const char *name2,		/* Second part of variable name. */
    int flags)			/* Information about what happened. */
{
    register TkButton *butPtr = clientData;
    const char *value;
    Tcl_Obj *valuePtr;














    /*
     * If the variable is being unset, then just re-establish the trace unless
     * the whole interpreter is going away.
     */

    if (flags & TCL_TRACE_UNSETS) {
	butPtr->flags &= ~(SELECTED | TRISTATED);
	if (!Tcl_InterpDeleted(interp)) {
	    ClientData probe = NULL;

	    do {
		probe = Tcl_VarTraceInfo(interp,
			Tcl_GetString(butPtr->selVarNamePtr),
			TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
			ButtonVarProc, probe);
		if (probe == (ClientData)butPtr) {
		    break;
		}
	    } while (probe);
	    if (probe) {
		/* 
		 * We were able to fetch the unset trace for our
		 * selVarNamePtr, which means it is not unset and not
		 * the cause of this unset trace. Instead some outdated
		 * former variable must be, and we should ignore it.
		 */
		goto redisplay;
	    }
	    Tcl_TraceVar2(interp, Tcl_GetString(butPtr->selVarNamePtr),
		    NULL, TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
		    ButtonVarProc, clientData);
	}
	goto redisplay;
    }

 */

	/* ARGSUSED */
static char *
ButtonTextVarProc(
    ClientData clientData,	/* Information about button. */
    Tcl_Interp *interp,		/* Interpreter containing variable. */
    const char *name1,		/* Not used. */
    const char *name2,		/* Not used. */
    int flags)			/* Information about what happened. */
{
    TkButton *butPtr = clientData;
    Tcl_Obj *valuePtr;

    if (butPtr->flags & BUTTON_DELETED) {
	return NULL;
    }














    /*
     * If the variable is unset, then immediately recreate it unless the whole
     * interpreter is going away.
     */

    if (flags & TCL_TRACE_UNSETS) {
	if (!Tcl_InterpDeleted(interp) && butPtr->textVarNamePtr != NULL) {

	    /*
	     * An unset trace on some variable brought us here, but is it
	     * the variable we have stored in butPtr->textVarNamePtr ? 
	     */

	    ClientData probe = NULL;

	    do {
		probe = Tcl_VarTraceInfo(interp,
			Tcl_GetString(butPtr->textVarNamePtr),
			TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
			ButtonTextVarProc, probe);
		if (probe == (ClientData)butPtr) {
		    break;
		}
	    } while (probe);
	    if (probe) {
		/* 
		 * We were able to fetch the unset trace for our
		 * textVarNamePtr, which means it is not unset and not
		 * the cause of this unset trace. Instead some outdated
		 * former textvariable must be, and we should ignore it.
		 */
		return NULL;
	    }

	    Tcl_ObjSetVar2(interp, butPtr->textVarNamePtr, NULL,
		    butPtr->textPtr, TCL_GLOBAL_ONLY);
	    Tcl_TraceVar2(interp, Tcl_GetString(butPtr->textVarNamePtr),
		    NULL, TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
		    ButtonTextVarProc, clientData);
	}
	return NULL;

 */

	/* ARGSUSED */
static char *
EntryTextVarProc(
    ClientData clientData,	/* Information about button. */
    Tcl_Interp *interp,		/* Interpreter containing variable. */
    const char *name1,		/* Not used. */
    const char *name2,		/* Not used. */
    int flags)			/* Information about what happened. */
{
    Entry *entryPtr = clientData;
    const char *value;

    if (entryPtr->flags & ENTRY_DELETED) {
	/*
	 * Just abort early if we entered here while being deleted.
	 */
	return NULL;
    }














