shared/verbs: add flag VERB_OPTION_REQUIRED

src/shared/verbs.c

@@ -175,10 +175,11 @@ static int verb_add_help_one(Table *table, const Verb *verb) {
         assert(table);
         assert(verb);
 
-        bool is_default = FLAGS_SET(verb->flags, VERB_DEFAULT);
         _cleanup_free_ char *cell = NULL;
         int r;
 
+        bool is_default = FLAGS_SET(verb->flags, VERB_DEFAULT);
+
         /* The synopsis cell contains one line per entry in the argspec nulstr. An unset argspec is
          * equivalent to a single empty specification. */
         for (const char *spec = empty_to_null(verb->argspec);;) {
@@ -190,7 +191,8 @@ static int verb_add_help_one(Table *table, const Verb *verb) {
                                                  verb->verb,
                                                  spec ? " " : "",
                                                  strempty(spec),
-                                                 is_default ? "]" : "");
+                                                 is_default ? "]" : "",
+                                                 FLAGS_SET(verb->flags, VERB_OPTION_REQUIRED) ? " OPTION" : "");
                 if (!s)
                         return log_oom();
 
@@ -588,12 +590,16 @@ int _command_print_verb_help(
         if (cmd->pager_flags)
                 pager_open(*cmd->pager_flags);
 
+        const char *optionspec =
+                FLAGS_SET(verb->flags, VERB_OPTION_REQUIRED) ?
+                        " OPTION…" : verb->option_namespace ? " [OPTION…]" : "";
+
         /* If argspec is empty, print one line with no argspec. Use " " as placeholder for the empty spec. */
         NULSTR_FOREACH(spec, verb->argspec ?: " \0") {
                 bool some = !streq(spec, " ");
                 _cleanup_free_ char *line = strjoin(
                                 "[OPTION…] ", verb->verb,
-                                verb->option_namespace ? " [OPTION…]" : "",
+                                optionspec,
                                 some ? " " : NULL,
                                 some ? spec : NULL);
                 if (!line)

src/shared/verbs.h

@@ -28,10 +28,11 @@ typedef struct CommandDescription {
 } CommandDescription;
 
 typedef enum VerbFlags {
-        VERB_DEFAULT        = 1 << 0,  /* The verb to run if no verb is specified */
-        VERB_ONLINE_ONLY    = 1 << 1,  /* Just do nothing when running in chroot or offline */
-        VERB_COMMAND_MARKER = 1 << 2,  /* Header entry with command description */
-        VERB_GROUP_MARKER   = 1 << 3,  /* Fake verb entry to separate groups */
+        VERB_DEFAULT         = 1 << 0,  /* The verb to run if no verb is specified */
+        VERB_ONLINE_ONLY     = 1 << 1,  /* Just do nothing when running in chroot or offline */
+        VERB_OPTION_REQUIRED = 1 << 2,  /* The verb always requires an option to be present */
+        VERB_COMMAND_MARKER  = 1 << 3,  /* Header entry with command description */
+        VERB_GROUP_MARKER    = 1 << 4,  /* Fake verb entry to separate groups */
 } VerbFlags;
 
 /* Note: see the comment on struct Option in options.h for why _alignptr_ is required here. */

src/test/test-verbs.c

@@ -99,6 +99,9 @@ static const Verb introspect_verbs[] = {
           .argspec = "FORM1\0FORM2…\0", .help = "Alpha verb", .option_namespace = "test-verbs-alpha" },
         { .verb = "beta", .min_args = VERB_ANY, .max_args = VERB_ANY, .dispatch = noop_dispatcher,
           .help = "Beta verb" },
+        { .verb = "gamma", .flags = VERB_OPTION_REQUIRED,
+          .min_args = VERB_ANY, .max_args = VERB_ANY, .dispatch = noop_dispatcher,
+          .help = "Gamma verb" },
         {}
 };
 
@@ -121,6 +124,9 @@ TEST(command_print_verb_help) {
         ASSERT_OK(_command_print_verb_help(introspect_verbs, introspect_verbs + ELEMENTSOF(introspect_verbs) - 1,
                                            introspect_options, introspect_options + ELEMENTSOF(introspect_options) - 1,
                                            "beta"));
+        ASSERT_OK(_command_print_verb_help(introspect_verbs, introspect_verbs + ELEMENTSOF(introspect_verbs) - 1,
+                                           introspect_options, introspect_options + ELEMENTSOF(introspect_options) - 1,
+                                           "gamma"));
 }
 
 DEFINE_TEST_MAIN(LOG_INFO);