Passing pseudo-widget handle as TABLE-HANDLE or DATASET-HANDLE is not handled correctly

Passing one of the built-in system-handles as TABLE-HANDLE or DATASET-HANDLE fails to raise the expected error conditions. Instead, the ABL code executes in an unpredictable way or the session crashes.

Oct 9, 2018
Knowledge

Title

URL Name

000034237

Article Number

000169512

Environment

Product: OpenEdge Version: 10.2B, 11.x OS: All Supported Platforms

Question/Problem Description

If the handle to a PSEUDO-WIDGET (for example: the SESSION handle or other system handles) is mistakenly passed to a procedure as a TABLE-HANDLE or DATASET-HANDLE parameter, the AVM does not recognize that the object is the wrong type.

This causes the session to crash, or the ABL code to be executed in an unpredictable fashion.

It does not matter if the receiving end defines the dataset/temp-table as a static object or a dynamic handle; the critical condition is that the sending routine uses a DATASET-HANDLE myHandle or TABLE-HANDLE myHandle, where myHandle is a HANDLE type that is set to a PSEUDO-WIDGET.

Steps to Reproduce

The following code demonstrates one specific occurence of the defect, and will crash the AVM:

Clarifying Information

/* definitions */
DEFINE TEMP-TABLE ttTest NO-UNDO
    FIELD cTest AS CHARACTER.
DEFINE DATASET dsTest FOR ttTest.

DEFINE VARIABLE hWrongobject AS HANDLE      NO-UNDO.

/* internal procedures */
PROCEDURE staticds:
   DEFINE INPUT PARAMETER DATASET FOR dsTest.
END.

/* Attempt to pass the session handle as an INPUT DATASET-HANDLE */
hWrongobject = SESSION.

RUN staticds (INPUT DATASET-HANDLE hWrongobject).

The expected error messages are:
TEMP-TABLE handle parameter requires valid and prepared handle. (9068) for a temp-table parameter or
Invalid DATASET-HANDLE parameter given. (12314) for a dataset parameter

These errors do occur as expected if the handle points to an ABL object of another incorrect type, such as when trying to pass the handle to a temp-table as a DATASET-HANDLE.

Error Message

Defect Number

Defect# PSC00247116/OE00224164

Enhancement Number

Cause

The type-checking fails to block pseudo-widgets from being passed.

The different symptoms that occur as a result are because the AVM ends up trying to handle the wrong type of object.

Resolution

Until the fix is available, use the workaround below.

Workaround

If needed, check the type of the handle before passing it as a parameter, for example:

IF hObject:TYPE = "DATASET":U
THEN RUN myProc (INPUT DATASET-HANDLE hObject).
ELSE MESSAGE "handle points to object of wrong type" VIEW-AS ALERT-BOX.

Notes

Keyword Phrase

Last Modified Date

10/9/2018 3:47 PM

Passing pseudo-widget handle as TABLE-HANDLE or DATASET-HANDLE is not handled correctly

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