    /*
     * If the variable is unset, then immediately recreate it unless the whole
     * interpreter is going away.
     */

    if (flags & TCL_TRACE_UNSETS) {
        if (!Tcl_InterpDeleted(interp) && entryPtr->textVarName) {
            ClientData probe = NULL;

            do {
                probe = Tcl_VarTraceInfo(interp,
                        entryPtr->textVarName,
                        TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
                        EntryTextVarProc, probe);
                if (probe == (ClientData)entryPtr) {
                    break;
                }
            } while (probe);
            if (probe) {
                /*
                 * We were able to fetch the unset trace for our
                 * textVarName, which means it is not unset and not
                 * the cause of this unset trace. Instead some outdated
                 * former variable must be, and we should ignore it.
                 */
                return NULL;
            }
	    Tcl_SetVar2(interp, entryPtr->textVarName, NULL,
		    entryPtr->string, TCL_GLOBAL_ONLY);
	    Tcl_TraceVar2(interp, entryPtr->textVarName, NULL,
		    TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
		    EntryTextVarProc, clientData);
	    entryPtr->flags |= ENTRY_VAR_TRACED;
	}

 *----------------------------------------------------------------------
 */

static char *
ListboxListVarProc(
    ClientData clientData,	/* Information about button. */
    Tcl_Interp *interp,		/* Interpreter containing variable. */
    const char *name1,		/* Not used. */
    const char *name2,		/* Not used. */
    int flags)			/* Information about what happened. */
{
    Listbox *listPtr = clientData;
    Tcl_Obj *oldListObj, *varListObj;
    int oldLength, i;
    Tcl_HashEntry *entry;














    /*
     * Bwah hahahaha! Puny mortal, you can't unset a -listvar'd variable!
     */

    if (flags & TCL_TRACE_UNSETS) {

        if (!Tcl_InterpDeleted(interp) && listPtr->listVarName) {
            ClientData probe = NULL;

            do {
                probe = Tcl_VarTraceInfo(interp,
                        listPtr->listVarName,
                        TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
                        ListboxListVarProc, probe);
                if (probe == (ClientData)listPtr) {
                    break;
                }
            } while (probe);
            if (probe) {
                /*
                 * We were able to fetch the unset trace for our
                 * listVarName, which means it is not unset and not
                 * the cause of this unset trace. Instead some outdated
                 * former variable must be, and we should ignore it.
                 */
                return NULL;
            }
	    Tcl_SetVar2Ex(interp, listPtr->listVarName, NULL,
		    listPtr->listObj, TCL_GLOBAL_ONLY);
	    Tcl_TraceVar2(interp, listPtr->listVarName,
		    NULL, TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
		    ListboxListVarProc, clientData);
	    return NULL;
	}

    int flags)			/* Describes what just happened. */
{
    TkMenuEntry *mePtr = clientData;
    TkMenu *menuPtr;
    const char *value;
    const char *name, *onValue;

    if (Tcl_InterpDeleted(interp) || (mePtr->namePtr == NULL)) {
	/*
	 * Do nothing if the interpreter is going away or we have
	 * no variable name.
	 */

    	return NULL;
    }

    menuPtr = mePtr->menuPtr;

    if (menuPtr->menuFlags & MENU_DELETION_PENDING) {
    	return NULL;











    }

    name = Tcl_GetString(mePtr->namePtr);

    /*
     * If the variable is being unset, then re-establish the trace.
     */

    if (flags & TCL_TRACE_UNSETS) {
        ClientData probe = NULL;
	mePtr->entryFlags &= ~ENTRY_SELECTED;

        do {
                probe = Tcl_VarTraceInfo(interp, name,
                        TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
                        MenuVarProc, probe);
                if (probe == (ClientData)mePtr) {
                    break;
                }
        } while (probe);
        if (probe) {
                /* 
                 * We were able to fetch the unset trace for our
                 * namePtr, which means it is not unset and not
                 * the cause of this unset trace. Instead some outdated
                 * former variable must be, and we should ignore it.
                 */
		return NULL;
        }
	Tcl_TraceVar2(interp, name, NULL,
		TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
		MenuVarProc, clientData);
	TkpConfigureMenuEntry(mePtr);
	TkEventuallyRedrawMenu(menuPtr, NULL);
	return NULL;
    }

    /*
     * Use the value of the variable to update the selected status of the menu

