Sort NULL values like an empty string.

arg_parser/args.go

@@ -174,7 +174,7 @@ func (self *storedQueryWrapper) Eval(ctx context.Context, scope types.Scope) <-c
 		if slice.Type().Kind() == reflect.Slice {
 			for i := 0; i < slice.Len(); i++ {
 				value := slice.Index(i).Interface()
-				if !types.IsNullObject(value) {
+				if !types.IsNil(value) {
 					select {
 					case <-ctx.Done():
 						return
@@ -184,7 +184,7 @@ func (self *storedQueryWrapper) Eval(ctx context.Context, scope types.Scope) <-c
 			}
 		} else {
 			row_value := self.toRow(scope, self.value)
-			if !types.IsNullObject(row_value) {
+			if !types.IsNil(row_value) {
 				select {
 				case <-ctx.Done():
 					return
@@ -198,7 +198,7 @@ func (self *storedQueryWrapper) Eval(ctx context.Context, scope types.Scope) <-c
 }
 
 func (self *storedQueryWrapper) toRow(scope types.Scope, value types.Any) types.Row {
-	if types.IsNullObject(value) {
+	if types.IsNil(value) {
 		return types.Null{}
 	}
 

arg_parser/args_test.go

@@ -14,7 +14,6 @@ import (
 	"www.velocidex.com/golang/vfilter/arg_parser"
 	"www.velocidex.com/golang/vfilter/scope"
 	"www.velocidex.com/golang/vfilter/types"
-	"www.velocidex.com/golang/vfilter/utils"
 	"www.velocidex.com/golang/vfilter/utils/dict"
 )
 
@@ -185,7 +184,7 @@ func (self argFunc) Call(ctx context.Context, scope types.Scope, args *ordereddi
 		result.Set("dict", arg.Dict)
 	}
 
-	if !utils.IsNil(arg.Any) {
+	if !types.IsNil(arg.Any) {
 		result.Set("any", arg.Any)
 		result.Set("any type", fmt.Sprintf("%T", arg.Any))
 

arg_parser/parser.go

@@ -173,7 +173,7 @@ func sliceDictParser(ctx context.Context, scope types.Scope,
 	result := []*ordereddict.Dict{}
 	for i := 0; i < len(new_value); i++ {
 		item := new_value[i]
-		if !utils.IsNil(item) {
+		if !types.IsNil(item) {
 			result = append(result, dict.RowToDict(ctx, scope, item))
 		}
 	}
@@ -269,7 +269,7 @@ func dictParser(ctx context.Context, scope types.Scope,
 
 	// Build the query args
 	env := ordereddict.NewDict()
-	if !utils.IsNil(arg) {
+	if !types.IsNil(arg) {
 		// Shortcut for actual dicts
 		dict, ok := arg.(*ordereddict.Dict)
 		if ok {

functions/if.go

@@ -6,7 +6,6 @@ import (
 	"github.com/Velocidex/ordereddict"
 	"www.velocidex.com/golang/vfilter/arg_parser"
 	"www.velocidex.com/golang/vfilter/types"
-	"www.velocidex.com/golang/vfilter/utils"
 )
 
 type _IfFunctionArgs struct {
@@ -38,7 +37,7 @@ func (self _IfFunction) Call(
 	}
 
 	if scope.Bool(arg.Condition) {
-		if utils.IsNil(arg.Then) {
+		if types.IsNil(arg.Then) {
 			return &types.Null{}
 		}
 
@@ -63,7 +62,7 @@ func (self _IfFunction) Call(
 			return t
 		}
 	}
-	if utils.IsNil(arg.Else) {
+	if types.IsNil(arg.Else) {
 		return &types.Null{}
 	}
 

protocols/protocol_associative.go

@@ -35,7 +35,7 @@ func (self *AssociativeDispatcher) Associative(
 	scope types.Scope, a types.Any, b types.Any) (types.Any, bool) {
 	ctx := context.Background()
 
