[gnome-tetravex] Use --enable-experimental-non-null.

[Arnaud B. <arnaudb src gnome org>]

commit 975b080b5511a48d0b38fc46a29b9baf61c2484d
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Tue Sep 17 06:36:42 2019 +0200

    Use --enable-experimental-non-null.

 src/gnome-tetravex.vala | 77 +++++++++++++++++++++++++++++++++++--------------
 src/history.vala        |  2 +-
 src/meson.build         |  3 +-
 src/puzzle-view.vala    | 51 +++++++++++++++++---------------
 src/puzzle.vala         | 41 +++++++++++++-------------
 src/score-dialog.vala   |  2 +-
 src/theme.vala          |  2 +-
 7 files changed, 109 insertions(+), 69 deletions(-)
---
diff --git a/src/gnome-tetravex.vala b/src/gnome-tetravex.vala
index 39ae451..b27e2e3 100644
--- a/src/gnome-tetravex.vala
+++ b/src/gnome-tetravex.vala
@@ -13,6 +13,9 @@ using Gtk;
 
 private class Tetravex : Gtk.Application
 {
+    /* Translators: that is the name of the program, as seen in the headerbar, in GNOME Shell, or in the 
about dialog */
+    private const string PROGRAM_NAME = _("Tetravex");
+
     private const string KEY_GRID_SIZE = "grid-size";
 
     private static bool start_paused = false;
@@ -21,6 +24,7 @@ private class Tetravex : Gtk.Application
     private GLib.Settings settings;
 
     private Puzzle puzzle;
+    private bool puzzle_init_done = false;
     private Label clock_label;
     private History history;
 
@@ -38,12 +42,12 @@ private class Tetravex : Gtk.Application
     private SimpleAction pause_action;
     private SimpleAction solve_action;
 
-    private const OptionEntry[] option_entries =
+    private const OptionEntry [] option_entries =
     {
         { "version", 'v', 0, OptionArg.NONE, null, N_("Print release version and exit"), null },
         { "paused", 'p', 0, OptionArg.NONE, null, N_("Start the game paused"), null },
         { "size", 's', 0, OptionArg.INT, null, N_("Set size of board (2-6)"), null },
-        { null }
+        {}
     };
 
     private const GLib.ActionEntry[] action_entries =
@@ -84,7 +88,7 @@ private class Tetravex : Gtk.Application
     {
         base.startup ();
 
-        Environment.set_application_name (_("Tetravex"));
+        Environment.set_application_name (PROGRAM_NAME);
         Window.set_default_icon_name ("org.gnome.Tetravex");
 
         add_action_entries (action_entries, this);
@@ -120,7 +124,7 @@ private class Tetravex : Gtk.Application
         ((SimpleAction) lookup_action ("size")).set_state ("%d".printf (game_size));
 
         HeaderBar headerbar = new HeaderBar ();
-        headerbar.title = _("Tetravex");
+        headerbar.title = PROGRAM_NAME;
         headerbar.show_close_button = true;
         window.set_titlebar (headerbar);
 
@@ -214,7 +218,9 @@ private class Tetravex : Gtk.Application
         pause_action = (SimpleAction) lookup_action ("pause");
         solve_action = (SimpleAction) lookup_action ("solve");
         view.tile_selected.connect ((/* bool */ selected) => {
-                if (puzzle == null || ((!) puzzle).is_solved)
+                if (!puzzle_init_done)
+                    return;
+                if (puzzle.is_solved)
                     return;
                 solve_action.set_enabled (!selected);
             });
@@ -289,11 +295,12 @@ private class Tetravex : Gtk.Application
         solve_action.set_enabled (true);
         new_game_solve_stack.set_visible_child_name ("solve");
 
-        if (puzzle != null)
+        if (puzzle_init_done)
             SignalHandler.disconnect_by_func (puzzle, null, this);
 
         int size = settings.get_int (KEY_GRID_SIZE);
         puzzle = new Puzzle ((uint8) size);
+        puzzle_init_done = true;
         puzzle.tick.connect (tick_cb);
         puzzle.solved.connect (solved_cb);
         view.puzzle = puzzle;
@@ -310,7 +317,7 @@ private class Tetravex : Gtk.Application
     private void tick_cb ()
     {
         int elapsed = 0;
-        if (puzzle != null)
+        if (puzzle_init_done)
             elapsed = (int) (puzzle.elapsed + 0.5);
         int hours = elapsed / 3600;
         int minutes = (elapsed - hours * 3600) / 60;
@@ -417,22 +424,48 @@ private class Tetravex : Gtk.Application
 
