The Delphi Bug List

Entry No.
252

Debugger
If you have a conditional breakpoint in your source and you are stepping through the program (with F8), when you step to the line where the conditional breakpoint is, it acts as a 'debugging boobytrap': the program doesn't stop on that line and also not on the next line; it just starts running again.

1.02	2.01	3.0	3.01	3.02	4.0	4.01	4.02	4.03	5.0	5.01	6.0	6.01	6.02	Kylix 1.0
Unknown	Unknown	Unknown	Unknown	Unknown	Exists	Exists	Exists	Exists	Exists	Exists	Fixed	Fixed	Fixed	Exists

Description

Checked by Reinier Sterkenburg

Comment from checker, 10 June 2001
Apparently the bug does not 'happen' all the time (see also Anders Melander's remark below).
At the moment, I cannot reproduce the bug under Delphi either on my own PC. But I have seen this happening at least with Delphi 4 and Delphi 5, and there was also an independent confirmation by somebody else.

Under Kylix, the behaviour is not exactly the same as under Delphi but still something odd happens (goes wrong).
To reproduce:

Create a new application

Place a button on the form and attach the following code to the event handler

procedure TForm1.Button1Click(Sender: TObject);
begin
  Caption := Button1.Caption;
  Button1.Caption := 'tralala';
  Button1.Left := Button1.Left + 10;
end;

Set an unconditional breakpoint on the first line (Caption := Button1.Caption;)
Set a conditional breakpoint on the second line, with the condition Caption='Button1'
Run the program
press Button1: the program stops at the first line, with the unconditional breakpoint
Press F8 (Step): the following error appears: Internal Eror XEV-1444

User-contributed comments

Anders Melander
06 Apr 2001 11:00 AM GMT

I can't reproduce this problem with Delphi 5.01. Here's what I did:

Suppose I have the following code:

begin
a := 1; // #1) Set unconditional break point here
b := 2; // #2) Set conditional break point here. Condition: a=b
c := 3; // #3) This line should be skipped
end;

When stepping through the above the debuger behaves as expected; It breaks on line #1 and steps on to line #2 and then line #3.

Btw, this entry (and others) is listed in the "what's new" as "still exists in 5.01" but according to the version grid it hasn't been reported for versions earlier than 5.01.

Latest update of this entry: 2002-04-03

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