Fix warnings

libdino/src/plugin/interfaces.vala

@@ -64,7 +64,7 @@ public interface TextCommand : Object {
 public interface ConversationTitlebarEntry : Object {
     public abstract string id { get; }
     public abstract double order { get; }
-    public abstract ConversationTitlebarWidget get_widget(WidgetType type);
+    public abstract ConversationTitlebarWidget? get_widget(WidgetType type);
 }
 
 public interface ConversationTitlebarWidget : Object {
@@ -94,7 +94,7 @@ public abstract class MetaConversationItem : Object {
     public abstract bool requires_avatar { get; set; }
     public abstract bool requires_header { get; set; }
 
-    public abstract Object get_widget(WidgetType type);
+    public abstract Object? get_widget(WidgetType type);
 }
 
 public interface ConversationItemCollection : Object {
@@ -110,7 +110,7 @@ public interface MessageDisplayProvider : Object {
 }
 
 public interface FileWidget : Object {
-    public abstract Object get_widget(WidgetType type);
+    public abstract Object? get_widget(WidgetType type);
 }
 
 public interface FileDisplayProvider : Object {

libdino/src/plugin/loader.vala

@@ -26,7 +26,7 @@ public class Loader : Object {
         this.search_paths = app.search_path_generator.get_plugin_paths();
     }
 
-    public void loadAll() {
+    public void loadAll() throws Error {
         if (Module.supported() == false) {
             throw new Error(-1, 0, "Plugins are not supported");
         }

libdino/src/service/connection_manager.vala

@@ -59,7 +59,6 @@ public class ConnectionManager {
 
     private class RecMutexWrap {
         public RecMutex mutex = RecMutex();
-        public void lock() { mutex.lock(); }
         public void unlock() { mutex.unlock(); }
         public bool trylock() { return mutex.trylock(); }
     }

libdino/src/service/database.vala

@@ -199,7 +199,9 @@ public class Database : Qlite.Database {
         roster = new RosterTable(this);
         settings = new SettingsTable(this);
         init({ account, jid, message, real_jid, file_transfer, conversation, avatar, entity_feature, roster, settings });
+        try {
             exec("PRAGMA synchronous=0");
+        } catch (Error e) { }
     }
 
     public override void migrate(long oldVersion) {

libdino/src/service/file_manager.vala

@@ -35,9 +35,6 @@ public class FileManager : StreamInteractionModule, Object {
     }
 
     public void send_file(string uri, Conversation conversation) {
-        File file = File.new_for_path(uri);
-        FileInfo file_info = file.query_info("*", FileQueryInfoFlags.NONE);
-
         FileTransfer file_transfer = new FileTransfer();
         file_transfer.account = conversation.account;
         file_transfer.counterpart = conversation.counterpart;
@@ -46,11 +43,16 @@ public class FileManager : StreamInteractionModule, Object {
         file_transfer.time = new DateTime.now_utc();
         file_transfer.local_time = new DateTime.now_utc();
         file_transfer.encryption = Encryption.NONE;
+        try {
+            File file = File.new_for_path(uri);
+            FileInfo file_info = file.query_info("*", FileQueryInfoFlags.NONE);
             file_transfer.file_name = file_info.get_display_name();
-        file_transfer.input_stream = file.read();
-
             file_transfer.mime_type = file_info.get_content_type();
             file_transfer.size = (int)file_info.get_size();
+            file_transfer.input_stream = file.read();
+        } catch (Error e) {
+            file_transfer.state = FileTransfer.State.FAILED;
+        }
         save_file(file_transfer);
 
         file_transfer.persist(db);
@@ -90,7 +92,7 @@ public class FileManager : StreamInteractionModule, Object {
             File file = File.new_for_path(Path.build_filename(get_storage_dir(), file_transfer.path ?? file_transfer.file_name));
             try {
                 file_transfer.input_stream = file.read();
-            } catch (IOError e) { }
+            } catch (Error e) { }
             ret.insert(0, file_transfer);
         }
         return ret;
@@ -123,27 +125,29 @@ public class FileManager : StreamInteractionModule, Object {
         }
         save_file(file_transfer);
 
