Build fails with vala 0.54.7

[paper42]

ninja: Entering directory `build'
[1/13] Compiling Vala source ../src/Main.vala ../src/Application.vala ../src/Widgets/Window.vala ../src/Widgets/WelcomePage.vala ../src/Widgets/WelcomeHeaderBar.vala ../src/Widgets/HeaderBar.vala ../src/Widgets/GridUntracked.vala ../src/Widgets/GridStaged.vala ../src/Util/Util.vala ../src/Util/AsyncStatus.vala
FAILED: src/com.github.linarcx.giti.p/Main.c src/com.github.linarcx.giti.p/Application.c src/com.github.linarcx.giti.p/Widgets/Window.c src/com.github.linarcx.giti.p/Widgets/WelcomePage.c src/com.github.linarcx.giti.p/Widgets/WelcomeHeaderBar.c src/com.github.linarcx.giti.p/Widgets/HeaderBar.c src/com.github.linarcx.giti.p/Widgets/GridUntracked.c src/com.github.linarcx.giti.p/Widgets/GridStaged.c src/com.github.linarcx.giti.p/Util/Util.c src/com.github.linarcx.giti.p/Util/AsyncStatus.c 
valac -C --vapidir /builddir/giti-1.0.0/vapi --pkg granite --pkg gee-0.8 --pkg libgit2-glib-1.0 --pkg gtk+-3.0 --color=always --directory src/com.github.linarcx.giti.p --basedir ../src ../src/Main.vala ../src/Application.vala ../src/Widgets/Window.vala ../src/Widgets/WelcomePage.vala ../src/Widgets/WelcomeHeaderBar.vala ../src/Widgets/HeaderBar.vala ../src/Widgets/GridUntracked.vala ../src/Widgets/GridStaged.vala ../src/Util/Util.vala ../src/Util/AsyncStatus.vala
../src/Widgets/GridStaged.vala:28.5-28.36: error: Name `_new_repo' is not valid for a GLib.Object property
    public Ggit.Repository _new_repo { get ; set ; }
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/GridStaged.vala:71.13-71.21: error: invalid left operand
        if( _new_repo == null ){
            ^^^^^^^^^
../src/Widgets/Window.vala:24.9-24.31: error: Name `_stack' is not valid for a GLib.Object property
        public Gtk.Stack _stack { get ; set ; }
        ^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/GridStaged.vala:254.9-254.37: error: The name `add_titled' does not exist in the context of `GITI.Window._stack'
        main_window._stack.add_titled (grid, "staged", "Staged") ;
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/GridUntracked.vala:28.5-28.36: error: Name `_new_repo' is not valid for a GLib.Object property
    public Ggit.Repository _new_repo { get ; set ; }
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/GridUntracked.vala:58.13-58.21: error: invalid left operand
        if( _new_repo == null ){
            ^^^^^^^^^
../src/Widgets/HeaderBar.vala:39.5-39.45: error: Name `_grid_untracked' is not valid for a GLib.Object property
    public GITI.GridUntracked _grid_untracked { get ; set ; }
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/HeaderBar.vala:196.9-196.33: error: The name `load_page' does not exist in the context of `GITI.HeaderBar._grid_untracked'
        _grid_untracked.load_page (_paths[combo.get_active ()]) ;
        ^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/HeaderBar.vala:38.5-38.39: error: Name `_grid_staged' is not valid for a GLib.Object property
    public GITI.GridStaged _grid_staged { get ; set ; }
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/HeaderBar.vala:197.9-197.30: error: The name `load_page' does not exist in the context of `GITI.HeaderBar._grid_staged'
        _grid_staged.load_page (_paths[combo.get_active ()]) ;
        ^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/HeaderBar.vala:35.5-35.40: error: Name `_cb_directories' is not valid for a GLib.Object property
    private Gtk.ComboBox _cb_directories { get ; set ; }
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/HeaderBar.vala:33.5-33.34: error: Name `_current_repo_path' is not valid for a GLib.Object property
    public File _current_repo_path { get ; set ; }
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/HeaderBar.vala:34.5-34.40: error: Name `_current_repo' is not valid for a GLib.Object property
    public Ggit.Repository _current_repo { get ; set ; }
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/Window.vala:28.9-28.45: error: Name `_welcome_page' is not valid for a GLib.Object property
        public GITI.WelcomePage _welcome_page { get ; set ; }
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/WelcomePage.vala:32.17-32.41: error: Invalid type for argument 1
        remove (main_window._welcome_page) ;
                ^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/Window.vala:29.9-29.56: error: Name `_welcome_header_bar' is not valid for a GLib.Object property
        public GITI.WelcomeHeaderBar _welcome_header_bar { get ; set ; }
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/WelcomePage.vala:36.29-36.59: error: Invalid type for argument 1
        main_window.remove (main_window._welcome_header_bar) ;
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Widgets/Window.vala:27.9-27.46: error: Name `_main_header_bar' is not valid for a GLib.Object property
        public GITI.HeaderBar _main_header_bar { get ; set ; }
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../src/Util/AsyncStatus.vala:26.5-26.36: error: Name `_new_repo' is not valid for a GLib.Object property
    public Ggit.Repository _new_repo { get ; set ; }
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Compilation failed: 19 error(s), 0 warning(s)
ninja: build stopped: subcommand failed.

[TaylanTatli]

#3 You can use this PR. It seems project is dead.