     private void about_cb ()
     {
-        string[] authors = { "Lars Rydlinge", "Robert Ancell", null };
-        string[] documenters = { "Rob Bradford", null };
+        string [] authors = {
+        /* Translators: text crediting a game author, seen in the About dialog */
+            _("Lars Rydlinge"),
+
+
+        /* Translators: text crediting a game author, seen in the About dialog */
+            _("Robert Ancell")
+        };
+
+        /* Translators: text crediting a game documenter, seen in the About dialog */
+        string [] documenters = { _("Rob Bradford") };
+
+
+        /* Translators: short description of the application, seen in the About dialog */
+        string comments = _("Position pieces so that the same numbers are touching each other");
+
+
+        /* Translators: text crediting a maintainer, seen in the About dialog; the %u are replaced with the 
years of start and end */
+        string copyright = _("Copyright \xc2\xa9 %u-%u – Lars Rydlinge").printf (1999, 2008) + "\n" +
+
+
+        /* Translators: text crediting a maintainer, seen in the About dialog; the %u are replaced with the 
years of start and end */
+                           _("Copyright \xc2\xa9 %u-%u – Arnaud Bonatti").printf (2019, 2020);
+
+
+        /* Translators: about dialog text; label of the website link */
+        string website_label = _("Page on GNOME wiki");
+
         show_about_dialog (window,
-                           "program-name", _("Tetravex"),
-                           "version", VERSION,
-                           "comments",
-                           _("Position pieces so that the same numbers are touching each other"),
-                           "copyright",
-                           "Copyright © 1999–2008 Lars Rydlinge",
-                           "license-type", License.GPL_2_0,
-                           "wrap-license", true,
-                           "authors", authors,
-                           "documenters", documenters,
-                           "translator-credits", _("translator-credits"),
-                           "logo-icon-name", "org.gnome.Tetravex",
-                           "website", "https://wiki.gnome.org/Apps/Tetravex";,
+                           "program-name",          PROGRAM_NAME,
+                           "version",               VERSION,
+                           "comments",              comments,
+                           "copyright",             copyright,
+                           "license-type",          License.GPL_2_0,
+                           "wrap-license",          true,
+                           "authors",               authors,
+                           "documenters",           documenters,
+        /* Translators: about dialog text; this string should be replaced by a text crediting yourselves and 
your translation team, or should be left empty. Do not translate literally! */
+                           "translator-credits",    _("translator-credits"),
+                           "logo-icon-name",        "org.gnome.Tetravex",
+                           "website",               "https://wiki.gnome.org/Apps/Tetravex";,
+                           "website-label",         website_label,
                            null);
     }
 
diff --git a/src/history.vala b/src/history.vala
index 4d88dda..822df20 100644
--- a/src/history.vala
+++ b/src/history.vala
@@ -57,7 +57,7 @@ private class History : Object
 
             // FIXME use try_parse
 
-            add (new HistoryEntry (date, size, duration));
+            add (new HistoryEntry ((!) date, size, duration));
         }
     }
 
diff --git a/src/meson.build b/src/meson.build
index 2b258f8..5aaf72b 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -13,7 +13,8 @@ gnome_tetravex = executable ('gnome-tetravex',
                              dependencies: [ glib_dep,
                                              gtk_dep,
                                              libm_dep ],
-                             vala_args: [ '--pkg=posix' ],
+                             vala_args: [ '--pkg=posix',
+                                          '--enable-experimental-non-null' ],
                              c_args: [ '-DVERSION="@0@"'.format (meson.project_version ()),
                                        '-DGETTEXT_PACKAGE="gnome-tetravex"',
                                        '-DLOCALEDIR="@0@"'.format (localedir) ],
diff --git a/src/puzzle-view.vala b/src/puzzle-view.vala
index 5db3a3d..dcf1f7d 100644
--- a/src/puzzle-view.vala
+++ b/src/puzzle-view.vala
@@ -45,31 +45,32 @@ private class PuzzleView : Gtk.DrawingArea
 