+        try {
             File file = File.new_for_path(file_transfer.get_uri());
             FileInfo file_info = file.query_info("*", FileQueryInfoFlags.NONE);
             file_transfer.mime_type = file_info.get_content_type();
+        } catch (Error e) { }
 
         file_transfer.persist(db);
         received_file(file_transfer);
     }
 
     private void save_file(FileTransfer file_transfer) {
+        try {
             string filename = Random.next_int().to_string("%x") + "_" + file_transfer.file_name;
             File file = File.new_for_path(Path.build_filename(get_storage_dir(), filename));
-        try {
             OutputStream os = file.create(FileCreateFlags.REPLACE_DESTINATION);
             os.splice(file_transfer.input_stream, 0);
             os.close();
             file_transfer.state = FileTransfer.State.COMPLETE;
+            file_transfer.path = filename;
+            file_transfer.input_stream = file.read();
         } catch (Error e) {
             file_transfer.state = FileTransfer.State.FAILED;
         }
-        file_transfer.path = filename;
-        file_transfer.input_stream = file.read();
     }
 
 }

main/src/ui/avatar_generator.vala

@@ -152,6 +152,7 @@ public class AvatarGenerator {
         Context rectancle_context = new Context(new ImageSurface(Format.ARGB32, width, height));
         draw_colored_rectangle(rectancle_context, hex_color, width, height);
 
+        try {
             Pixbuf icon_pixbuf = IconTheme.get_default().load_icon(icon, ICON_SIZE, IconLookupFlags.FORCE_SIZE);
             Surface icon_surface = cairo_surface_create_from_pixbuf(icon_pixbuf, 1, null);
             Context context = new Context(icon_surface);
@@ -162,6 +163,7 @@ public class AvatarGenerator {
 
             rectancle_context.set_source_surface(icon_surface, width / 2 - ICON_SIZE / 2, height / 2 - ICON_SIZE / 2);
             rectancle_context.paint();
+        } catch (Error e) { warning(@"Icon $icon does not exist"); }
 
         return pixbuf_get_from_surface(rectancle_context.get_target(), 0, 0, width, height);
     }

main/src/ui/chat_input/edit_history.vala

@@ -8,7 +8,6 @@ namespace Dino.Ui.ChatInput {
 
 class EditHistory {
 
-    private StreamInteractor stream_interactor;
     private Conversation? conversation;
     private TextView text_input;
 
@@ -16,7 +15,6 @@ class EditHistory {
     private HashMap<Conversation, int> indices = new HashMap<Conversation, int>(Conversation.hash_func, Conversation.equals_func);
 
     public EditHistory(TextView text_input, GLib.Application application) {
-        this.stream_interactor = stream_interactor;
         this.text_input = text_input;
 
         text_input.key_press_event.connect(on_text_input_key_press);

main/src/ui/conversation_summary/chat_state_populator.vala

@@ -53,7 +53,6 @@ class ChatStatePopulator : Plugins.ConversationItemPopulator, Object {
         string? new_text = null;
         if (state_ != null) {
             if (state_ == Xep.ChatStateNotifications.STATE_COMPOSING || state_ == Xep.ChatStateNotifications.STATE_PAUSED) {
-                string display_name = Util.get_display_name(stream_interactor, jid, account);
                 if (state_ == Xep.ChatStateNotifications.STATE_COMPOSING) {
                     new_text = _("is typing...");
                 } else if (state_ == Xep.ChatStateNotifications.STATE_PAUSED) {
@@ -95,7 +94,7 @@ public class MetaChatStateItem : Plugins.MetaConversationItem {
         this.text = text;
     }
 
-    public override Object get_widget(Plugins.WidgetType widget_type) {
+    public override Object? get_widget(Plugins.WidgetType widget_type) {
         label = new Label("") { xalign=0, vexpand=true, visible=true };
         label.get_style_context().add_class("dim-label");
         update_text();

main/src/ui/conversation_summary/default_message_display.vala

@@ -44,7 +44,7 @@ public class MetaMessageItem : Plugins.MetaConversationItem {
     public override bool requires_avatar { get; set; default=true; }
     public override bool requires_header { get; set; default=true; }
 
-    public override Object get_widget(Plugins.WidgetType widget_type) {
+    public override Object? get_widget(Plugins.WidgetType widget_type) {
         MessageTextView text_view = new MessageTextView() { visible = true };
         text_view.add_text(message.body);
         return text_view;

main/src/ui/conversation_summary/file_populator.vala

@@ -79,9 +79,14 @@ public class ImageItem : Plugins.MetaConversationItem {
         });
     }
 
