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[Gtk3] Bug: SWTException on Table.remove(...) for a row with focus #1606

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om-11-2024 opened this issue Nov 21, 2024 · 0 comments · May be fixed by #1608
Open

[Gtk3] Bug: SWTException on Table.remove(...) for a row with focus #1606

om-11-2024 opened this issue Nov 21, 2024 · 0 comments · May be fixed by #1608

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@om-11-2024
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Describe the bug
SWTException on Table.remove(...) for a row with focus.

To Reproduce
A standalone SWT snippet to reproduce the behavior:

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class SwtBugSnippet {

  public static void main( String[] args ) {
    var display = Display.getDefault();
    var shell = new Shell( display );
    shell.setLayout( new GridLayout() );

    var button = new Button( shell, SWT.PUSH );
    button.setText( "GO" );

    var table = new Table( shell, SWT.VIRTUAL );
    var layoutData = new GridData( 300, 300 );
    layoutData.grabExcessHorizontalSpace = layoutData.grabExcessVerticalSpace = true;
    table.setLayoutData( layoutData );
    table.setItemCount( 2 );
    table.addListener( SWT.SetData, event -> {
      var item = ( TableItem ) event.item;
      item.setText( "Item #" + System.identityHashCode( item ) );
    } );

    shell.pack();
    shell.open();

    table.setFocus();

    button.addListener( SWT.Selection, e -> {
      table.clear( 0 );
      table.remove( new int[] { 0 } );
    } );

    while ( !shell.isDisposed() ) {
      if ( !display.readAndDispatch() ) {
        display.sleep();
      }
    }
  }
}

Just press the "GO" button and the program terminates after printing this to stderr:

Exception in thread "main" org.eclipse.swt.SWTException: Widget is disposed
	at org.eclipse.swt.SWT.error(SWT.java:4922)
	at org.eclipse.swt.SWT.error(SWT.java:4837)
	at org.eclipse.swt.SWT.error(SWT.java:4808)
	at org.eclipse.swt.widgets.Widget.error(Widget.java:565)
	at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:480)
	at org.eclipse.swt.widgets.TableItem.setText(TableItem.java:1363)
	at SwtBugSnippet.lambda$0(SwtBugSnippet.java:24)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5855)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1529)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1555)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1538)
	at org.eclipse.swt.widgets.Table.checkData(Table.java:289)
	at org.eclipse.swt.widgets.Table.cellDataProc(Table.java:227)
	at org.eclipse.swt.widgets.Display.cellDataProc(Display.java:995)
	at org.eclipse.swt.internal.gtk.GTK.gtk_list_store_remove(Native Method)
	at org.eclipse.swt.widgets.Table.remove(Table.java:2772)
	at SwtBugSnippet.lambda$1(SwtBugSnippet.java:34)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5855)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1529)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:5065)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:4517)
	at SwtBugSnippet.main(SwtBugSnippet.java:38)

Expected behavior
The row should be successfully removed without errors.

Screenshots
Not applicable.

Environment:

  1. Select the platform(s) on which the behavior is seen:
    • All OS
    • Windows
    • Linux
    • macOS

  1. Additional OS info (e.g. OS version, Linux Desktop, etc)
    Os: Ubuntu 24.04.1 LTS
    Xfce: 4.18
    Gtk: 3.24.41
    Swt: 4.967.8

  2. JRE/JDK version
    OpenJDK 64-Bit Server VM (build 17.0.12+7-Ubuntu-1ubuntu224.04, mixed mode, sharing)

Version since
at least since Swt 4.967.8

Workaround (or) Additional context
I will submit a pull request with a fix a little bit later.
om-11-2024 added a commit to om-11-2024/eclipse.platform.swt that referenced this issue Nov 21, 2024
@om-11-2024
[Gtk3] fix for SWTException on Table.remove(...) with focused row ecl…
b723191 
…ipse-platform#1606

Fix for SWTException on Table.remove(...) with focused row.
This bug happens only in Gtk3.
Cause: `gtk_list_store_remove(...)` for a focused row invokes `Table.cellDataProc(...)` with not-yet-updated `Table.items`.
Fix: remove `TableItem` from `Table.items` before `gtk_list_store_remove(...)`.

Fixes eclipse-platform#1606:

The exception only happens in Gtk3.

