[Lazarus] OI / App crash - components with published interfaces
Andreas Frieß
friess at gmx.at
Sun Feb 18 13:16:36 CET 2018
Now i have inserted code in the TIntfComp to remove the link to the
interface
--------------------
destructor TIntfComp.Destroy;
begin
FObjectHasInterface := nil; // <<-- Crahe here now
inherited Destroy;
end;
--------------------
And now i it crash explicitly at the line wher i try to 'unlink'. And
the Callstack from Lazarus give me some information. The setting to nil,
call fpc_intf_assign and call IUnknown(D)._Release. But this is
absolutly unwated (and unexpected) for me here.
How can i release the link without calling fpc_intf_assign. Or what is
my mistake of understanding ?
Andreas
-------------------------------
#0 fpc_intf_assign at :0
#1 DESTROY(0x3868750, 0x1) at intfcomp.pas:76
#2 CLASSES$_$TCOMPONENT_$__$$_DESTROYCOMPONENTS at :0
#3 CLASSES$_$TCOMPONENT_$__$$_DESTROY at :0
#4 ?? at :0
#5 DESTROY(0x3838d38, 0x0) at include\control.inc:5146
#6 DESTROY(0x3838d38, 0x0) at include\wincontrol.inc:6626
#7 DESTROY(0x3838d38, 0x0) at include\customcontrol.inc:40
#8 DESTROY(0x3838d38, 0x0) at include\scrollingwincontrol.inc:316
#9 DESTROY(0x3838d38, 0x1) at include\customform.inc:212
#10 SYSTEM$_$TOBJECT_$__$$_FREE at :0
#11 FREEUSEDOBJECTS(0x38648d8) at uoitest.pas:161
#12 BUFREECLICK(0x38648d8, 0x3865a58) at uoitest.pas:139
---------------------------
Am 17.02.2018 um 10:53 schrieb Andreas Frieß via Lazarus:
> I have an appcrash when i use components with interfaces in the
> published part. See also Bug 32919. I have now simpilied the problem
> and isolated from Lazarus itself.
>
> The component is on https://github.com/afriess/LazarusBug0032919 in
> OITestBasic, together with the testproject shown here.
>
> Somethigs goes wrong , if call free for the Form ( SIGSEGV ). A
> sencond issue is, i did not see the value of the property
> ObjectHasInterface in the OI. But i see the value if i click on the
> Combobox.
>
> My Question:
>
> Did i miss something in the definition of the Components ?
>
> ------------ definition components ---------------
>
> type
> // define the Interface
> ITestInterface = interface
> function OnlyDummy: integer;
> end;
>
> { TIntfComp }
> TIntfComp = class(TComponent)
> private
> FObjectHasInterface: ITestInterface;
> function GetObjectHasInterface: ITestInterface;
> procedure SetObjectHasInterface(AValue: ITestInterface);
> published
> property ObjectHasInterface: ITestInterface read
> GetObjectHasInterface write SetObjectHasInterface;
> end;
>
> { TCompHasIntf }
> TCompHasIntf = class(TComponent, ITestInterface)
> public
> function OnlyDummy: integer;
> end;
>
> --------- test programm ------------
>
> DUT := TObjectInspectorDlg.Create(nil);
> DUT.Caption:= 'My ObjectInspector';
>
> // create the PropertyEditorHook (the interface to the properties)
> ThePropertyEditorHook:=TPropertyEditorHook.Create(DUT);
> DUT.PropertyEditorHook:=ThePropertyEditorHook;
>
> // Create components
> ATestForm := TForm.Create(nil);
> ATestForm.Name:= 'Main';
>
> ATestIntf := TIntfComp.Create(ATestForm); // This componnets
> can hold a component with interface
> ATestIntf.Name := 'ATestIntf';
> ATestHasIntf := TCompHasIntf.Create(ATestForm); // This component
> has an Interface
> ATestHasIntf.Name:= 'ATestHasIntf';
> ATestIntf.ObjectHasInterface := ATestHasIntf;
> ATestIntf.GetParentComponent;
> ThePropertyEditorHook.LookupRoot:=ATestForm;
>
> PerList:=TPersistentSelectionList.Create;
> PerList.Add(ATestForm);
> DUT.Selection:=PerList;
> PerList.Free;
>
> DUT.Show;
>
> .......
