xbrowse : sporadic error

[Demont Brecht]

Hello,

In a intensive used aplication i got sporadic (4 errors in 2 years) , at line 396 :

METHOD ColAtPos( nPos ) INLINE ::aCols[ ::aDisplay[ MinMax( If( nPos == nil, 1, nPos ), 1, Len( ::aDisplay ) ) ] ]

With :

#xtranslate MinMax( <xValue>, <nMin>, <nMax> ) => ;
Min( Max( <xValue>, <nMin> ), <nMax> )

The error indicates

Error description: Error BASE/1132 Bound error: array access
Args:
[ 1] = A { ... }
[ 2] = N 0

ColAtPos seems to be called with parameter 1. When Minmax returns 0 , it can only be declared as LEN(::aDisplay) == 0

I can simulate this error with hiding all the columns from the browse . It gives the same error , but the calllist is much longer.

I have no idea how ::aDisplay can become empty , for this browe ocol:hide() is not used at all

I note also that the error occurs always on the same computer ( network from +/- 10 computers) , so could it be a hardware problem ?

Frank

[ukservice]

I do get it very often:

It is not a hardware problem.

It happens randomly when painting xBrowse.

Code: Select all | Expand

  Error description: Error BASE/1132  Bound error: array access

   Args:
     [   1] = A   { ... }
     [   2] = N   0

Stack Calls
===========
   Called from: source\xbrowse.prg => (b)TXBROWSE(517)
   Called from: source\xbrowse.prg => TXBROWSE:COLATPOS(0)
   Called from: source\xbrowse.prg => (b)TXBROWSE(519)
   Called from: source\xbrowse.prg => TXBROWSE:SELECTEDCOL(0)
   Called from: source\xbrowse.prg => TXBROWSE:PAINT(1250)
   Called from: source\xbrowse.prg => TXBROWSE:DISPLAY(1228)
   Called from: .\source\classes\CONTROL.PRG => TCONTROL:HANDLEEVENT(1686)
   Called from: source\xbrowse.prg => TXBROWSE:HANDLEEVENT(11511)
   Called from: .\source\classes\WINDOW.PRG => _FWH(3443)
   Called from:  => DIALOGBOX(0)
   Called from: .\source\classes\DIALOG.PRG => TDIALOG:ACTIVATE(277)
 

[Antonio Linares]

Demont,

Please try it this way:

METHOD ColAtPos( nPos ) INLINE ::aCols[ ::aDisplay[ MinMax( If( nPos == nil, 1, nPos ), 1, Max( Len( ::aDisplay ), 1 ) ) ] ]

[Demont Brecht]

Antonio,

/*
METHOD ColAtPos( nPos ) INLINE ::aCols[ ::aDisplay[ MinMax( If( nPos == nil, 1, nPos ), 1, Max( Len( ::aDisplay ), 1 ) ) ] ]
*/

I don't believe it will solve the problem , the real problem is that for some reason ::aDisplay is empty. With this corection we have ::aDisplay[1] , it should also give a error.

The translate :

#xtranslate MinMax( <xValue>, <nMin>, <nMax> ) => Min( Max( <xValue>, <nMin> ), <nMax> )

doesn't work when for some reason nMax < nMin , the translate gives then nMax ( the lowest value from nmin,nmax)

#xtranslate MinMax( <xValue>, <nMin>, <nMax> ) => Min( Max( <xValue>, MIN(<nMin>,<nMax>) ), MAX(<nMin>,<nMax>) )

Should work !

[nageswaragunupudi]

I don't believe it will solve the problem , the real problem is that for some reason ::aDisplay is empty.

Yes.
This is the real reason.
One case was resolved recently. When HScroll bar is moved in a single column browse, this was happening. This was fixed.

We need to see under what other situations ::aDisplay is becoming empty. Any feedback on this is welcome.

[Demont Brecht]

With version 8.10 i got nearly the same callist.

I do not understand this callist . Simulating this error , we got the error when the dialog is build , but the list is longer , the first 7 items :
original error list :
Called from: \MCLS\HENWIN8.10\fwh8.10\changed\ChangedSource\xbrowse.prg => (b)TXBROWSE:TXBROWSE(396)
Called from: => TXBROWSE:COLATPOS(0)
Called from: \MCLS\HENWIN8.10\fwh8.10\changed\ChangedSource\xbrowse.prg => TXBROWSE:PAINT(996)
Called from: \MCLS\HENWIN8.10\fwh8.10\changed\ChangedSource\xbrowse.prg => TXBROWSE:DISPLAY(922)
Called from: .\source\classes\CONTROL.PRG => TXBROWSE:HANDLEEVENT(0)
Called from: \MCLS\HENWIN8.10\fwh8.10\changed\ChangedSource\window.prg => _FWH(3308)
Called from: => WINRUN(0)
Sumulating :
Called from: \MCLS\HENWIN8.10\fwh8.10\changed\ChangedSource\xbrowse.prg => (b)TXBROWSE:TXBROWSE(396)
Called from: => TXBROWSE:COLATPOS(0)
Called from: \MCLS\HENWIN8.10\fwh8.10\changed\ChangedSource\xbrowse.prg => TXBROWSE:PAINT(996)
Called from: \MCLS\HENWIN8.10\fwh8.10\changed\ChangedSource\xbrowse.prg => TXBROWSE:DISPLAY(922)
Called from: .\source\classes\CONTROL.PRG => TXBROWSE:HANDLEEVENT(0)
Called from: \MCLS\HENWIN8.10\fwh8.10\changed\ChangedSource\window.prg => _FWH(3308)
Called from: => CREATEDLG(0)
So the error doesn't occur when the dialog is build , maybe when the dialog becomes focus. In ACTIVATE DIALOG i have NOMODAL

I do get it very often:

It is not a hardware problem.

