fix: crash when cancelling session manager while a session rename is active

Two independent crashes on macOS were hidden behind this repro, since
cancelling the session manager at startup also exits the application:

1. The session manager starts an inline rename right after creating a
   new session. When the form was closed via Cancel, the edit link's
   queued async EndEditNode call fired after the tree was already
   destroyed, and its focus restoration ran into
   "[TCustomForm.SetFocus] connform:Tconnform Can not focus".
   Remove pending async edit calls when an editor link is destroyed,
   cancel a pending inline rename before the form closes, and let
   TrySetFocus test CanSetFocus, which - unlike CanFocus - also checks
   the parent form itself, so it does not raise in the first place.

2. On shutdown, TSynBaseCompletionForm.Destroy (SynEdit) first frees its
   SizeDrag panel and then destroys the window handle. The Cocoa
   widgetset queries Focused during DestroyHandle, and SynEdit's Focused
   override dereferences the freed SizeDrag, raising
   "EObjectCheck: Object reference is Nil" on every macOS shutdown.
   Work around it by destroying the completion form's handle in
   FormDestroy while the form is still intact.

Fixes issue 2433

Author: twinn1013

source/apphelpers.pas

@@ -3528,7 +3528,11 @@ procedure TClipboardHelper.SetTryAsText(AValue: String);
 procedure TWinControlHelper.TrySetFocus;
 begin
   try
-    if Enabled and CanFocus then
+    // CanSetFocus - unlike CanFocus - also tests the parent form itself, so
+    // this avoids the "[TCustomForm.SetFocus] ... Can not focus" exception
+    // which SetFocus raises on a hidden or disabled form, e.g. while a modal
+    // form is closing. See issue 2433.
+    if CanSetFocus then
       SetFocus
     else
       MainForm.LogSQL(Self.Name + ': either disabled or cannot focus', lcDebug);

source/connections.pas

@@ -384,6 +384,12 @@ procedure Tconnform.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
 begin
   // Modifications? Ask if they should be saved.
   FinalizeModifications(CanClose);
+  // End a pending inline rename while the form is still visible and active.
+  // Otherwise the edit link tries to restore the focus during form teardown,
+  // which raises "[TCustomForm.SetFocus] ... Can not focus" on macOS.
+  // See issue #2433.
+  if CanClose and ListSessions.IsEditing then
+    ListSessions.CancelEditNode;
 end;
 
 

source/grideditlinks.pas

@@ -279,6 +279,11 @@ destructor TBaseGridEditorLink.Destroy;
   NewNode: PVirtualNode;
   DoPrev: Boolean;
 begin
+  // Drop end/cancel calls which are still queued via DoEndEdit/DoCancelEdit.
+  // They would fire after this link - and possibly the tree or its form - is
+  // already destroyed, e.g. when the session manager is cancelled while a
+  // session rename is active. See issue #2433.
+  Application.RemoveAsyncCalls(Self);
   ActiveGridEditor := nil;
   if Assigned(FMainControl) then begin
     FMainControl.WindowProc := FOldWindowProc;

source/main.pas

@@ -1776,11 +1776,29 @@ procedure TMainForm.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
     CanClose := not (ActiveObjectEditor.DeInit in [mrAbort, mrCancel]);
 end;
 
+{$IFDEF DARWIN}
+type
+  // Grants access to the protected DestroyHandle, see workaround in FormDestroy
+  TWinControlAccess = class(TWinControl);
+{$ENDIF}
+
 procedure TMainForm.FormDestroy(Sender: TObject);
 begin
   // Discard a possibly queued AsyncRepaintGrid call
   Application.RemoveAsyncCalls(Self);
 
+  {$IFDEF DARWIN}
+  // Work around a SynEdit bug which crashes the app on every shutdown on Cocoa:
+  // TSynBaseCompletionForm.Destroy first frees its SizeDrag panel and then
+  // destroys the window handle. The Cocoa widgetset queries Focused while
+  // destroying the handle, and the Focused override dereferences the already
+  // freed SizeDrag ("EObjectCheck: Object reference is Nil"). Destroying the
+  // handle here, while the form is still intact, makes the destructor skip
+  // that path. See issue 2433.
+  if SynCompletionProposal.TheForm.HandleAllocated then
+    TWinControlAccess(SynCompletionProposal.TheForm).DestroyHandle;
+  {$ENDIF}
+
   // Destroy dialogs
   FreeAndNil(FSearchReplaceDialog);