>
> if DUT <> nil then begin
> ATestForm.Free; // <----- Appcrash
> FreeAndNil(DUT);
> end;
> ----------------------- End ------------------
>
>
> ------------------ Stack ------------------------
>
> #0 fpc_intf_decr_ref at :0
> #1 fpc_finalize at :0
> #2 ?? at :0
> #3 SYSTEM_$$_SETVARIANTMANAGER$TVARIANTMANAGER at :0
> #4 ?? at :0
> #5 DESTROY(0x3aa8868, 0x0) at include\control.inc:5146
> #6 DESTROY(0x3aa8868, 0x0) at include\wincontrol.inc:6626
> #7 DESTROY(0x3aa8868, 0x0) at include\customcontrol.inc:40
> #8 DESTROY(0x3aa8868, 0x0) at include\scrollingwincontrol.inc:316
> #9 DESTROY(0x3aa8868, 0x1) at include\customform.inc:212
> #10 SYSTEM$_$TOBJECT_$__$$_FREE at :0
> #11 FREEUSEDOBJECTS(0x3ad46f8) at uoitest.pas:161
> #12 BUFREECLICK(0x3ad46f8, 0x3ad5878) at uoitest.pas:139
> #13 CLICK(0x3ad5878) at include\control.inc:2929
> #14 CLICK(0x3ad5878) at include\buttoncontrol.inc:55
> #15 CLICK(0x3ad5878) at include\buttons.inc:169
> #16 WMDEFAULTCLICKED(0x3ad5878, {MSG = 66567, WPARAM = 0, LPARAM = 0,
> RESULT = 0, WPARAMLO = 0, WPARAMHI = 0, WPARAMFILLER = {}, LPARAMLO =
> 0, LPARAMHI = 0, LPARAMFILLER = {}, RESULTLO = 0, RESULTHI = 0,
> RESULTFILLER = {}}) at include\buttoncontrol.inc:21
> #17 SYSTEM$_$TOBJECT_$__$$_DISPATCH$formal at :0
> #18 ?? at :0
> #19 VMT_$STDCTRLS_$$_TBUTTONCONTROL at :0
> #20 VMT_$STDCTRLS_$$_TCUSTOMSTATICTEXT$indirect at :0
> #21 STDCTRLS$_$TBUTTONCONTROL_$__$$_ISCHECKEDSTORED$$BOOLEAN at :0
> #22 WNDPROC(0x3ad5878, {MSG = 66567, WPARAM = 0, LPARAM = 0, RESULT =
> 0, WPARAMLO = 0, WPARAMHI = 0, WPARAMFILLER = {}, LPARAMLO = 0,
> LPARAMHI = 0, LPARAMFILLER = {}, RESULTLO = 0, RESULTHI = 0,
> RESULTFILLER = {}}) at include\wincontrol.inc:5406
> #23 DELIVERMESSAGE(0x3ad5878, 0) at lclmessageglue.pas:112
> #24 DOWINDOWPROC(0x3b0d780) at win32\win32callback.inc:2534
> #25 WINDOWPROC(199064, 273, 22648, 1705918) at
> win32\win32callback.inc:2696
> #26 CUSTOMFORMWNDPROC(199064, 273, 22648, 1705918) at
> win32\win32wsforms.pp:386
> #27 USER32!AddClipboardFormatListener at :0
> #28 USER32!EndTask at :0
> #29 DEBUGSTART_$WIN32WSFORMS at :0
> #30 USER32!EndTask at :0
> #31 ?? at :0
> #32 USER32!EndTask at :0
> #33 DEBUGSTART_$WIN32WSFORMS at :0
> #34 USER32!SendMessageW at :0
> #35 CreateMappedBitmap at :0
> #36 ImageList_GetIconSize at :0
> #37 USER32!AddClipboardFormatListener at :0
> #38 USER32!EndTask at :0
> #39 ImageList_GetIconSize at :0
> #40 USER32!EndTask at :0
> #41 ?? at :0
> #42 USER32!EndTask at :0
> #43 ImageList_GetIconSize at :0
> #44 USER32!CallWindowProcW at :0
> #45 CALLDEFAULTWINDOWPROC(1705918, 514, 0, 1310774) at
> win32\win32callback.inc:97
> #46 DOWINDOWPROC(0x3b0d610) at win32\win32callback.inc:2442
> #47 WINDOWPROC(1705918, 514, 0, 1310774) at win32\win32callback.inc:2696
> #48 BUTTONWNDPROC(1705918, 514, 0, 1310774) at
> win32\win32wsstdctrls.pp:1791
> #49 USER32!AddClipboardFormatListener at :0
> #50 USER32!EndTask at :0
> #51
> WIN32WSSTDCTRLS$_$TWIN32WSBUTTONCONTROL_$__$$_GETPREFERREDSIZE$TWINCONTROL$LONGINT$LONGINT$BOOLEAN
> at :0
> #52 USER32!EndTask at :0
> #53 ?? at :0
> #54 USER32!DispatchMessageW at :0
> #55 USER32!DispatchMessageW at :0
> #56 APPPROCESSMESSAGES(0x3af7fd0) at win32\win32object.inc:407
> #57 HANDLEMESSAGE(0x3a98408) at include\application.inc:1276
> #58 RUNLOOP(0x3a98408) at include\application.inc:1413
> #59 APPRUN(0x3af7fd0, {Proc = {procedure (POINTER)} 0x177ff48, Self =
> 0x3a98408}) at include\interfacebase.inc:54
> #60 RUN(0x3a98408) at include\application.inc:1401
> #61 main at GuiOITest.lpr:19
> ------------------- End Stack ---------------------------
>
>
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