contrib/completion/git-completion.bash
index a757073945..3556838759 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -3049,7 +3049,7 @@ __git_complete_common () {
 __git_cmds_with_parseopt_helper=
 __git_support_parseopt_helper () {
        test -n "$__git_cmds_with_parseopt_helper" ||
-               __git_cmds_with_parseopt_helper="$(__git 
--list-parseopt-builtins)"
+               __git_cmds_with_parseopt_helper="$(__git --list-cmds=parseopt)"
 
        case " $__git_cmds_with_parseopt_helper " in
        *" $1 "*)
diff --git a/git.c b/git.c
index 3a89893712..b2842a22e2 100644
--- a/git.c
+++ b/git.c
@@ -38,6 +38,23 @@ static int use_pager = -1;
 
 static void list_builtins(unsigned int exclude_option, char sep);
 
+static int list_cmds(const char *spec)
+{
+       while (*spec) {
+               const char *sep = strchrnul(spec, ',');
+               int len = sep - spec;
+
+               if (len == 8 && !strncmp(spec, "builtins", 8))
+                       list_builtins(0, '\n');
+               else
+                       die(_("unsupported command listing type '%s'"), spec);
+               spec += len;
+               if (*spec == ',')
+                       spec++;
+       }
+       return 0;
+}
+
 static void commit_pager_choice(void) {
        switch (use_pager) {
        case 0:
@@ -223,12 +240,13 @@ static int handle_options(const char ***argv, int *argc, 
int *envchanged)
                        }
                        (*argv)++;
                        (*argc)--;
-               } else if (!strcmp(cmd, "--list-builtins")) {
-                       list_builtins(0, '\n');
-                       exit(0);
-               } else if (!strcmp(cmd, "--list-parseopt-builtins")) {
-                       list_builtins(NO_PARSEOPT, ' ');
-                       exit(0);
+               } else if (skip_prefix(cmd, "--list-cmds=", &cmd)) {
+                       if (!strcmp(cmd, "parseopt")) {
+                               list_builtins(NO_PARSEOPT, ' ');
+                               exit(0);
+                       } else {
+                               exit(list_cmds(cmd));
+                       }
                } else {
                        fprintf(stderr, _("unknown option: %s\n"), cmd);
                        usage(git_usage_string);
diff --git a/t/t0012-help.sh b/t/t0012-help.sh
index c096f33505..3c91a9024a 100755
--- a/t/t0012-help.sh
+++ b/t/t0012-help.sh
@@ -59,7 +59,7 @@ test_expect_success 'git help' '
 '
 
 test_expect_success 'generate builtin list' '
-       git --list-builtins >builtins
+       git --list-cmds=builtins >builtins
 '
 
 while read builtin
-- 
2.17.0.705.g3525833791