Retain QsciAPIs lexer_api as part of lexer_octave_gui object (bug #37359) This way, it may be deleted upon deconstruction and not cause segmentation fault at startup * file-editor-tab.cc, file-editor-tab.h (file_editor_tab::update_tracked_file): Delete. (file_editor_tab::set_file_name): Rather than clear whole list, just subtract out the old file name then add the new name. (file_editor_tab::load_file): Remove update_tracked_file, it's part of set_file_name. (file_editor_tab::file_has_changed): Remove update_tracked_file, it's part of set_file_name. (file_editor_tab::save_file): Move file close before set_file_name so watcher doesn't notice. Remove inelegant code that solved this by clearing watcher files. * lexer-octave-gui.cc, file-editor-tab.cc (file_editor_tab::update_lexer, lexer_octave_gui::lexer_octave_gui, lexer_octave_gui : public QsciLexer): Move all the lexer preparatory code to the constructor so that lexer_api can be retained as part of object. (lexer_octave_gui::~lexer_octave_gui): Make destructor non-virtual and delete lexer_gui when done. * octave-gui.cc, main-window-h, main-window.cc, file-editor.cc (octave_start_gui, file_editor::construct): Move read_settings from constructor to after construction in octave_start_gui so that no signal occur referencing a partially constructed object. * file-editor.cc (file_editor::construct): Tidy code.

--- a/libgui/src/main-window.h
+++ b/libgui/src/main-window.h
@@ -114,10 +114,11 @@
   void debug_step_out ();
   void debug_quit ();
 
+  void read_settings ();
+  void write_settings ();
+
 protected:
   void closeEvent (QCloseEvent * closeEvent);
-  void read_settings ();
-  void write_settings ();
 
 private:
   void construct ();