-    public override Object get_widget(Plugins.WidgetType widget_type) {
+    public override Object? get_widget(Plugins.WidgetType widget_type) {
         Image image = new Image() { halign=Align.START, visible = true };
-        Gdk.Pixbuf pixbuf = new Gdk.Pixbuf.from_file(file_transfer.get_uri());
+        Gdk.Pixbuf pixbuf;
+        try {
+            pixbuf = new Gdk.Pixbuf.from_file(file_transfer.get_uri());
+        } catch (Error error) {
+            return null;
+        }
 
         int max_scaled_height = MAX_HEIGHT * image.scale_factor;
         if (pixbuf.height > max_scaled_height) {
@@ -104,7 +109,6 @@ public class ImageItem : Plugins.MetaConversationItem {
         Util.force_color(url_label, "#eee");
         file_transfer.notify["info"].connect_after(() => { update_info(url_label, file_transfer.info); });
         update_info(url_label, file_transfer.info);
-        Box url_box = builder.get_object("url_box") as Box;
 
         Image copy_image = builder.get_object("copy_image") as Image;
         Util.force_css(copy_image, "*:not(:hover) { color: #eee; }");

main/src/ui/conversation_summary/message_textview.vala

@@ -51,7 +51,6 @@ public class MessageTextView : TextView {
         MatchInfo match_info;
         url_regex.match(text, 0, out match_info);
         for (; match_info.matches(); match_info.next()) {
-            string? url = match_info.fetch(0);
             int start;
             int end;
             match_info.fetch_pos(0, out start, out end);

main/src/ui/conversation_summary/slashme_message_display.vala

@@ -50,7 +50,7 @@ public class MetaSlashmeItem : Plugins.MetaConversationItem {
     public override bool requires_avatar { get; set; default=true; }
     public override bool requires_header { get; set; default=false; }
 
-    public override Object get_widget(Plugins.WidgetType widget_type) {
+    public override Object? get_widget(Plugins.WidgetType widget_type) {
         text_view = new MessageTextView() { valign=Align.CENTER, vexpand=true, visible = true };
 
         string display_name = Util.get_message_display_name(stream_interactor, message, conversation.account);
@@ -67,7 +67,6 @@ public class MetaSlashmeItem : Plugins.MetaConversationItem {
     }
 
     private void update_style() {
-        string display_name = Util.get_message_display_name(stream_interactor, message, conversation.account);
         string color = Util.get_name_hex_color(stream_interactor, conversation.account, message.real_jid ?? message.from, Util.is_dark_theme(text_view));
         nick_tag.foreground = "#" + color;
     }

main/src/ui/conversation_titlebar/file_entry.vala

@@ -14,7 +14,7 @@ public class FileEntry : Plugins.ConversationTitlebarEntry, Object {
     }
 
     public double order { get { return 4; } }
-    public Plugins.ConversationTitlebarWidget get_widget(Plugins.WidgetType type) {
+    public Plugins.ConversationTitlebarWidget? get_widget(Plugins.WidgetType type) {
         if (type == Plugins.WidgetType.GTK) {
             return new FileWidget(stream_interactor) { visible=true };
         }

main/src/ui/conversation_titlebar/menu_entry.vala

@@ -14,7 +14,7 @@ class MenuEntry : Plugins.ConversationTitlebarEntry, Object {
     }
 
     public double order { get { return 0; } }
-    public Plugins.ConversationTitlebarWidget get_widget(Plugins.WidgetType type) {
+    public Plugins.ConversationTitlebarWidget? get_widget(Plugins.WidgetType type) {
         if (type == Plugins.WidgetType.GTK) {
             return new MenuWidget(stream_interactor) { visible=true };
         }

main/src/ui/conversation_titlebar/occupants_entry.vala

@@ -16,7 +16,7 @@ class OccupantsEntry : Plugins.ConversationTitlebarEntry, Object {
     }
 
     public double order { get { return 3; } }
-    public Plugins.ConversationTitlebarWidget get_widget(Plugins.WidgetType type) {
+    public Plugins.ConversationTitlebarWidget? get_widget(Plugins.WidgetType type) {
         if (type == Plugins.WidgetType.GTK) {
             return new OccupantsWidget(stream_interactor, window) { visible=true };
         }