-	if utils.IsNil(a) {
+	if types.IsNil(a) {
 		return types.Null{}, false
 	}
 
@@ -79,7 +79,7 @@ func (self *AssociativeDispatcher) Associative(
 
 			// Do not let naked nils to be retrieved from
 			// a dict, instead return Null{}
-			if res == nil || utils.IsNil(res) {
+			if res == nil || types.IsNil(res) {
 				res = types.Null{}
 			}
 

protocols/protocol_eq.go

@@ -29,7 +29,7 @@ func (self EqDispatcher) Eq(scope types.Scope, a types.Any, b types.Any) bool {
 
 	switch t := a.(type) {
 	case types.Null, *types.Null, nil:
-		return types.IsNullObject(b) // types.Null == types.Null else false
+		return types.IsNil(b) // types.Null == types.Null else false
 
 	case string:
 		rhs, ok := b.(string)

protocols/protocol_iterate.go

@@ -65,7 +65,7 @@ func (self IterateDispatcher) Iterate(
 	go func() {
 		defer close(output_chan)
 
-		if !types.IsNullObject(a) {
+		if !types.IsNil(a) {
 			select {
 			case <-ctx.Done():
 				return
@@ -99,7 +99,7 @@ func _SliceIterator(ctx context.Context, scope types.Scope, a types.Any) <-chan
 		if a_value.Type().Kind() == reflect.Slice {
 			for i := 0; i < a_value.Len(); i++ {
 				value := a_value.Index(i).Interface()
-				if types.IsNullObject(value) {
+				if types.IsNil(value) {
 					continue
 				}
 

scope/marshal.go

@@ -76,7 +76,7 @@ func (self ScopeUnmarshaller) Unmarshal(
 		unmarshalled, err := unmarshaller.Unmarshal(unmarshaller,
 			new_scope, v)
 		if err == nil {
-			if !utils.IsNil(unmarshalled) {
+			if !types.IsNil(unmarshalled) {
 				env.Set(k, unmarshalled)
 			}
 		} else {

sort/sort.go

@@ -82,6 +82,16 @@ func (self *DefaultSorterCtx) Less(i, j int) bool {
 		return false
 	}
 
+	// Sort NULL like an empty string because normally NULL
+	// comparisons are not stable.
+	if types.IsNil(element1) {
+		element1 = ""
+	}
+
+	if types.IsNil(element2) {
+		element2 = ""
+	}
+
 	if self.Desc {
 		return !self.Scope.Lt(element1, element2)
 	}

types/null.go

@@ -1,5 +1,7 @@
 package types
 
+import "reflect"
+
 // A real type which encodes to JSON NULL. Using go's nil is dangerous
 // because it forces constant checking for nil pointer dereference. It
 // is safer to just return this value when VQL needs to return NULL.
@@ -13,7 +15,7 @@ func (self Null) String() string {
 	return "Null"
 }
 
-func IsNullObject(a interface{}) bool {
+func IsNil(a interface{}) bool {
 	if a == nil {
 		return true
 	}
@@ -22,6 +24,11 @@ func IsNullObject(a interface{}) bool {
 	case Null, *Null:
 		return true
 	default:
+		switch reflect.TypeOf(a).Kind() {
+		case reflect.Ptr, reflect.Map, reflect.Chan, reflect.Slice:
+			//use of IsNil method
+			return reflect.ValueOf(a).IsNil()
+		}
 		return false
 	}
 }

utils/utils.go

@@ -50,19 +50,6 @@ func IsCallable(method_value reflect.Value, field_name string) bool {
 	return true
 }
 
-func IsNil(i interface{}) bool {
-	if i == nil {
-		return true
-	}
-
-	switch reflect.TypeOf(i).Kind() {
-	case reflect.Ptr, reflect.Map, reflect.Chan, reflect.Slice:
-		//use of IsNil method
-		return reflect.ValueOf(i).IsNil()
-	}
-	return false
-}
-
 func InString(hay *[]string, needle string) bool {
 	for _, x := range *hay {
 		if x == needle {

vfilter.go

@@ -1783,7 +1783,7 @@ func (self *_SymbolRef) callFunction(
 
 	// Do not allow nil in VQL since it is not compatible with
 	// reflect package. The VQL plugin might accidentally pass nil
-	if utils.IsNil(result) {
+	if types.IsNil(result) {
 		return &Null{}
 	}