It happens randomly when painting xBrowse.

Code: Select all | Expand

  Error description: Error BASE/1132  Bound error: array access

   Args:
     [   1] = A   { ... }
     [   2] = N   0

Stack Calls
===========
   Called from: source\xbrowse.prg => (b)TXBROWSE(517)
   Called from: source\xbrowse.prg => TXBROWSE:COLATPOS(0)
   Called from: source\xbrowse.prg => (b)TXBROWSE(519)
   Called from: source\xbrowse.prg => TXBROWSE:SELECTEDCOL(0)
   Called from: source\xbrowse.prg => TXBROWSE:PAINT(1250)
   Called from: source\xbrowse.prg => TXBROWSE:DISPLAY(1228)
   Called from: .\source\classes\CONTROL.PRG => TCONTROL:HANDLEEVENT(1686)
   Called from: source\xbrowse.prg => TXBROWSE:HANDLEEVENT(11511)
   Called from: .\source\classes\WINDOW.PRG => _FWH(3443)
   Called from:  => DIALOGBOX(0)
   Called from: .\source\classes\DIALOG.PRG => TDIALOG:ACTIVATE(277)
 

[Demont Brecht]

See also mine previous post.

The program uses obrw:bGotfocus.

oBrw:bGotFocus := { ||TestHid(oBrw,oCol) , .......}

PROC TestHid(oBrw,oCol)
STATIC n := 0
IF n > 0 // prevent error when the dialog is created
FOR EACH oCol IN oBrw:aCols
oCol:Hide()
NEXT
END
n++
RETURN

I got exact the same error list as mine user

Frank

I don't believe it will solve the problem , the real problem is that for some reason ::aDisplay is empty.

Yes.
This is the real reason.
One case was resolved recently. When HScroll bar is moved in a single column browse, this was happening. This was fixed.

We need to see under what other situations ::aDisplay is becoming empty. Any feedback on this is welcome.

[nageswaragunupudi]

#1. You should never hide all columns. Atleast one column should be visible.

#2. When there is only one column in the browse, using horizontal scroll bar was resulting in this error. This is fixed in the latest version. For previous versions, the work around was not to have HScroll bar when there is only one column in the browse.

[Demont Brecht]

Nages ,

I try to simulate the same error list from mine user. I have no intention to hide all the columns in a browse

Frank

#1. You should never hide all columns. Atleast one column should be visible.

#2. When there is only one column in the browse, using horizontal scroll bar was resulting in this error. This is fixed in the latest version. For previous versions, the work around was not to have HScroll bar when there is only one column in the browse.

[nageswaragunupudi]

Nages ,

I try to simulate the same error list from mine user. I have no intention to hide all the columns in a browse

Frank

I understand and appreciate.

This also means that we need to take care of a situation where the user by himself hides all columns. We need to protect this either in the application program or in xbrowse. Later option is better. We shall see how we can do this within xbrowse.prg. But for existing applications, the applications need to take care of this possibility. Thanks for your feedback.

We would also be interested in knowing if this error is encountered in any situations other than the two I mentioned above.

We are always grateful for your feedback, because that helps us to improve the library.

[Demont Brecht]

Rao ,

I tested to hide all columns (8.10) , but xbrowse doesn't allow to hide the last column.

Frank

[nageswaragunupudi]

That means the user can not hide all columns.
If at all all columns are hidden that is done by the programmer. Ofcourse we expect the programmer not to do it. So this is not an issue.

[ukservice]

Mr. Nao,

In my case, I don´t hide any columns.

The error appears just ramdonly.

[ukservice]

Hello again,

I am getting this error more often. Sometimes when the dbf is empty.

Is there any advance?.

Thank you.

[Antonio Linares]

aDisplay is created from METHOD GetDisplayCols() CLASS TXBrowse, so I guess thats where we could place some traces:

1. If you are not using any frozen coluns, then this loop should not be executed:

Code: Select all | Expand

   do while nFreeze > 0 .and. nCol <= nLen
      oCol := ::aCols[ nCol ]
      if ! oCol:lHide
         AAdd( aDisplay, nCol )
         oCol:nPos := Len( aDisplay )
         nFreeze--
      endif
      nCol++
   enddo

2. In the above case, aDisplay will be generated here:

Code: Select all | Expand

   do while nCol <= nLen
      oCol := ::aCols[ nCol ]
      if ! oCol:lHide
         AAdd( aDisplay, nCol )
         oCol:nPos := Len( aDisplay )
      endif
      nCol++
   enddo

So we could place a trace just after it:

Code: Select all | Expand

   if Len( aDisplay ) == 0
      MsgInfo( "aDisplay is zero! and nCol is: " + AllTrim( Str( nCol ) ) + " nLen is: " + AllTrim( Str( nLen ) ) )
   endif

   ::aDisplay := aDisplay
 

nLen is the total amount of columns.

For those of you that are able to reproduce the error, we kindly ask you to use the above trace and tell us what you get, thanks!