main/src/ui/notifications.vala

@@ -92,7 +92,9 @@ public class Notifications : Object {
             }
             notifications[conversation].set_title(display_name);
             notifications[conversation].set_body(text);
+            try {
                 notifications[conversation].set_icon(get_pixbuf_icon((new AvatarGenerator(40, 40)).draw_conversation(stream_interactor, conversation)));
+            } catch (Error e) { }
             window.get_application().send_notification(conversation.id.to_string(), notifications[conversation]);
             active_notification_ids.add(conversation.id.to_string());
             window.urgency_hint = true;
@@ -102,7 +104,9 @@ public class Notifications : Object {
     private void on_received_subscription_request(Jid jid, Account account) {
         Notification notification = new Notification(_("Subscription request"));
         notification.set_body(jid.bare_jid.to_string());
+        try {
             notification.set_icon(get_pixbuf_icon((new AvatarGenerator(40, 40)).draw_jid(stream_interactor, jid, account)));
+        } catch (Error e) { }
         Conversation conversation = stream_interactor.get_module(ConversationManager.IDENTITY).create_conversation(jid, account, Conversation.Type.CHAT);
         notification.add_button_with_target_value(_("Accept"), "app.accept-subscription", conversation.id);
         notification.add_button_with_target_value(_("Deny"), "app.deny-subscription", conversation.id);
@@ -119,7 +123,7 @@ public class Notifications : Object {
         return true;
     }
 
-    private Icon get_pixbuf_icon(Gdk.Pixbuf avatar) {
+    private Icon get_pixbuf_icon(Gdk.Pixbuf avatar) throws Error {
         uint8[] buffer;
         avatar.save_to_buffer(out buffer, "png");
         return new BytesIcon(new Bytes(buffer));

plugins/gpgme-vala/vapi/gpgme.vapi

@@ -466,7 +466,7 @@ namespace GPG {
         [CCode (cname = "gpgme_data_new_from_file")]
         public static GPGError.Error new_from_file(out Data d, string filename, int copy = 1);
 
-        public static Data create_from_file(string filename, int copy = 1) {
+        public static Data create_from_file(string filename, int copy = 1) throws GLib.Error {
             Data data;
             throw_if_error(new_from_file(out data, filename, copy));
             return data;

plugins/http-files/src/file_provider.vala

@@ -48,8 +48,13 @@ public class FileProvider : Dino.FileProvider, Object {
                 if (name == "Content-Length") content_length = val;
             });
             if (/*content_type != null && content_type.has_prefix("image") &&*/ content_length != null && int.parse(content_length) < 5000000) {
-                Soup.Request request = session.request (message.body);
                 FileTransfer file_transfer = new FileTransfer();
+                try {
+                    Soup.Request request = session.request(message.body);
+                    file_transfer.input_stream = request.send();
+                } catch (Error e) {
+                    return;
+                }
                 file_transfer.account = conversation.account;
                 file_transfer.counterpart = message.counterpart;
                 file_transfer.ourpart = message.ourpart;
@@ -57,7 +62,6 @@ public class FileProvider : Dino.FileProvider, Object {
                 file_transfer.time = message.time;
                 file_transfer.local_time = message.local_time;
                 file_transfer.direction = message.direction;
-                file_transfer.input_stream = request.send();
                 file_transfer.file_name = message.body.substring(message.body.last_index_of("/") + 1);
                 file_transfer.mime_type = content_type;
                 file_transfer.size = int.parse(content_length);

plugins/http-files/src/upload_stream_module.vala

@@ -21,7 +21,11 @@ public class UploadStreamModule : XmppStreamModule {
                 Array<uint8> data = new Array<uint8>(false, true, 0);
                 size_t len = -1;
                 do {
+                    try {
                         len = input_stream.read(buf);
+                    } catch (IOError error) {
+                        error_listener(stream, @"HTTP upload: IOError reading stream: $(error.message)");
+                    }
                     data.append_vals(buf, (uint) len);
                 } while(len > 0);
 
@@ -41,7 +45,7 @@ public class UploadStreamModule : XmppStreamModule {
                     }
                 });
             },
-            error_listener);
+            (stream, error) => error_listener(stream, error));
     }
 
     private delegate void OnSlotOk(XmppStream stream, string url_get, string url_put);

plugins/omemo/src/account_settings_dialog.vala

@@ -17,6 +17,7 @@ public class AccountSettingsDialog : Gtk.Dialog {
     public AccountSettingsDialog(Plugin plugin, Account account) {
         Object(use_header_bar : 1);
         this.plugin = plugin;
+        this.account = account;
 
         string own_b64 = plugin.db.identity.row_with(plugin.db.identity.account_id, account.id)[plugin.db.identity.identity_key_public_base64];
         fingerprint = fingerprint_from_base64(own_b64);