     /* Puzzle being rendered */
     private Puzzle? _puzzle = null;
+    [CCode (notify = false)] private bool puzzle_init_done { get { return _puzzle != null; }}
     [CCode (notify = false)] internal Puzzle puzzle
     {
-        private get { return _puzzle; }
+        private get { if (!puzzle_init_done) assert_not_reached (); return (!) _puzzle; }
         internal set
         {
-            if (_puzzle != null)
-                SignalHandler.disconnect_by_func (_puzzle, null, this);
+            if (puzzle_init_done)
+                SignalHandler.disconnect_by_func ((!) _puzzle, null, this);
 
             _puzzle = value;
             tiles.remove_all ();
-            for (uint8 y = 0; y < puzzle.size; y++)
+            for (uint8 y = 0; y < ((!) _puzzle).size; y++)
             {
-                for (uint8 x = 0; x < puzzle.size * 2; x++)
+                for (uint8 x = 0; x < ((!) _puzzle).size * 2; x++)
                 {
-                    Tile? tile = puzzle.get_tile (x, y);
+                    Tile? tile = ((!) _puzzle).get_tile (x, y);
                     if (tile == null)
                         continue;
 
-                    TileImage image = new TileImage (tile);
+                    TileImage image = new TileImage ((!) tile);
                     move_tile_to_location (image, x, y);
-                    tiles.insert (tile, image);
+                    tiles.insert ((!) tile, image);
                 }
             }
-            _puzzle.tile_moved.connect (tile_moved_cb);
-            _puzzle.notify ["paused"].connect (() => { queue_draw (); });
+            ((!) _puzzle).tile_moved.connect (tile_moved_cb);
+            ((!) _puzzle).notify ["paused"].connect (() => { queue_draw (); });
             queue_resize ();
         }
     }
@@ -222,7 +223,7 @@ private class PuzzleView : Gtk.DrawingArea
     protected override void get_preferred_width (out int minimum, out int natural)
     {
         int size = 0;
-        if (puzzle != null)
+        if (puzzle_init_done)
             size = (int) ((puzzle.size * 2 + 1.5) * minimum_size);
         minimum = natural = int.max (size, 500);
     }
@@ -230,7 +231,7 @@ private class PuzzleView : Gtk.DrawingArea
     protected override void get_preferred_height (out int minimum, out int natural)
     {
         int size = 0;
-        if (puzzle != null)
+        if (puzzle_init_done)
             size = (int) ((puzzle.size + 1) * minimum_size);
         minimum = natural = int.max (size, 300);
     }
@@ -273,7 +274,7 @@ private class PuzzleView : Gtk.DrawingArea
 
     protected override bool draw (Cairo.Context context)
     {
-        if (puzzle == null)
+        if (!puzzle_init_done)
             return false;
 
         uint x_offset, y_offset, size, gap;
@@ -312,7 +313,9 @@ private class PuzzleView : Gtk.DrawingArea
             if (!iter.next (out tile, out image))
                 break;
 
-            if (image == selected_tile || image.x != image.target_x || image.y != image.target_y)
+            if ((selected_tile != null && image == (!) selected_tile)
+             || (image.x != image.target_x)
+             || (image.y != image.target_y))
                 continue;
 
             context.save ();
@@ -333,7 +336,9 @@ private class PuzzleView : Gtk.DrawingArea
             if (!iter.next (out tile, out image))
                 break;
 
-            if (image != selected_tile && image.x == image.target_x && image.y == image.target_y)
+            if ((selected_tile != null && image != (!) selected_tile)
+             && (image.x == image.target_x)
+             && (image.y == image.target_y))
                 continue;
 
             context.save ();
@@ -442,16 +447,16 @@ private class PuzzleView : Gtk.DrawingArea
 
         /* Drop the tile here, or move it back if can't */
         uint8 selected_x, selected_y;
-        puzzle.get_tile_location (selected_tile.tile, out selected_x, out selected_y);
+        puzzle.get_tile_location (((!) selected_tile).tile, out selected_x, out selected_y);
         if (puzzle.can_switch (selected_x, selected_y, (uint8) tile_x, (uint8) tile_y))
             puzzle.switch_tiles (selected_x, selected_y, (uint8) tile_x, (uint8) tile_y);
         else
-            move_tile_to_location (selected_tile, selected_x, selected_y, 0.2);
+            move_tile_to_location ((!) selected_tile, selected_x, selected_y, 0.2);
         selected_tile = null;
         tile_selected (false);
     }
 
