vector.Not: Set true/null to false/null (#6471)

Closes #6431

Author: mattnibs

runtime/vam/expr/logic.go

@@ -27,8 +27,11 @@ func (n *Not) Eval(val vector.Any) vector.Any {
 func (n *Not) eval(vecs ...vector.Any) vector.Any {
 	switch vec := vecs[0].(type) {
 	case *vector.Bool:
-		return vector.NewBool(bitvec.Not(vec.Bits), vec.Nulls)
+		return vector.Not(vec)
 	case *vector.Const:
+		if vec.Value().IsNull() {
+			return vec
+		}
 		return vector.NewConst(super.NewBool(!vec.Value().Bool()), vec.Len(), vec.Nulls)
 	case *vector.Error:
 		return vec

runtime/ztests/expr/logical-not.yaml

@@ -15,3 +15,21 @@ output: |
   null::bool
   error("missing")
   error("foo")
+
+---
+
+# Ensure true/null values are converted to false/null.
+spq: |
+  values false or not this
+
+vector: true
+
+input: |
+  true
+  false
+  null::bool
+
+output: |
+  false
+  true
+  null::bool

vector/bool.go

@@ -64,6 +64,16 @@ func Or(a, b *Bool) *Bool {
 	return NewBool(bits, nulls)
 }
 
+func Not(vec *Bool) *Bool {
+	bits := bitvec.Not(vec.Bits)
+	if vec.Nulls.IsZero() {
+		return NewBool(bits, bitvec.Zero)
+	}
+	// Flip true/null values to false/null.
+	bits = bitvec.And(bits, bitvec.Not(vec.Nulls))
+	return NewBool(bits, vec.Nulls)
+}
+
 // BoolValue returns the value of slot in vec if the value is a Boolean.  It
 // returns false otherwise.
 func BoolValue(vec Any, slot uint32) (bool, bool) {