Java stacktrace:
```java
org.eclipse.swt.SWTException: Widget is disposed
	at org.eclipse.swt.SWT.error(SWT.java:4922)
	at org.eclipse.swt.SWT.error(SWT.java:4837)
	at org.eclipse.swt.SWT.error(SWT.java:4808)
	at org.eclipse.swt.widgets.Widget.error(Widget.java:597)
	at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:512)
	at org.eclipse.swt.widgets.TableItem.setText(TableItem.java:1363)
	at org.eclipse.swt.tests.gtk.Test_Gtk3_Table_Remove_Focused_Row.lambda$3(Test_Gtk3_Table_Remove_Focused_Row.java:68)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:91)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5857)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1617)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1643)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1626)
	at org.eclipse.swt.widgets.Table.checkData(Table.java:289)
	at org.eclipse.swt.widgets.Table.cellDataProc(Table.java:227)
	at org.eclipse.swt.widgets.Display.cellDataProc(Display.java:995)
	at org.eclipse.swt.internal.gtk.GTK.gtk_list_store_remove(Native Method)
	at org.eclipse.swt.widgets.Table.remove(Table.java:2668)
	...
```

The main cause of the error is that:
 1. when a row with focus is deleted with `gtk_list_store_remove(...)`, then cell data function `Table.cellDataProc(...)` is called for a row after the removed one
 2. but inside `Table.cellDataProc(...)` `Table.items` isn't yet updated , therefore `Table.cellDataProc(...)` operates with `TableItem`, which is already disposed but not yet removed from `Table.items`

Inside `gtk_list_store_remove(...)` the row is removed from the `GtkTreeModel`, and only then `GtkTreeView` callbacks are invoked.
It means that when `Table.cellDataProc(...)` is invoked, the row has already been removed in Gtk3.

The fix: remove `TableItem` from `Table.items` before `gtk_list_store_remove(...)` instead of after.

Important: I haven't tried to reproduce this bug in GTK4.

Os:  Ubuntu 24.04.1 LTS
Gtk: 3.24.41
Swt: 4.967.8

=================================================

Why `gtk_list_store_remove(...)` invokes `Table.cellDataProc(...)` only for a row with focus and not for ordinary rows?

The reason is that in gtk3 when a row with focus is deleted, the next row receives focus, which among other things creates `GtkCellAccessible` (a "cell with focus" for assistive technology in gtk3).
Creation of `GtkCellAccessible` invokes cell data function `Table.cellDataProc(...)` - just like it happens when a standard cell in `GtkTreeView` gets rendered.

Here is the stacktrace in gtk3 code:
```c
apply_cell_attributes() at gtkcellarea.c:1257
g_hash_table_foreach() at ghash.c:2117
gtk_cell_area_real_apply_attributes() at gtkcellarea.c:1286
gtk_cell_area_box_apply_attributes() at gtkcellareabox.c:1310
_gtk_marshal_VOID__OBJECT_BOXED_BOOLEAN_BOOLEANv() at gtkmarshalers.c:5447
g_type_class_meta_marshalv() at gclosure.c:1062
_g_closure_invoke_va() at gclosure.c:897
signal_emit_valist_unlocked() at gsignal.c:3424
g_signal_emit_valist() at gsignal.c:3263
g_signal_emit() at gsignal.c:3583
gtk_cell_area_apply_attributes() at gtkcellarea.c:2373
gtk_tree_view_column_cell_set_cell_data() at gtktreeviewcolumn.c:2821
set_cell_data() at gtktreeviewaccessible.c:347
create_cell() at gtktreeviewaccessible.c:439
_gtk_tree_view_accessible_add_state() at gtktreeviewaccessible.c:2053
gtk_tree_view_real_set_cursor() at gtktreeview.c:13377
gtk_tree_view_row_deleted() at gtktreeview.c:9430
g_cclosure_marshal_VOID__BOXED() at gmarshal.c:1628
g_closure_invoke() at gclosure.c:834
signal_emit_unlocked_R() at gsignal.c:3888
signal_emit_valist_unlocked() at gsignal.c:3520
g_signal_emit_valist() at gsignal.c:3263
g_signal_emit() at gsignal.c:3583
gtk_tree_model_row_deleted() at gtktreemodel.c:1914
gtk_list_store_remove() at gtkliststore.c:1219
Java_org_eclipse_swt_internal_gtk_GTK_gtk_1list_1store_1remove()
```