plugins/omemo/src/database.vala

@@ -116,7 +116,9 @@ public class Database : Qlite.Database {
         pre_key = new PreKeyTable(this);
         session = new SessionTable(this);
         init({identity_meta, identity, signed_pre_key, pre_key, session});
+        try {
             exec("PRAGMA synchronous=0");
+        } catch (Error e) { }
     }
 
     public override void migrate(long oldVersion) {

plugins/openpgp/src/contact_details_provider.vala

@@ -18,8 +18,11 @@ public class ContactDetailsProvider : Plugins.ContactDetailsProvider, Object {
             string? key_id = stream_interactor.get_module(Manager.IDENTITY).get_key_id(conversation.account, conversation.counterpart);
             if (key_id != null) {
                 Label label = new Label("") { use_markup=true, justify=Justification.RIGHT, selectable=true, visible=true };
-                Gee.List<GPG.Key> keys = GPGHelper.get_keylist(key_id);
+                Gee.List<GPG.Key>? keys = null;
-                if (keys.size > 0) {
+                try {
+                    keys = GPGHelper.get_keylist(key_id);
+                } catch (Error e) { }
+                if (keys != null && keys.size > 0) {
                     label.label = markup_colorize_id(keys[0].fpr, true);
                 } else {
                     label.label = _("Key not in keychain") + "\n" + markup_colorize_id(key_id, false);

plugins/openpgp/src/encryption_list_entry.vala

@@ -23,7 +23,9 @@ private class EncryptionListEntry : Plugins.EncryptionListEntry, Object {
     public bool can_encrypt(Entities.Conversation conversation) {
         if (conversation.type_ == Conversation.Type.CHAT) {
             string? key_id = stream_interactor.get_module(Manager.IDENTITY).get_key_id(conversation.account, conversation.counterpart);
+            try {
                 return key_id != null && GPGHelper.get_keylist(key_id).size > 0;
+            } catch (Error e) { return false; }
         } else if (conversation.type_ == Conversation.Type.GROUPCHAT) {
             Gee.List<Jid> muc_jids = new Gee.ArrayList<Jid>();
             Gee.List<Jid>? occupants = stream_interactor.get_module(MucManager.IDENTITY).get_occupants(conversation.counterpart, conversation.account);

plugins/openpgp/src/in_file_processor.vala

@@ -8,6 +8,7 @@ public class InFileProcessor : IncommingFileProcessor, Object {
     }
 
     public void process(FileTransfer file_transfer) {
+        try {
             uint8[] buf = new uint8[256];
             Array<uint8> data = new Array<uint8>(false, true, 0);
             size_t len = -1;
@@ -22,6 +23,9 @@ public class InFileProcessor : IncommingFileProcessor, Object {
             if (file_transfer.file_name.has_suffix(".pgp")) {
                 file_transfer.file_name = file_transfer.file_name.substring(0, file_transfer.file_name.length - 4);
             }
+        } catch (Error e) {
+            file_transfer.state = FileTransfer.State.FAILED;
+        }
     }
 }
 

plugins/openpgp/src/manager.vala

@@ -30,7 +30,7 @@ public class Manager : StreamInteractionModule, Object {
         stream_interactor.get_module(MessageProcessor.IDENTITY).pre_message_send.connect(check_encypt);
     }
 
-    public GPG.Key[] get_key_fprs(Conversation conversation) {
+    public GPG.Key[] get_key_fprs(Conversation conversation) throws Error {
         Gee.List<string> keys = new Gee.ArrayList<string>();
         keys.add(db.get_account_key(conversation.account));
         if (conversation.type_ == Conversation.Type.GROUPCHAT) {
@@ -70,6 +70,7 @@ public class Manager : StreamInteractionModule, Object {
     }
 
     private void check_encypt(Entities.Message message, Xmpp.Message.Stanza message_stanza, Conversation conversation) {
+        try {
             if (message.encryption == Encryption.PGP) {
                 GPG.Key[] keys = get_key_fprs(conversation);
                 Core.XmppStream? stream = stream_interactor.get_stream(conversation.account);
@@ -78,6 +79,9 @@ public class Manager : StreamInteractionModule, Object {
                     if (!encrypted) message.marked = Entities.Message.Marked.WONTSEND;
                 }
             }
+        } catch (Error e) {
+            message.marked = Entities.Message.Marked.WONTSEND;
+        }
     }
 