-    private void move_tile_to_right_half (TileImage image)
+    private void move_tile_to_right_half (Tile tile)
     {
         /* Pick the first open spot on the right side of the board */
         for (uint8 y = 0; y < puzzle.size; y++)
@@ -461,7 +466,7 @@ private class PuzzleView : Gtk.DrawingArea
                 if (puzzle.get_tile (x, y) == null)
                 {
                     uint8 source_x, source_y;
-                    puzzle.get_tile_location (image.tile, out source_x, out source_y);
+                    puzzle.get_tile_location (tile, out source_x, out source_y);
                     puzzle.switch_tiles (source_x, source_y, x, y);
                     return;
                 }
@@ -481,15 +486,15 @@ private class PuzzleView : Gtk.DrawingArea
             {
                 if (selected_tile == null)
                     pick_tile (event.x, event.y);
-                else if (selected_tile != null)
+                else
                     drop_tile (event.x, event.y);
             }
             else if (event.type == Gdk.EventType.DOUBLE_BUTTON_PRESS)
             {
                 /* Move tile from left to right on double click */
                 pick_tile (event.x, event.y);
-                if (selected_tile != null && !on_right_half (selected_tile.x))
-                    move_tile_to_right_half (selected_tile);
+                if (selected_tile != null && !on_right_half (((!) selected_tile).x))
+                    move_tile_to_right_half (((!) selected_tile).tile);
                 selected_tile = null;
                 tile_selected (false);
             }
@@ -516,7 +521,7 @@ private class PuzzleView : Gtk.DrawingArea
     protected override bool motion_notify_event (Gdk.EventMotion event)
     {
         if (selected_tile != null)
-            move_tile (selected_tile, (int) (event.x - selected_x_offset), (int) (event.y - 
selected_y_offset));
+            move_tile ((!) selected_tile, (int) (event.x - selected_x_offset), (int) (event.y - 
selected_y_offset));
 
         return false;
     }
diff --git a/src/puzzle.vala b/src/puzzle.vala
index 5b7805c..05f9f0c 100644
--- a/src/puzzle.vala
+++ b/src/puzzle.vala
@@ -30,7 +30,7 @@ private class Tile : Object
 private class Puzzle : Object
 {
     [CCode (notify = false)] public uint8 size { internal get; protected construct; }
-    private Tile [,] board;
+    private Tile? [,] board;
 
     /* Game timer */
     private double clock_elapsed;
@@ -43,7 +43,7 @@ private class Puzzle : Object
         {
             if (clock == null)
                 return 0.0;
-            return clock_elapsed + clock.elapsed ();
+            return clock_elapsed + ((!) clock).elapsed ();
         }
     }
 
@@ -95,7 +95,7 @@ private class Puzzle : Object
 
     construct
     {
-        board = new Tile [size * 2, size];
+        board = new Tile? [size * 2, size];
         for (uint8 x = 0; x < size; x++)
             for (uint8 y = 0; y < size; y++)
                 board [x, y] = new Tile (x, y);
@@ -107,9 +107,9 @@ private class Puzzle : Object
             {
                 uint8 n = (uint8) Random.int_range (0, 10);
                 if (y >= 1)
-                    board [x, y - 1].south = n;
+                    ((!) board [x, y - 1]).south = n;
                 if (y < size)
-                    board [x, y].north = n;
+                    ((!) board [x, y]).north = n;
             }
         }
         for (uint8 x = 0; x <= size; x++)
@@ -118,9 +118,9 @@ private class Puzzle : Object
             {
                 uint8 n = (uint8) Random.int_range (0, 10);
                 if (x >= 1)
-                    board [x - 1, y].east = n;
+                    ((!) board [x - 1, y]).east = n;
                 if (x < size)
-                    board [x, y].west = n;
+                    ((!) board [x, y]).west = n;
             }
         }
 
@@ -130,7 +130,7 @@ private class Puzzle : Object
         {
             for (uint8 y = 0; y < size; y++)
             {
-                tiles.append (board [x, y]);
+                tiles.append ((!) board [x, y]);
                 board [x, y] = null;
             }
         }
@@ -170,13 +170,13 @@ private class Puzzle : Object
         if (tile == null)
             return false;
 