The code that leads to execution of cell data function for a row with focus is in gtktreeview.c:
```
static void
gtk_tree_view_row_deleted (GtkTreeModel *model,
			   GtkTreePath  *path,
			   gpointer      data)
{
  ...
  /* If the cursor row got deleted, move the cursor to the next row */
  if (tree_view->priv->cursor_node &&
      (tree_view->priv->cursor_node == node ||
       (node->children && (tree_view->priv->cursor_tree == node->children ||
                           _gtk_rbtree_contains (node->children, tree_view->priv->cursor_tree)))))
    {
      ...
      cursor_changed = TRUE;
    }
  ...
  if (cursor_changed)
    {
      if (cursor_node)
        {
          ...
          gtk_tree_view_real_set_cursor (tree_view, cursor_path, CLEAR_AND_SELECT | CURSOR_INVALID);
          ...
        }
      ...
    }
  ...
}
```
om-11-2024 added a commit to om-11-2024/eclipse.platform.swt that referenced this issue Nov 21, 2024
@om-11-2024
[Gtk3] fix for SWTException on Table.remove(...) with focused row ecl…
9d5b707 
…ipse-platform#1606

Fix for `SWTException` on `Table.remove(...)` with focused row.
This bug happens only in Gtk3.
Cause: `gtk_list_store_remove(...)` for a focused row invokes `Table.cellDataProc(...)` with not-yet-updated `Table.items`.
Fix: remove `TableItem` from `Table.items` before `gtk_list_store_remove(...)`.

Fixes eclipse-platform#1606:

The exception only happens in Gtk3.

Java stacktrace:
```java
org.eclipse.swt.SWTException: Widget is disposed
	at org.eclipse.swt.SWT.error(SWT.java:4922)
	at org.eclipse.swt.SWT.error(SWT.java:4837)
	at org.eclipse.swt.SWT.error(SWT.java:4808)
	at org.eclipse.swt.widgets.Widget.error(Widget.java:597)
	at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:512)
	at org.eclipse.swt.widgets.TableItem.setText(TableItem.java:1363)
	at org.eclipse.swt.tests.gtk.Test_Gtk3_Table_Remove_Focused_Row.lambda$3(Test_Gtk3_Table_Remove_Focused_Row.java:68)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:91)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5857)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1617)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1643)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1626)
	at org.eclipse.swt.widgets.Table.checkData(Table.java:289)
	at org.eclipse.swt.widgets.Table.cellDataProc(Table.java:227)
	at org.eclipse.swt.widgets.Display.cellDataProc(Display.java:995)
	at org.eclipse.swt.internal.gtk.GTK.gtk_list_store_remove(Native Method)
	at org.eclipse.swt.widgets.Table.remove(Table.java:2668)
	...
```

The main cause of the error is that:
 1. when a row with focus is deleted with `gtk_list_store_remove(...)`, then cell data function `Table.cellDataProc(...)` is called for a row after the removed one
 2. but inside `Table.cellDataProc(...)` `Table.items` isn't yet updated , therefore `Table.cellDataProc(...)` operates with `TableItem`, which is already disposed but not yet removed from `Table.items`

Inside `gtk_list_store_remove(...)` the row is removed from the `GtkTreeModel`, and only then `GtkTreeView` callbacks are invoked.
It means that when `Table.cellDataProc(...)` is invoked, the row has already been removed in Gtk3.

The fix: remove `TableItem` from `Table.items` before `gtk_list_store_remove(...)` instead of after.

Important: I haven't tried to reproduce this bug in GTK4.

Os:  Ubuntu 24.04.1 LTS
Gtk: 3.24.41
Swt: 4.967.8

=================================================

Why `gtk_list_store_remove(...)` invokes `Table.cellDataProc(...)` only for a row with focus and not for ordinary rows?

The reason is that in gtk3 when a row with focus is deleted, the next row receives focus, which among other things creates `GtkCellAccessible` (a "cell with focus" for assistive technology in gtk3).
Creation of `GtkCellAccessible` invokes cell data function `Table.cellDataProc(...)` - just like it happens when a standard cell in `GtkTreeView` gets rendered.