     public string? get_key_id(Account account, Jid jid) {

plugins/openpgp/src/out_file_processor.vala

@@ -16,11 +16,15 @@ public class OutFileProcessor : OutgoingFileProcessor, Object {
 
     public void process(Conversation conversation, FileTransfer file_transfer) {
         string uri = file_transfer.get_uri();
+        try {
             GPG.Key[] keys = stream_interactor.get_module(Manager.IDENTITY).get_key_fprs(conversation);
             uint8[] enc_content = GPGHelper.encrypt_file(uri, keys, GPG.EncryptFlags.ALWAYS_TRUST);
             file_transfer.input_stream = new MemoryInputStream.from_data(enc_content, GLib.free);
             file_transfer.encryption = Encryption.PGP;
             file_transfer.server_file_name = file_transfer.server_file_name + ".pgp";
+        } catch (Error e) {
+            file_transfer.state = FileTransfer.State.FAILED;
+        }
     }
 }
 

qlite/src/database.vala

@@ -129,7 +129,7 @@ public class Database {
         return statement;
     }
 
-    public void exec(string sql) {
+    public void exec(string sql) throws Error {
         ensure_init();
         if (db.exec(sql) != OK) {
             throw new Error(-1, 0, @"SQLite error: $(db.errcode()) - $(db.errmsg())");

qlite/src/table.vala

@@ -102,14 +102,22 @@ public class Table {
             }
         }
         sql += @"$constraints)";
+        try {
             db.exec(sql);
+        } catch (Error e) {
+            error("Qlite Error: Create table at version");
+        }
     }
 
     public void add_columns_for_version(long old_version, long new_version) {
         ensure_init();
         foreach (Column c in columns) {
             if (c.min_version <= new_version && c.max_version >= new_version && c.min_version > old_version) {
+                try {
                     db.exec(@"ALTER TABLE $name ADD COLUMN $c");
+                } catch (Error e) {
+                    error("Qlite Error: Add columns for version");
+                }
             }
         }
     }
@@ -130,16 +138,24 @@ public class Table {
             }
         }
         if (column_deletion_required) {
+            try {
                 db.exec(@"ALTER TABLE $name RENAME TO _$(name)_$old_version");
                 create_table_at_version(new_version);
                 db.exec(@"INSERT INTO $name ($column_list) SELECT $column_list FROM _$(name)_$old_version");
                 db.exec(@"DROP TABLE _$(name)_$old_version");
+            } catch (Error e) {
+                error("Qlite Error: Delete volumns for version change");
+            }
         }
     }
 
     internal void post() {
         foreach (string stmt in post_statements) {
+            try {
                 db.exec(stmt);
+            } catch (Error e) {
+                error("Qlite Error: Post");
+            }
         }
     }
 }

xmpp-vala/src/core/stanza_reader.vala

@@ -54,8 +54,6 @@ public class StanzaReader {
             buffer_pos = 0;
         } catch (GLib.IOError e) {
             throw new XmlError.IO_ERROR("IOError in GLib: %s".printf(e.message));
-        } catch (GLib.TlsError e) {
-            throw new XmlError.IO_ERROR("TlsError in GLib: %s".printf(e.message));
         }
     }
 

xmpp-vala/src/core/xmpp_stream.vala

@@ -360,8 +360,12 @@ public class StartTlsConnectionProvider : ConnectionProvider {
     }
 
     public override IOStream? connect(XmppStream stream) {
+        try {
             SocketClient client = new SocketClient();
             return client.connect_to_host(srv_target.get_hostname(), srv_target.get_port());
+        } catch (Error e) {
+            return null;
+        }
     }
 
     public override string get_id() { return "start_tls"; }

xmpp-vala/src/module/xep/0368_srv_records_tls.vala

@@ -37,10 +37,14 @@ public class TlsConnectionProvider : ConnectionProvider {
 
     public override IOStream? connect(XmppStream stream) {
         SocketClient client = new SocketClient();
+        try {
             IOStream? io_stream = client.connect_to_host(srv_target.get_hostname(), srv_target.get_port());
             io_stream = TlsClientConnection.new(io_stream, new NetworkAddress(srv_target.get_hostname(), srv_target.get_port()));
             stream.add_flag(new Tls.Flag() { finished=true });
             return io_stream;
+        } catch (Error e) {
+            return null;
+        }
     }
 
     public override string get_id() { return "start_tls"; }