 *	Arrange for an entry of a menu, or the whole menu, to be redisplayed
 *	at some point in the future.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	A when-idle handler is scheduled to do the redisplay, if there isn't
 *	one already scheduled.
 *
 *----------------------------------------------------------------------
 */

void
TkEventuallyRedrawMenu(

    const char *name2,		/* Second part of variable name. */
    int flags)			/* Information about what happened. */
{
    register TkMenuButton *mbPtr = clientData;
    const char *value;
    unsigned len;














    /*
     * If the variable is unset, then immediately recreate it unless the whole
     * interpreter is going away.
     */

    if (flags & TCL_TRACE_UNSETS) {
        if (!Tcl_InterpDeleted(interp) && mbPtr->textVarName) {
            ClientData probe = NULL;

            do {
                probe = Tcl_VarTraceInfo(interp,
                        mbPtr->textVarName,
                        TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
                        MenuButtonTextVarProc, probe);
                if (probe == (ClientData)mbPtr) {
                    break;
                }
            } while (probe);
            if (probe) {
                /*
                 * We were able to fetch the unset trace for our
                 * textVarName, which means it is not unset and not
                 * the cause of this unset trace. Instead some outdated
                 * former variable must be, and we should ignore it.
                 */
                return NULL;
            }
	    Tcl_SetVar2(interp, mbPtr->textVarName, NULL, mbPtr->text,
		    TCL_GLOBAL_ONLY);
	    Tcl_TraceVar2(interp, mbPtr->textVarName, NULL,
		    TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
		    MenuButtonTextVarProc, clientData);
	}
	return NULL;

    const char *name1,		/* Name of variable. */
    const char *name2,		/* Second part of variable name. */
    int flags)			/* Information about what happened. */
{
    register Message *msgPtr = clientData;
    const char *value;














    /*
     * If the variable is unset, then immediately recreate it unless the whole
     * interpreter is going away.
     */

    if (flags & TCL_TRACE_UNSETS) {
        if (!Tcl_InterpDeleted(interp) && msgPtr->textVarName) {
            ClientData probe = NULL;

            do {
                probe = Tcl_VarTraceInfo(interp,
                        msgPtr->textVarName,
                        TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
                        MessageTextVarProc, probe);
                if (probe == (ClientData)msgPtr) {
                    break;
                }
            } while (probe);
            if (probe) {
                /*
                 * We were able to fetch the unset trace for our
                 * textVarName, which means it is not unset and not
                 * the cause of this unset trace. Instead some outdated
                 * former variable must be, and we should ignore it.
                 */
                return NULL;
            }
	    Tcl_SetVar2(interp, msgPtr->textVarName, NULL, msgPtr->string,
		    TCL_GLOBAL_ONLY);
	    Tcl_TraceVar2(interp, msgPtr->textVarName, NULL,
		    TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
		    MessageTextVarProc, clientData);
	}
	return NULL;

{
    register TkScale *scalePtr = clientData;
    const char *resultStr;
    double value;
    Tcl_Obj *valuePtr;
    int result;














    /*
     * If the variable is unset, then immediately recreate it unless the whole
     * interpreter is going away.
     */

    if (flags & TCL_TRACE_UNSETS) {
        if (!Tcl_InterpDeleted(interp) && scalePtr->varNamePtr) {
            ClientData probe = NULL;

            do {
                probe = Tcl_VarTraceInfo(interp,
                        Tcl_GetString(scalePtr->varNamePtr),
                        TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
                        ScaleVarProc, probe);
                if (probe == (ClientData)scalePtr) {
                    break;
                }
            } while (probe);
            if (probe) {
                /* 
                 * We were able to fetch the unset trace for our
                 * varNamePtr, which means it is not unset and not
                 * the cause of this unset trace. Instead some outdated
                 * former variable must be, and we should ignore it.
                 */
                return NULL;
            }
	    Tcl_TraceVar2(interp, Tcl_GetString(scalePtr->varNamePtr),
		    NULL, TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
		    ScaleVarProc, clientData);
	    scalePtr->flags |= NEVER_SET;
	    TkScaleSetValue(scalePtr, scalePtr->value, 1, 0);
	}
	return NULL;

