Detect ungraceful exits, and backup modified buffers in these cases

src/client.cc

@@ -86,9 +86,9 @@ void Client::handle_available_input(EventMode mode)
         context().print_status({ error.what().str(), get_face("Error") });
         context().hooks().run_hook("RuntimeError", error.what(), context());
     }
-    catch (Kakoune::client_removed&)
+    catch (Kakoune::client_removed& removed)
     {
-        ClientManager::instance().remove_client(*this);
+        ClientManager::instance().remove_client(*this, removed.graceful);
     }
 }
 

src/client_manager.cc

@@ -50,9 +50,9 @@ Client* ClientManager::create_client(std::unique_ptr<UserInterface>&& ui,
         client->context().hooks().run_hook("RuntimeError", error.what(),
                                            client->context());
     }
-    catch (Kakoune::client_removed&)
+    catch (Kakoune::client_removed& removed)
     {
-        m_clients.pop_back();
+        remove_client(*client, removed.graceful);
         return nullptr;
     }
 
@@ -69,13 +69,16 @@ void ClientManager::handle_pending_inputs() const
         client->handle_available_input(EventMode::Pending);
 }
 
-void ClientManager::remove_client(Client& client)
+void ClientManager::remove_client(Client& client, bool graceful)
 {
     auto it = find_if(m_clients,
                       [&](const std::unique_ptr<Client>& ptr)
                       { return ptr.get() == &client; });
     kak_assert(it != m_clients.end());
     m_clients.erase(it);
+
+    if (not graceful and m_clients.empty())
+        BufferManager::instance().backup_modified_buffers();
 }
 
 WindowAndSelections ClientManager::get_free_window(Buffer& buffer)

src/client_manager.hh

@@ -7,7 +7,12 @@
 namespace Kakoune
 {
 
-struct client_removed{};
+struct client_removed
+{
+    client_removed(bool graceful) : graceful{graceful} {}
+
+    const bool graceful;
+};
 
 struct WindowAndSelections
 {
@@ -39,7 +44,7 @@ public:
     Client*  get_client_ifp(StringView name);
     Client&  get_client(StringView name);
     bool validate_client_name(StringView name) const;
-    void remove_client(Client& client);
+    void remove_client(Client& client, bool graceful);
 
     using ClientList = Vector<std::unique_ptr<Client>, MemoryDomain::Client>;
     using iterator = ClientList::const_iterator;

src/commands.cc

@@ -299,7 +299,7 @@ void quit()
         }
     }
     // unwind back to this client event handler.
-    throw client_removed{};
+    throw client_removed{ true };
 }
 
 const CommandDesc quit_cmd = {

src/main.cc

@@ -309,7 +309,7 @@ void create_local_client(std::unique_ptr<UserInterface> ui, StringView init_comm
 
     signal(SIGHUP, [](int) {
         if (client)
-            ClientManager::instance().remove_client(*client);
+            ClientManager::instance().remove_client(*client, false);
         client = nullptr;
     });
 }

src/remote.cc

@@ -391,12 +391,12 @@ Key RemoteUI::get_key()
     }
     catch (peer_disconnected&)
     {
-        throw client_removed{};
+        throw client_removed{ false };
     }
     catch (socket_error&)
     {
         write_to_debug_buffer("ungraceful deconnection detected");
-        throw client_removed{};
+        throw client_removed{ false };
     }
 }