Check for updates: edge cases when the message on the dashboard doesn't make sense.

lib/discourse_updates.rb

@@ -3,14 +3,30 @@ module DiscourseUpdates
   class << self
 
     def check_version
-      DiscourseVersionCheck.new(
-        latest_version: latest_version || Discourse::VERSION::STRING,
-        critical_updates: critical_updates_available?,
-        installed_version: Discourse::VERSION::STRING,
-        installed_sha: (Discourse.git_version == 'unknown' ? nil : Discourse.git_version),
-        missing_versions_count: missing_versions_count || nil
-        # TODO: more info, like links and release messages
-      )
+      version_info = if updated_at.nil?
+        DiscourseVersionCheck.new(
+          installed_version: Discourse::VERSION::STRING,
+          installed_sha: (Discourse.git_version == 'unknown' ? nil : Discourse.git_version),
+          updated_at: nil
+        )
+      else
+        DiscourseVersionCheck.new(
+          latest_version: latest_version,
+          critical_updates: critical_updates_available?,
+          installed_version: Discourse::VERSION::STRING,
+          installed_sha: (Discourse.git_version == 'unknown' ? nil : Discourse.git_version),
+          missing_versions_count: missing_versions_count,
+          updated_at: updated_at
+        )
+      end
+
+      if version_info.updated_at.nil? or
+          (version_info.missing_versions_count == 0 and version_info.latest_version != version_info.installed_version)
+        # Version check data is out of date.
+        Jobs.enqueue(:version_check, all_sites: true)
+      end
+
+      version_info
     end
 
     def latest_version
@@ -25,6 +41,15 @@ module DiscourseUpdates
       ($redis.get(critical_updates_available_key) || false) == 'true'
     end
 
+    def updated_at
+      t = $redis.get(updated_at_key)
+      t ? Time.zone.parse(t) : nil
+    end
+
+    def updated_at=(time_with_zone)
+      $redis.set updated_at_key, time_with_zone.as_json
+    end
+
     ['latest_version', 'missing_versions_count', 'critical_updates_available'].each do |name|
       eval "define_method :#{name}= do |arg|
         $redis.set #{name}_key, arg
@@ -45,5 +70,9 @@ module DiscourseUpdates
       def missing_versions_count_key
         'missing_versions_count'
       end
+
+      def updated_at_key
+        'last_version_check_at'
+      end
   end
 end