/*
 * Tcl_VarTraceProc for trace handles.
 */
static char *
VarTraceProc(
    ClientData clientData,	/* Widget record pointer */
    Tcl_Interp *interp, 	/* Interpreter containing variable. */
    const char *name1,		/* (unused) */
    const char *name2,		/* (unused) */
    int flags)			/* Information about what happened. */
{
    Ttk_TraceHandle *tracePtr = clientData;
    const char *name, *value;
    Tcl_Obj *valuePtr;

    if (flags & TCL_INTERP_DESTROYED) {
	return NULL;
    }












    name = Tcl_GetString(tracePtr->varnameObj);

    /*
     * If the variable is being unset, then re-establish the trace:
     */
    if (flags & TCL_TRACE_DESTROYED) {
	/*

    focus -force .top.b
    update
    event generate .top.b <space>
    update  ; # shall not trigger error  invalid command name ".top.b"
} -cleanup {
    destroy .top.b .top
} -result {}

test button-15.1 {Bug [5d991b822e]} {
    # Want this not to segfault
    set var INIT
    button .b -textvariable var
    trace add variable var unset {apply {args {
	.b configure -textvariable {}
    }}}
    pack .b
    bind .b <Configure> {unset var}
    update
    destroy .b
} {}
test button-15.2 {Bug [5d991b822e]} {
    # Want this not to leak traces
    set var INIT
    button .b -textvariable var
    trace add variable var unset {apply {args {
	.b configure -textvariable new
    }}}
    pack .b
    bind .b <Configure> {unset -nocomplain var}
    update
    destroy .b
    unset new
} {}
test button-15.3 {Bug [5d991b822e]} {
    # Want this not to leak traces
    set var INIT
    checkbutton .b -variable var
    trace add variable var unset {apply {args {
	.b configure -variable {}
    }}}
    pack .b
    bind .b <Configure> {unset var}
    update
    destroy .b
} {}


imageFinish
cleanupTests
return

# Local variables:
# mode: tcl

    destroy .e
} -body {
    catch {entry .e -textvariable thisnsdoesntexist::myvar} result1
    set result1
} -cleanup {
  destroy .e
} -result {can't trace "thisnsdoesntexist::myvar": parent namespace doesn't exist}

test entry-25.1 {Bug [5d991b822e]} {
    # Want this not to segfault, or write to variable with empty name
    set var INIT
    entry .b -textvariable var
    trace add variable var unset {apply {args {
        .b configure -textvariable {}
    }}}
    pack .b
    bind .b <Configure> {unset var}
    update
    destroy .b
    info exists {}
} 0
test entry-25.2 {Bug [5d991b822e]} {
    # Want this not to leak traces
    set var INIT
    entry .b -textvariable var
    trace add variable var unset {apply {args {
        .b configure -textvariable new
    }}}
    pack .b
    bind .b <Configure> {unset -nocomplain var}
    update
    destroy .b
    unset new
} {}


# Gathered comments about lacks
# XXX Still need to write tests for EntryBlinkProc, EntryFocusProc,
# and EntryTextVarProc.
# No tests for DisplayEntry.
# XXX Still need to write tests for EntryScanTo and EntrySelectTo.
# No tests for EventuallyRedraw

    event generate .l <1> -x 5 -y 5  ; # <<ListboxSelect>> fires
    selection clear                  ; # <<ListboxSelect>> fires again
    update
    set res
} -cleanup {
    destroy .l
} -result {{.l 0} {{} {}}}

test listbox-32.1 {Bug [5d991b822e]} {
    # Want this not to segfault, or write to variable with empty name
    set var INIT
    listbox .b -listvariable var
    trace add variable var unset {apply {args {
        .b configure -listvariable {}
    }}}
    pack .b
    bind .b <Configure> {unset var}
    update
    destroy .b
    info exists {}
} 0
test listbox-32.2 {Bug [5d991b822e]} {
    # Want this not to leak traces
    set var INIT
    listbox .b -listvariable var
    trace add variable var unset {apply {args {
        .b configure -listvariable new
    }}}
    pack .b
    bind .b <Configure> {unset -nocomplain var}
    update
    destroy .b
    unset new
} {}

