Handle subset that is false

Author: kevin-dp

packages/db/src/query/predicate-utils.ts

@@ -66,6 +66,13 @@ function isWhereSubsetInternal(
   subset: BasicExpression<boolean>,
   superset: BasicExpression<boolean>
 ): boolean {
+  // If subset is false it is requesting no data,
+  // thus the result set is empty
+  // and the empty set is a subset of any set
+  if (subset.type === `val` && subset.value === false) {
+    return true
+  }
+
   // If expressions are structurally equal, subset relationship holds
   if (areExpressionsEqual(subset, superset)) {
     return true

packages/db/tests/predicate-utils.test.ts

@@ -96,6 +96,12 @@ describe(`isWhereSubset`, () => {
         isWhereSubset(gt(ref(`age`), val(10)), gt(ref(`age`), val(10)))
       ).toBe(true)
     })
+
+    it(`should return true when subset is false`, () => {
+      // When subset is false the result will always be the empty set
+      // and the empty set is a subset of any set
+      expect(isWhereSubset(val(false), gt(ref(`age`), val(10)))).toBe(true)
+    })
   })
 
   describe(`comparison operators`, () => {