[fpc-pascal] "Variant array locked" error for now apparent reason

[Florian Klaempfl]

Graeme Geldenhuys schrieb:
> As the subject line says, I keep getting this error and I can't see why!
> I'm trying to get the last 4 unit test errors fixed running the tiOPF
> project under FPC 2.1.1. (latest SVN revision)
> 
> The tiOPF function tiVariantArrayToString() converts a Variant Array
> to a String. I placed some writeln() statements in the code to see how
> far it gets before the error occurs. As you can see from the backtrace
> output, that it finishes (exits) the function, and then the error
> occurs.  Also nowhere in the code do I lock the variant array, as I am
> not modifying it, just iterating through it's elements.
> 
> Hope someone can shed some light on this issue - I'm stuck!  :-(

I didn't look at it but please submit a bug report, so it won't be forgotten.

> 
> 
> 
> ------  Error Start  ------
>  <ListOfErrors>
>    <Error>
>      <Message>TTestTIUtils.tiVariantArrayToString: Variant array
> locked</Message>
>      <ExceptionClass>EVariantArrayLockedError</ExceptionClass>
>      <ExceptionMessage>Variant array locked</ExceptionMessage>
>     
> <SourceUnitName>/mnt/data/programming/3rdParty/tiOPF2/Source/Core/tiUtils.pas</SourceUnitName>
> 
>      <LineNumber>890</LineNumber>
>      <FailedMethodName>_INTTOSTR</FailedMethodName>
>    </Error>
>  </ListOfErrors>
> 
> ------  Error End  --------
> 
> 
> 
> ------------ The Code   ------------
> function  tiVariantArrayToString(AValue: Variant): string;
>  //---------
>  procedure appendVariantToStringList(pStringList: TStringList;
>      pVariant: Variant; var pIndent: integer);
>  var
>    i: integer;
>    iLow: integer;
>    iHigh: integer;
>  begin
>    if VarIsArray(pVariant) then
> //    if tiIsVariantOfType(pVariant, varArray) then
>    begin
>      iLow := varArrayLowBound(pVariant, 1);
>      iHigh := varArrayHighBound(pVariant, 1);
>      for i := iLow to iHigh do
>      begin
>        inc(pIndent);
> 
>        if i = iLow then
>          pStringList.add(tiSpace(pIndent*3) + '[');
> 
>        appendVariantToStringList(pStringList, pVariant[i], pIndent);
> 
>        if i = iHigh then
>          pStringList.add(tiSpace(pIndent*3) + ']');
> 
>        dec(pIndent);
>      end;
>    end
>    else
>    begin
>      pStringList.add(tiSpace(pIndent*3 + 1) + varToStr(pVariant));
>    end;
>  end;
> 
> var
>  lStringList : TStringList;
>  pIndent : integer;
>  dimcount: integer;
> begin
>  lStringList := TStringList.Create;
>  try
>    pIndent := -1;
> writeln('*** Start  ***');
>    appendVariantToStringList(lStringList, AValue, pIndent);
> writeln('*** Finish  ***');
>    result := lStringList.Text;
>  finally
>    lStringList.free;
>  end;
> writeln('*** Exit  ***');
> end;
> 
> -----------  Code End  --------------
> 
> ... and the backtrace ....
> 
> 
> -----------  Backtrace Start  ----------
> 
> (gdb) run
> Starting program: /UnitTests/GUI/fpcUnitTIOPFGui
> [Thread debugging using libthread_db enabled]
> [New Thread -1213237024 (LWP 12705)]
> InitKeyboardTables - Duplicate Keysymstring="=" for keycode=126 ignored.
>  Existing: vkey=57, flags=0x00 New: vkey=227, flags=0x00
> [New Thread -1215480912 (LWP 12711)]
> *** Start  ***
> *** Finish  ***
> *** Exit  ***
> 
> [Switching to Thread -1213237024 (LWP 12705)]
> 
> Breakpoint 1, 0x08060196 in fpc_raiseexception ()
> (gdb) bt
> #0  0x08060196 in fpc_raiseexception ()
> #1  0x0824c21c in VARIANTS_VARARRAYLOCKEDERROR () at tiUtils.pas:2784
> #2  0x0824c4c7 in VARIANTS_RAISEVAREXCEPTION$HRESULT () at tiUtils.pas:2784
> #3  0x0824c558 in VARIANTS_VARRESULTCHECK$HRESULT () at tiUtils.pas:2784
> #4  0x08247e69 in VARIANTS_SYSVARCLEARPROC$TVARDATA () at tiUtils.pas:2023
> #5  0x080605dd in SYSTEM_VARIANT_CLEAR$TVARDATA ()
> #6  0x08062326 in fpc_decref ()
> #7  0x0823e1c1 in TIVARIANTARRAYTOSTRING (AVALUE={VARIANT} 0xbfe6562c)
>    at tiUtils.pas:1309
> #8  0x082b6bb5 in TTESTTIUTILS__TIVARIANTARRAYTOSTRING (this=0xb78eb240)
>    at tiUtils_TST.pas:1709
> #9  0x082007e7 in FPCUNIT_TTESTCASE_$__RUNTEST ()
> #10 0x0820071e in FPCUNIT_TTESTCASE_$__RUNBARE ()
> #11 0x082017aa in FPCUNIT_PROTECTTEST$TTEST$TTESTRESULT ()
> #12 0x082018a1 in FPCUNIT_TTESTRESULT_$__RUNPROTECTED$TTEST$TPROTECT ()
> #13 0x082017e0 in FPCUNIT_TTESTRESULT_$__RUN$TTESTCASE ()
> #14 0x082006cb in FPCUNIT_TTESTCASE_$__RUN$TTESTRESULT ()
> #15 0x082011c1 in FPCUNIT_TTESTSUITE_$__RUNTEST$TTEST$TTESTRESULT ()
> #16 0x083cf820 in _$FPCUNIT$_Ld39 ()
> #17 0x08201176 in FPCUNIT_TTESTSUITE_$__RUN$TTESTRESULT ()
> #18 0x00000070 in ?? ()
> #19 0xb7f4f760 in ?? ()
> #20 0xb70a1980 in ?? ()
> #21 0x00140022 in ?? ()
> #22 0xb7a93680 in ?? ()
> <...snip...>
> ----------- Backtrace End ---------------
> 
>