Here is the stacktrace in gtk3 code:
```c
apply_cell_attributes() at gtkcellarea.c:1257
g_hash_table_foreach() at ghash.c:2117
gtk_cell_area_real_apply_attributes() at gtkcellarea.c:1286
gtk_cell_area_box_apply_attributes() at gtkcellareabox.c:1310
_gtk_marshal_VOID__OBJECT_BOXED_BOOLEAN_BOOLEANv() at gtkmarshalers.c:5447
g_type_class_meta_marshalv() at gclosure.c:1062
_g_closure_invoke_va() at gclosure.c:897
signal_emit_valist_unlocked() at gsignal.c:3424
g_signal_emit_valist() at gsignal.c:3263
g_signal_emit() at gsignal.c:3583
gtk_cell_area_apply_attributes() at gtkcellarea.c:2373
gtk_tree_view_column_cell_set_cell_data() at gtktreeviewcolumn.c:2821
set_cell_data() at gtktreeviewaccessible.c:347
create_cell() at gtktreeviewaccessible.c:439
_gtk_tree_view_accessible_add_state() at gtktreeviewaccessible.c:2053
gtk_tree_view_real_set_cursor() at gtktreeview.c:13377
gtk_tree_view_row_deleted() at gtktreeview.c:9430
g_cclosure_marshal_VOID__BOXED() at gmarshal.c:1628
g_closure_invoke() at gclosure.c:834
signal_emit_unlocked_R() at gsignal.c:3888
signal_emit_valist_unlocked() at gsignal.c:3520
g_signal_emit_valist() at gsignal.c:3263
g_signal_emit() at gsignal.c:3583
gtk_tree_model_row_deleted() at gtktreemodel.c:1914
gtk_list_store_remove() at gtkliststore.c:1219
Java_org_eclipse_swt_internal_gtk_GTK_gtk_1list_1store_1remove()
```

The code that leads to execution of cell data function for a row with focus is in gtktreeview.c:
```
static void
gtk_tree_view_row_deleted (GtkTreeModel *model,
			   GtkTreePath  *path,
			   gpointer      data)
{
  ...
  /* If the cursor row got deleted, move the cursor to the next row */
  if (tree_view->priv->cursor_node &&
      (tree_view->priv->cursor_node == node ||
       (node->children && (tree_view->priv->cursor_tree == node->children ||
                           _gtk_rbtree_contains (node->children, tree_view->priv->cursor_tree)))))
    {
      ...
      cursor_changed = TRUE;
    }
  ...
  if (cursor_changed)
    {
      if (cursor_node)
        {
          ...
          gtk_tree_view_real_set_cursor (tree_view, cursor_path, CLEAR_AND_SELECT | CURSOR_INVALID);
          ...
        }
      ...
    }
  ...
}
```
om-11-2024 added a commit to om-11-2024/eclipse.platform.swt that referenced this issue Nov 21, 2024
@om-11-2024
[Gtk3] fix for SWTException on Table.remove(...) with focused row ecl…
b48723f 
…ipse-platform#1606

Fix for `SWTException` on `Table.remove(...)` with a focused row.
Cause: `gtk_list_store_remove(...)` for a focused row invokes `Table.cellDataProc(...)` with not-yet-updated `Table.items`.
Fix: remove `TableItem` from `Table.items` before `gtk_list_store_remove(...)`.

Fixes eclipse-platform#1606

This bug happens in Gtk3.
I haven't tried to reproduce this bug in GTK4.

Java stacktrace:
```java
org.eclipse.swt.SWTException: Widget is disposed
	at org.eclipse.swt.SWT.error(SWT.java:4922)
	at org.eclipse.swt.SWT.error(SWT.java:4837)
	at org.eclipse.swt.SWT.error(SWT.java:4808)
	at org.eclipse.swt.widgets.Widget.error(Widget.java:597)
	at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:512)
	at org.eclipse.swt.widgets.TableItem.setText(TableItem.java:1363)
	at org.eclipse.swt.tests.gtk.Test_Gtk3_Table_Remove_Focused_Row.lambda$3(Test_Gtk3_Table_Remove_Focused_Row.java:68)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:91)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5857)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1617)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1643)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1626)
	at org.eclipse.swt.widgets.Table.checkData(Table.java:289)
	at org.eclipse.swt.widgets.Table.cellDataProc(Table.java:227)
	at org.eclipse.swt.widgets.Display.cellDataProc(Display.java:995)
	at org.eclipse.swt.internal.gtk.GTK.gtk_list_store_remove(Native Method)
	at org.eclipse.swt.widgets.Table.remove(Table.java:2668)
	...
```

