Add support for task expiration (#3546)

src/commands/CmdNews.cpp

@@ -172,6 +172,7 @@ std::vector<NewsItem> NewsItem::all () {
   std::vector<NewsItem> items;
   version2_6_0(items);
   version3_0_0(items);
+  version3_1_0(items);
   return items;
 }
 
@@ -537,6 +538,27 @@ void NewsItem::version3_0_0 (std::vector<NewsItem>& items) {
   items.push_back(sync);
 }
 
+void NewsItem::version3_1_0 (std::vector<NewsItem>& items) {
+  Version version("3.1.0");
+  NewsItem sync {
+    version,
+    /*title=*/"Purging and Expiring Tasks",
+    /*bg_title=*/"",
+    /*background=*/"",
+    /*punchline=*/
+    "Support for `task purge` has been restored, and new support added for automatically expiring\n"
+    "old tasks.\n\n"
+    /*update=*/
+    "The `task purge` command removes tasks entirely, in contrast to `task delete` which merely sets\n"
+    "the task status to 'Deleted'. This functionality existed in versions 2.x but was temporarily\n"
+    "removed in 3.0.\n\n"
+    "The new `expiration.on-sync` configuration parameter controls automatic expiration of old tasks.\n"
+    "An old task is one with status 'Deleted' that has not been modified in 180 days. This\n"
+    "functionality is optional and not enabled by default."
+  };
+  items.push_back(sync);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 int CmdNews::execute (std::string& output)
 {

src/commands/CmdNews.h

@@ -49,6 +49,7 @@ public:
   static std::vector<NewsItem> all();
   static void version2_6_0 (std::vector<NewsItem>&);
   static void version3_0_0 (std::vector<NewsItem>&);
+  static void version3_1_0 (std::vector<NewsItem>&);
 
 private:
   NewsItem (

src/commands/CmdShow.cpp

@@ -160,6 +160,7 @@ int CmdShow::execute (std::string& output)
     " due"
     " editor"
     " exit.on.missing.db"
+    " expiration.on-sync"
     " expressions"
     " fontunderline"
     " gc"

src/commands/CmdSync.cpp

@@ -106,7 +106,12 @@ int CmdSync::execute (std::string& output)
         << '\n';
   }
 
-  Context::getContext ().tdb2.sync(std::move(server), false);
+  Context &context = Context::getContext ();
+  context.tdb2.sync(std::move(server), false);
+
+  if (context.config.getBoolean ("expiration.on-sync")) {
+    context.tdb2.expire_tasks ();
+  }
 
   output = out.str ();
   return status;