Crash while pushing canvas in exceptional circumstances

[Rratic]

script:

using Gtk4
global window::GtkWindow
global topbox::GtkBox
global canvas::GtkCanvas

function init_window_gtk()
    global window = GtkWindow("Test")
    global topbox = GtkBox(:v)
    push!(window, topbox)
    init_menu_gtk()
end

function init_menu_gtk()
    global topbox
    but_create = GtkButton("load")
    signal_connect(but_create, "clicked") do _
        init_canvas_gtk()
    end
    push!(topbox, but_create)
end

function init_canvas_gtk()
    global window
    global topbox
    global canvas = GtkCanvas(100, 100)
    empty!(topbox)
    @guarded draw(canvas) do widget
        ctx = getgc(widget)
        rectangle(ctx, 0, 0, 100, 100)
        set_source_rgb(ctx, 0, 0, 1)
        fill(ctx)
    end
    push!(topbox, canvas)
end

run:

julia> init_window_gtk()
Gtk4.GtkBoxLeaf(accessible-role=GTK_ACCESSIBLE_ROLE_GROUP, orientation=GTK_ORIENTATION_VERTICAL, name="", parent, root, width-request=-1, height-request=-1, visible=true, sensitive=true, can-focus=true, has-focus=false, can-target=true, focus-on-click=true, focusable=false, has-default=false, receives-default=false, cursor, has-tooltip=false, tooltip-markup=nothing, tooltip-text=nothing, opacity=1.000000, overflow=GTK_OVERFLOW_VISIBLE, halign=GTK_ALIGN_FILL, valign=GTK_ALIGN_FILL, margin-start=0, margin-end=0, margin-top=0, margin-bottom=0, hexpand=false, vexpand=false, hexpand-set=false, vexpand-set=false, scale-factor=1, css-name="box", css-classes, layout-manager, spacing=0, homogeneous=false, baseline-position=GTK_BASELINE_POSITION_CENTER)

julia> ┌ Warning: Executing #3:
└ @ Gtk4.GLib C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\signals.jl:116
ERROR: AssertionError: xor(prev, current_task() !== g_stack)
Stacktrace:
  [1] g_siginterruptible(f::Gtk4.GLib.var"#126#128"{Ptr{Gtk4.GLib.GValue}, UInt32, Ptr{Gtk4.GLib.GValue}, Vector{Any}, Gtk4.var"#on_realize#340"{GtkCanvas}}, cb::Any)
    @ Gtk4.GLib C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\signals.jl:212
  [2] GClosureMarshal(closuref::Ptr{Nothing}, return_value::Ptr{Gtk4.GLib.GValue}, n_param_values::UInt32, param_values::Ptr{Gtk4.GLib.GValue}, invocation_hint::Ptr{Nothing}, marshal_data::Ptr{Nothing})
    @ Gtk4.GLib C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\signals.jl:51
  [3] append
    @ C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\gen\gtk4_methods:1166 [inlined]
  [4] push!
    @ C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\layout.jl:31 [inlined]
  [5] init_canvas_gtk()
    @ Main .\REPL[7]:12
  [6] (::var"#3#4")(#unused#::Gtk4.GtkButtonLeaf)
    @ Main .\REPL[6]:5
  [7] (::Gtk4.GLib.var"#126#128"{Ptr{Gtk4.GLib.GValue}, UInt32, Ptr{Gtk4.GLib.GValue}, Vector{Any}, var"#3#4"})()
    @ Gtk4.GLib C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\signals.jl:57
  [8] g_siginterruptible(f::Gtk4.GLib.var"#126#128"{Ptr{Gtk4.GLib.GValue}, UInt32, Ptr{Gtk4.GLib.GValue}, Vector{Any}, var"#3#4"}, cb::Any)
    @ Gtk4.GLib C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\signals.jl:219
  [9] GClosureMarshal(closuref::Ptr{Nothing}, return_value::Ptr{Gtk4.GLib.GValue}, n_param_values::UInt32, param_values::Ptr{Gtk4.GLib.GValue}, invocation_hint::Ptr{Nothing}, marshal_data::Ptr{Nothing})
    @ Gtk4.GLib C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\signals.jl:51
 [10] (::Gtk4.GLib.var"#226#227")()
    @ Gtk4.GLib C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\loop.jl:83
 [11] g_sigatom(f::Any)
    @ Gtk4.GLib C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\signals.jl:186
 [12] glib_main()
    @ Gtk4.GLib C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\loop.jl:80

vscode gives extra message:

Please submit a bug report with steps to reproduce this fault, and any error messages that follow (in their entirety). Thanks.
Exception: EXCEPTION_ACCESS_VIOLATION at 0x67f1de89 -- signal_emit_unlocked_R at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
in expression starting at none:0
signal_emit_unlocked_R at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
g_signal_emit_valist at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
g_signal_emit at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
g_object_dispatch_properties_changed at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
g_object_notify at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
gdk_surface_set_is_mapped at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
gdk_event_translate at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
_gdk_win32_surface_procedure at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
CallWindowProcW at C:\WINDOWS\System32\USER32.dll (unknown line)
CallWindowProcW at C:\WINDOWS\System32\USER32.dll (unknown line)
glPushClientAttrib at C:\WINDOWS\SYSTEM32\OPENGL32.DLL (unknown line)
CallWindowProcW at C:\WINDOWS\System32\USER32.dll (unknown line)
DispatchMessageW at C:\WINDOWS\System32\USER32.dll (unknown line)
LookupIconIdFromDirectoryEx at C:\WINDOWS\System32\USER32.dll (unknown line)
KiUserCallbackDispatcher at C:\WINDOWS\SYSTEM32\ntdll.dll (unknown line)
NtUserShowWindow at C:\WINDOWS\System32\win32u.dll (unknown line)
gdk_surface_hide at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
gtk_window_unmap at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
_g_closure_invoke_va at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
g_signal_emit_valist at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
g_signal_emit at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
gtk_widget_unmap at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
gtk_window_destroy at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
gtk_main_do_event at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
surface_event at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
_gdk_marshal_BOOLEAN__POINTERv at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
gdk_surface_event_marshallerv at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
_g_closure_invoke_va at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
g_signal_emit_valist at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
g_signal_emit at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libgobject-2.0-0.dll (unknown line)
gdk_surface_handle_event at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
gdk_event_dispatch at C:\Users\anonymous\.julia\artifacts\e302132ce205461195ddd4d85b49070d593c8828\bin\libgtk-4-1.dll (unknown line)
g_main_context_dispatch at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libglib-2.0-0.dll (unknown line)
g_main_context_iterate.isra.23 at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libglib-2.0-0.dll (unknown line)
g_main_context_iteration at C:\Users\anonymous\.julia\artifacts\4f67e82ee394e74ca63b7dc589dcc9218c12b20a\bin\libglib-2.0-0.dll (unknown line)
#226 at C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\loop.jl:83
unknown function (ip: 000001cb7b275ee3)
g_sigatom at C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\signals.jl:186
unknown function (ip: 000001cb7b275dd6)
glib_main at C:\Users\anonymous\.julia\packages\Gtk4\NeSVF\src\GLib\loop.jl:80
unknown function (ip: 000001cb7b2751c3)
jl_apply at C:/workdir/src\julia.h:1879 [inlined]
start_task at C:/workdir/src\task.c:1092
Allocations: 10449099 (Pool: 10440476; Big: 8623); GC: 15

environment:

julia> versioninfo()
Julia Version 1.9.1
Commit 147bdf428c (2023-06-07 08:27 UTC)
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: 8 × Intel(R) Core(TM) i5-10210U CPU @ 1.60GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-14.0.6 (ORCJIT, skylake)
  Threads: 1 on 8 virtual cores

(@v1.9) pkg> st Gtk4
Status `C:\Users\anonymous\.julia\environments\v1.9\Project.toml`
  [9db2cae5] Gtk4 v0.4.1

[jwahlstrand]

Confirmed on Linux. The code works if I use

@idle_add init_canvas_gtk()

in the "clicked" callback instead of just init_canvas_gtk().

[Rratic]

This works.

So shall I use @idle_add in every signal_connect in case of crash? If not, when shall I use it?

[tknopp]

So shall I use @idle_add in every signal_connect in case of crash?

yes. When you are in a callback, always call @idle_add in case you are modifying the UI. In your case the empty!(topbox) call is modifying the UI.

@jwahlstrand: I am closing this one. If you see this as a bug, please re-open.