The main cause of the error is that:
 1. when a row with focus is deleted with `gtk_list_store_remove(...)`, then cell data function `Table.cellDataProc(...)` is called for a row after the removed one
 2. but inside `Table.cellDataProc(...)` `Table.items` isn't yet updated , therefore `Table.cellDataProc(...)` operates with `TableItem`, which is already disposed but not yet removed from `Table.items`

Inside `gtk_list_store_remove(...)` the row is removed from the `GtkTreeModel`, and only then `GtkTreeView` callbacks are invoked.
It means that when `Table.cellDataProc(...)` is invoked, the row has already been removed in Gtk3.

The fix: remove `TableItem` from `Table.items` before `gtk_list_store_remove(...)` instead of after.

Os:  Ubuntu 24.04.1 LTS
Gtk: 3.24.41
Swt: 4.967.8

=================================================

Why `gtk_list_store_remove(...)` invokes `Table.cellDataProc(...)` only for a row with focus and not for ordinary rows?

The reason is that in gtk3 when a row with focus is deleted, the next row receives focus, which among other things creates `GtkCellAccessible` (a "cell with focus" for assistive technology in gtk3).
Creation of `GtkCellAccessible` invokes cell data function `Table.cellDataProc(...)` - just like it happens when a standard cell in `GtkTreeView` gets rendered.

Here is the stacktrace in gtk3 code:
```c
apply_cell_attributes() at gtkcellarea.c:1257
g_hash_table_foreach() at ghash.c:2117
gtk_cell_area_real_apply_attributes() at gtkcellarea.c:1286
gtk_cell_area_box_apply_attributes() at gtkcellareabox.c:1310
_gtk_marshal_VOID__OBJECT_BOXED_BOOLEAN_BOOLEANv() at gtkmarshalers.c:5447
g_type_class_meta_marshalv() at gclosure.c:1062
_g_closure_invoke_va() at gclosure.c:897
signal_emit_valist_unlocked() at gsignal.c:3424
g_signal_emit_valist() at gsignal.c:3263
g_signal_emit() at gsignal.c:3583
gtk_cell_area_apply_attributes() at gtkcellarea.c:2373
gtk_tree_view_column_cell_set_cell_data() at gtktreeviewcolumn.c:2821
set_cell_data() at gtktreeviewaccessible.c:347
create_cell() at gtktreeviewaccessible.c:439
_gtk_tree_view_accessible_add_state() at gtktreeviewaccessible.c:2053
gtk_tree_view_real_set_cursor() at gtktreeview.c:13377
gtk_tree_view_row_deleted() at gtktreeview.c:9430
g_cclosure_marshal_VOID__BOXED() at gmarshal.c:1628
g_closure_invoke() at gclosure.c:834
signal_emit_unlocked_R() at gsignal.c:3888
signal_emit_valist_unlocked() at gsignal.c:3520
g_signal_emit_valist() at gsignal.c:3263
g_signal_emit() at gsignal.c:3583
gtk_tree_model_row_deleted() at gtktreemodel.c:1914
gtk_list_store_remove() at gtkliststore.c:1219
Java_org_eclipse_swt_internal_gtk_GTK_gtk_1list_1store_1remove()
```

The code that leads to execution of cell data function for a row with focus is in gtktreeview.c:
```
static void
gtk_tree_view_row_deleted (GtkTreeModel *model,
			   GtkTreePath  *path,
			   gpointer      data)
{
  ...
  /* If the cursor row got deleted, move the cursor to the next row */
  if (tree_view->priv->cursor_node &&
      (tree_view->priv->cursor_node == node ||
       (node->children && (tree_view->priv->cursor_tree == node->children ||
                           _gtk_rbtree_contains (node->children, tree_view->priv->cursor_tree)))))
    {
      ...
      cursor_changed = TRUE;
    }
  ...
  if (cursor_changed)
    {
      if (cursor_node)
        {
          ...
          gtk_tree_view_real_set_cursor (tree_view, cursor_path, CLEAR_AND_SELECT | CURSOR_INVALID);
          ...
        }
      ...
    }
  ...
}
```
This was referenced Nov 21, 2024
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@om-11-2024