-        if (x1 > 0 && !(x1 - 1 == x0 && y1 == y0) && board [x1 - 1, y1] != null && board [x1 - 1, y1].east 
!= tile.west)
+        if (x1 > 0 && !(x1 - 1 == x0 && y1 == y0) && board [x1 - 1, y1] != null && ((!) board [x1 - 1, 
y1]).east != ((!) tile).west)
             return false;
-        if (x1 < size - 1 && !(x1 + 1 == x0 && y1 == y0) && board [x1 + 1, y1] != null && board [x1 + 1, 
y1].west != tile.east)
+        if (x1 < size - 1 && !(x1 + 1 == x0 && y1 == y0) && board [x1 + 1, y1] != null && ((!) board [x1 + 
1, y1]).west != ((!) tile).east)
             return false;
-        if (y1 > 0 && !(x1 == x0 && y1 - 1 == y0) && board [x1, y1 - 1] != null && board [x1, y1 - 1].south 
!= tile.north)
+        if (y1 > 0 && !(x1 == x0 && y1 - 1 == y0) && board [x1, y1 - 1] != null && ((!) board [x1, y1 - 
1]).south != ((!) tile).north)
             return false;
-        if (y1 < size - 1 && !(x1 == x0 && y1 + 1 == y0) && board [x1, y1 + 1] != null && board [x1, y1 + 
1].north != tile.south)
+        if (y1 < size - 1 && !(x1 == x0 && y1 + 1 == y0) && board [x1, y1 + 1] != null && ((!) board [x1, y1 
+ 1]).north != ((!) tile).south)
             return false;
 
         return true;
@@ -214,9 +214,9 @@ private class Puzzle : Object
         board [x1, y1] = t0;
 
         if (t0 != null)
-            tile_moved (t0, x1, y1);
+            tile_moved ((!) t0, x1, y1);
         if (t1 != null)
-            tile_moved (t1, x0, y0);
+            tile_moved ((!) t1, x0, y0);
 
         if (is_solved)
         {
@@ -303,14 +303,14 @@ private class Puzzle : Object
 
     internal void solve ()
     {
-        List<Tile> wrong_tiles = null;
+        List<Tile> wrong_tiles = new List<Tile> ();
         for (uint8 x = 0; x < size * 2; x++)
         {
             for (uint8 y = 0; y < size; y++)
             {
                 Tile? tile = board [x, y];
-                if (tile != null && (tile.x != x || tile.y != y))
-                    wrong_tiles.append (tile);
+                if (tile != null && (((!) tile).x != x || ((!) tile).y != y))
+                    wrong_tiles.append ((!) tile);
                 board [x, y] = null;
             }
         }
@@ -342,7 +342,7 @@ private class Puzzle : Object
         if (clock_timeout != 0)
             Source.remove (clock_timeout);
         clock_timeout = 0;
-        clock.stop ();
+        ((!) clock).stop ();
         tick ();
     }
 
@@ -351,14 +351,15 @@ private class Puzzle : Object
         if (clock == null)
             clock = new Timer ();
         else
-            clock.@continue ();
+            ((!) clock).@continue ();
         timeout_cb ();
     }
 
     private bool timeout_cb ()
+        requires (clock != null)
     {
         /* Notify on the next tick */
-        double elapsed = clock.elapsed ();
+        double elapsed = ((!) clock).elapsed ();
         int next = (int) (elapsed + 1.0);
         double wait = (double) next - elapsed;
         clock_timeout = Timeout.add ((int) (wait * 1000), timeout_cb);
diff --git a/src/score-dialog.vala b/src/score-dialog.vala
index 31d219e..8bbccc3 100644
--- a/src/score-dialog.vala
+++ b/src/score-dialog.vala
@@ -172,7 +172,7 @@ private class ScoreDialog : Gtk.Dialog
                 size_combo.set_active_iter (iter);
 
             /* Select this entry if the same category as the selected one */
-            if (selected_entry != null && entry.size == selected_entry.size)
+            if (selected_entry != null && entry.size == ((!) selected_entry).size)
                 size_combo.set_active_iter (iter);
         }
     }
diff --git a/src/theme.vala b/src/theme.vala
index b2c404d..cb3291d 100644
--- a/src/theme.vala
+++ b/src/theme.vala
@@ -137,7 +137,7 @@ private class Theme : Object
         draw_tile_background (context, size, paused_color, paused_color, paused_color, paused_color);
     }
 
-    internal void draw_tile (Cairo.Context context, uint size, Tile? tile)
+    internal void draw_tile (Cairo.Context context, uint size, Tile tile)
     {
         draw_tile_background (context, size, tile_colors [tile.north], tile_colors [tile.east], tile_colors 
[tile.south], tile_colors [tile.west]);