Scrollbox divide by zero error

[Hansvb]

Hi,
On a scrollbox I put a few panels and splitters. Because updating the scrollbox is very slow, I was looking what happened when i use ScrollBox1.DisableAutoSizing. Then I get a divide by zero error and the LazTracer unit opens. It stops in the procedure RaiseGDBException of the unit unit LazTracer.

This is the function:

Code: Pascal  [Select][+][-]

1. procedure RaiseGDBException(const Msg: string);
2. begin
3.   DebugLn(lrsERRORInCode, Msg);
4.   // creates an exception, that gdb catches:
5.   DebugLn(lrsCreatingGdbCatchableError);
6.   DumpStack;
7.   {$ifndef HASAMIGA} // On Amiga Division by 0 is not catchable, just crash
8.   if (length(Msg) div (length(Msg) div 10000))=0 then ;  
9.   {$endif}
10. end;

the error happens in the line:

Code: Pascal  [Select][+][-]

1. if (length(Msg) div (length(Msg) div 10000))=0 then ;

The cause is that Msg is empty.
It should have been something like this:

Code: Pascal  [Select][+][-]

1.   {$ifndef HASAMIGA} // On Amiga Division by 0 is not catchable, just crash
2.   if  Msg = '' then Exit;
3.   if (length(Msg) div (length(Msg) div 10000))=0 then ;  
4.   {$endif}

If i look in the callstack window and if I see it correctly then the function is called from

Code: Pascal  [Select][+][-]

1. procedure TWinControl.DoAllAutoSize;

from wincontrol.inc. The call for it is:

Code: Pascal  [Select][+][-]

1. if cfAutoSizeNeeded in FControlFlags then RaiseGDBException('');

this one calls RaiseGDBException with an empty Msg?


Reproducible with attached project. If you move splitter 2 you will get the divide by zero message. It feels like  a bug.

Used: Windows 11,  Lazarus 4.6.