new: better help message with charm actions listed as commands

bin/compose-core

@@ -2650,6 +2650,43 @@ get_docker_compose_single_opts_list() {
     echo "$opts_list" | single_opts_filter
 }
 
+display_commands_help() {
+    local charm_actions
+    echo
+    echo "${WHITE}Commands${NORMAL} (thanks to docker-compose):"
+    get_docker_compose_commands_help | sed -r "s/  ([a-z]+)(\s+)/  ${DARKCYAN}\1${NORMAL}\2/g"
+    charm_actions_help=$(get_docker_charm_action_help) || return 1
+    if [ "$charm_actions_help" ]; then
+        echo
+        echo "${WHITE}Charm actions${NORMAL}:"
+        printf "%s\n" "$charm_actions_help" | \
+            sed -r "s/^    ([a-z0-9-]+)(\s+)([a-z0-9-]+)(\s+)/    ${DARKCYAN}\1${NORMAL}\2${DARKYELLOW}\3${NORMAL}\4/g"
+    fi
+}
+
+get_docker_charm_action_help() {
+    local services service charm relation_name target_service relation_config \
+          target_charm
+    services=($(get_compose_yml_content | shyaml keys 2>/dev/null))
+    for service in "${services[@]}"; do
+        out=$(
+            charm=$(get_service_charm "$service") || return 1
+            for action in $(charm.ls_direct_actions "$charm"); do
+                printf "    %-28s %s\n" "$action $service" "Direct action from ${DARKPINK}$charm${NORMAL}"
+            done
+            while read-0 relation_name target_service _relation_config _tech_dep; do
+                target_charm=$(get_service_charm "$target_service") || return 1
+                for action in $(charm.ls_relation_actions "$target_charm" "$relation_name"); do
+                    printf "    %-28s %s\n" "$action $service" "Indirect action from ${DARKPINK}$target_charm${NORMAL}"
+                done
+            done < <(get_compose_relations "$service")
+        )
+        if [ "$out" ]; then
+            echo "  for ${DARKYELLOW}$service${NORMAL}:"
+            printf "%s\n" "$out"
+        fi
+    done
+}
 
 display_help() {
     print_help
@@ -2671,9 +2708,7 @@ display_help() {
 
     get_docker_compose_opts_help | remove_options_in_option_help_msg --version --help --verbose |
         filter_docker_compose_help_message
-    echo
-    echo "${WHITE}Commands${NORMAL} (thanks to docker-compose):"
-    get_docker_compose_commands_help | sed -r "s/  ([a-z]+)(\s+)/  ${DARKCYAN}\1${NORMAL}\2/g"
+    display_commands_help
 }
 
 
@@ -3082,6 +3117,11 @@ charm.sanity_checks || die "Sanity checks about charm-store failed. Please corre
 
 if [ -z "$is_docker_compose_action" -a "$action" ]; then
     action_service=${remainder_args[0]}
+    if [ -z "$action_service" ]; then
+        err "No such command or action: ${DARKCYAN}$action${NORMAL}"
+        display_commands_help
+        exit 1
+    fi
     remainder_args=("${remainder_args[@]:1}")
     if has_service_action "$action_service" "$action" >/dev/null; then
         is_service_action=true