Fix Clock crash on empty string in timezones field

Also fixed timezones behavior: now waybar starting with the first timezone in timezones list and falling back to timezone field only if timezones omit or has no elements.

include/modules/clock.hpp

@@ -37,6 +37,7 @@ class Clock : public ALabel {
   auto calendar_text(const waybar_time& wtime) -> std::string;
   auto weekdays_header(const date::weekday& first_dow, std::ostream& os) -> void;
   auto first_day_of_week() -> date::weekday;
+  bool setTimeZone(Json::Value zone_name);
 };
 
 }  // namespace waybar::modules

man/waybar-clock.5.scd

@@ -24,7 +24,8 @@ The *clock* module displays the current date and time.
 *timezone*: ++
 	typeof: string ++
 	default: inferred local timezone ++
-	The timezone to display the time in, e.g. America/New_York.
+	The timezone to display the time in, e.g. America/New_York. ++
+	This field will be ignored if *timezones* field is set and have at least one value.
 
 *timezones*: ++
 	typeof: list of strings ++

src/modules/clock.cpp

@@ -15,10 +15,14 @@ using waybar::modules::waybar_time;
 
 waybar::modules::Clock::Clock(const std::string& id, const Json::Value& config)
     : ALabel(config, "clock", id, "{:%H:%M}", 60, false, false, true), fixed_time_zone_(false) {
-  if (config_["timezone"].isString()) {
+  if (config_["timezones"].isArray() && !config_["timezones"].empty()) {
+    time_zone_idx_ = 0;
+    setTimeZone(config_["timezones"][time_zone_idx_]);
+  } else {
+    setTimeZone(config_["timezone"]);
+  }
+  if (fixed_time_zone_) {
     spdlog::warn("As using a timezone, some format args may be missing as the date library haven't got a release since 2018.");
-    time_zone_ = date::locate_zone(config_["timezone"].asString());
-    fixed_time_zone_ = true;
   }
 
   if (config_["locale"].isString()) {
@@ -72,6 +76,17 @@ auto waybar::modules::Clock::update() -> void {
   ALabel::update();
 }
 
+bool waybar::modules::Clock::setTimeZone(Json::Value zone_name) {
+  if (!zone_name.isString() || zone_name.asString().empty()) {
+      fixed_time_zone_ = false;
+      return false;
+  }
+
+  time_zone_ = date::locate_zone(zone_name.asString());
+  fixed_time_zone_ = true;
+  return true;
+}
+
 bool waybar::modules::Clock::handleScroll(GdkEventScroll *e) {
   // defer to user commands if set
   if (config_["on-scroll-up"].isString() || config_["on-scroll-down"].isString()) {
@@ -92,14 +107,7 @@ bool waybar::modules::Clock::handleScroll(GdkEventScroll *e) {
   } else {
     time_zone_idx_ = time_zone_idx_ == 0 ? nr_zones - 1 : time_zone_idx_ - 1;
   }
-  auto zone_name = config_["timezones"][time_zone_idx_];
+  setTimeZone(config_["timezones"][time_zone_idx_]);
-  if (!zone_name.isString() || zone_name.empty()) {
-    fixed_time_zone_ = false;
-  } else {
-    time_zone_ = date::locate_zone(zone_name.asString());
-    fixed_time_zone_ = true;
-  }
-
   update();
   return true;
 }