resetGridInfo
deleteWindows
option clear

# cleanup
cleanupTests

    menu .m1
    set foo "hello"
    list [.m1 add checkbutton -variable foo -onvalue hello -offvalue goodbye] \
		[set foo "goodbye"] [unset foo]
} -cleanup {
	deleteWindows
} -result {{} goodbye {}}
test menu-17.6 {MenuVarProc [5d991b822e]} -setup {
	deleteWindows
} -body {
    # Want this not to crash
    menu .b
    set var INIT
    .b add checkbutton -variable var
    trace add variable var unset {apply {args {
        .b entryconfigure 1 -variable {}
    }}}
    unset var
} -cleanup {
	deleteWindows
} -result {}
test menu-17.7 {MenuVarProc [5d991b822e]} -setup {
	deleteWindows
} -body {
    # Want this not to duplicate traces
    menu .b
    set var INIT
    .b add checkbutton -variable var
    trace add variable var unset {apply {args {
        .b entryconfigure 1 -variable new
    }}}
    unset var
} -cleanup {
	deleteWindows
} -result {}


test menu-18.1 {TkActivateMenuEntry} -setup {
	deleteWindows
} -body {
    menu .m1
    .m1 add command -label "test"

    menubutton .mb
    interp hide {} .mb
    destroy .mb
    set res1 [list [winfo children .] [interp hidden]]
    set res2 [list {} $l]
    expr {$res1 eq $res2}
} -result 1

test menubutton-9.1 {Bug [5d991b822e]} {
    # Want this not to segfault, or write to variable with empty name
    unset -nocomplain {}
    set var INIT
    menubutton .b -textvariable var
    trace add variable var unset {apply {args {
        .b configure -textvariable {}
    }}}
    pack .b
    bind .b <Configure> {unset var}
    update
    destroy .b
    info exists {}
} 0
test menubutton-9.2 {Bug [5d991b822e]} {
    # Want this not to leak traces
    set var INIT
    menubutton .b -textvariable var
    trace add variable var unset {apply {args {
        .b configure -textvariable new
    }}}
    pack .b
    bind .b <Configure> {unset -nocomplain var}
    update
    destroy .b
    unset new
} {}




deleteWindows
option clear
imageFinish

} -body {
    .m configure -bd 4
    .m configure -bg #ffffff
    lindex [.m configure -bd] 4
} -cleanup {
    destroy .m
} -result {4}

test message-4.1 {Bug [5d991b822e]} {
    # Want this not to segfault, or write to variable with empty name
    unset -nocomplain {}
    set var INIT
    message .b -textvariable var
    trace add variable var unset {apply {args {
        .b configure -textvariable {}
    }}}
    pack .b
    bind .b <Configure> {unset var}
    update
    destroy .b
    info exists {}
} 0
test message-4.2 {Bug [5d991b822e]} {
    # Want this not to leak traces
    set var INIT
    message .b -textvariable var
    trace add variable var unset {apply {args {
        .b configure -textvariable new
    }}}
    pack .b
    bind .b <Configure> {unset -nocomplain var}
    update
    destroy .b
    unset new
} {}

cleanupTests
return

} -body {
    pack [scale .s]
    # non-regression test for bug [55b95f578a] - shall just not crash
    .s configure -from -6.8e99 -to 8.8e99
} -cleanup {
    destroy .s
} -result {}

test scale-22.1 {Bug [5d991b822e]} {
    # Want this not to crash
    set var INIT
    scale .b -variable var
    trace add variable var unset {apply {args {
        .b configure -variable {}
    }}}
    pack .b
    bind .b <Configure> {unset var}
    update
    destroy .b
} {}
test scale-22.2 {Bug [5d991b822e]} {
    # Want this not to leak traces
    set var INIT
    scale .b -variable var
    trace add variable var unset {apply {args {
        .b configure -variable new
    }}}
    pack .b
    bind .b <Configure> {unset -nocomplain var}
    update
    destroy .b
    unset new
} {}

option clear

# cleanup
cleanupTests
return