fix(timer_module): Ensure that interval > 0 (#2274)

Since 3.5.0, we use m_interval for a modulo operation, this crashes the
bar if the interval is 0. A non-positive interval shouldn't be allowed
anyway, so we now throw an exception in that case.

Fixes #2273

include/modules/meta/timer_module.hpp

@@ -17,6 +17,20 @@ namespace modules {
     }
 
    protected:
+    /**
+     * Loads and sets the interval for this module.
+     *
+     * Will throw an exception if a non-positive (<= 0) number is given.
+     */
+    void set_interval(interval_t def) {
+      m_interval = this->m_conf.template get<decltype(m_interval)>(this->name(), "interval", def);
+
+      if (m_interval <= 0s) {
+        throw module_error(
+            this->name() + ": 'interval' must be larger than 0 (got '" + to_string(m_interval.count()) + "s')");
+      }
+    }
+
     void runner() {
       this->m_log.trace("%s: Thread id = %i", this->name(), concurrency_util::thread_id(this_thread::get_id()));