Fix error spam in logs due to missing cron month

app/Models/Schedule.php

@@ -122,13 +122,14 @@ class Schedule extends Model
      * Returns the schedule's execution crontab entry as a string.
      *
      * @return \Carbon\CarbonImmutable
+     * @throws \Exception
      */
     public function getNextRunDate()
     {
         $formatted = sprintf('%s %s %s %s %s', $this->cron_minute, $this->cron_hour, $this->cron_day_of_month, $this->cron_month, $this->cron_day_of_week);
 
         return CarbonImmutable::createFromTimestamp(
-            CronExpression::factory($formatted)->getNextRunDate()->getTimestamp()
+            (new CronExpression($formatted))->getNextRunDate()->getTimestamp()
         );
     }
 

database/migrations/2021_03_21_104718_force_cron_month_field_to_have_value_if_missing.php

@@ -0,0 +1,31 @@
+<?php
+
+use Illuminate\Support\Facades\DB;
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class ForceCronMonthFieldToHaveValueIfMissing extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::table('schedules', function (Blueprint $table) {
+            DB::update("UPDATE `schedules` SET `cron_month` = '*' WHERE `cron_month` = ''");
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        // No down function.
+    }
+}