fix: Add check to filter result for logical ops (#2573)

## Relevant issue(s)

Resolves #2571

## Description

This PR adds a check post doc filtering in the fetcher to see if we need
to rely on the external conditions instead to ensure a valid filtering
operation. This is specially important when filtering with logical
operators `_and` and `_or`.

planner/filter/complex.go

@@ -17,7 +17,7 @@ import (
 
 // IsComplex returns true if the provided filter is complex.
 // A filter is considered complex if it contains a relation
-// object withing an _or or _not operator not necessarily being
+// object withing an _or, _and or _not operator not necessarily being
 // its direct  child.
 func IsComplex(filter *mapper.Filter) bool {
 	if filter == nil {
@@ -31,8 +31,11 @@ func isComplex(conditions any, seekRelation bool) bool {
 	case map[connor.FilterKey]any:
 		for k, v := range typedCond {
 			if op, ok := k.(*mapper.Operator); ok {
-				if (op.Operation == request.FilterOpOr && len(v.([]any)) > 1) ||
-					op.Operation == request.FilterOpNot {
+				switch op.Operation {
+				case request.FilterOpOr, request.FilterOpAnd, request.FilterOpNot:
+					if v, ok := v.([]any); ok && len(v) == 1 {
+						continue
+					}
 					if isComplex(v, true) {
 						return true
 					}

planner/filter/complex_test.go

@@ -109,7 +109,7 @@ func TestIsComplex(t *testing.T) {
 					m("published", m("rating", m("_gt", 4.0))),
 				),
 			),
-			isComplex: false,
+			isComplex: true,
 		},
 		{
 			name: "relation inside _and and _or",

planner/type_join.go

@@ -345,7 +345,7 @@ func prepareScanNodeFilterForTypeJoin(
 			parent.filter.Conditions = filter.Merge(
 				parent.filter.Conditions, scan.filter.Conditions)
 		}
-		filter.RemoveField(scan.filter, subType.Field)
+		scan.filter = nil
 	} else {
 		var parentFilter *mapper.Filter
 		scan.filter, parentFilter = filter.SplitByFields(scan.filter, subType.Field)

tests/integration/query/one_to_one/with_filter_test.go

@@ -492,3 +492,130 @@ func TestQueryOneToOneWithCompoundOrFilterThatIncludesRelation(t *testing.T) {
 
 	testUtils.ExecuteTestCase(t, test)
 }
+
+func TestQueryOneToOne_WithCompoundFiltersThatIncludesRelation_ShouldReturnResults(t *testing.T) {
+	test := testUtils.TestCase{
+		Description: "One-to-one relation with _and filter that includes relation",
+		Actions: []any{
+			testUtils.SchemaUpdate{
+				Schema: bookAuthorGQLSchema,
+			},
+			testUtils.CreateDoc{
+				CollectionID: 0,
+				// bae-fd541c25-229e-5280-b44b-e5c2af3e374d
+				Doc: `{
+					"name": "Painted House",
+					"rating": 4.9
+				}`,
+			},
+			testUtils.CreateDoc{
+				CollectionID: 0,
+				// bae-437092f3-7817-555c-bf8a-cc1c5a0a0db6
+				Doc: `{
+					"name": "Some Book",
+					"rating": 4.0
+				}`,
+			},
+			testUtils.CreateDoc{
+				CollectionID: 0,
+				// bae-66ba0c48-4984-5b44-83dd-edb791a54b7d
+				Doc: `{
+					"name": "Some Other Book",
+					"rating": 3.0
+				}`,
+			},
+			testUtils.CreateDoc{
+				CollectionID: 1,
+				// bae-3bfe0092-e31f-5ebe-a3ba-fa18fac448a6
+				Doc: `{
+					"name": "John Grisham",
+					"age": 65,
+					"verified": true,
+					"published_id": "bae-fd541c25-229e-5280-b44b-e5c2af3e374d"
+				}`,
+			},
+			testUtils.CreateDoc{
+				CollectionID: 1,
+				// bae-5dac8488-0f75-5ddf-b08b-804b3d33a239
+				Doc: `{
+					"name": "Some Writer",
+					"age": 45,
+					"verified": false,
+					"published_id": "bae-437092f3-7817-555c-bf8a-cc1c5a0a0db6"
+				}`,
+			},
+			testUtils.CreateDoc{
+				CollectionID: 1,
+				// bae-8b0c345b-dda7-573c-b5f1-5fa1d70593e1
+				Doc: `{
+					"name": "Some Other Writer",
+					"age": 30,
+					"verified": true,
+					"published_id": "bae-66ba0c48-4984-5b44-83dd-edb791a54b7d"
+				}`,
+			},
+			testUtils.Request{
+				Request: `query {
+					Book(filter: {_or: [
+						{rating: {_gt: 4.0}},
+						{author: {age: {_eq: 30}}}
+					]}) {
+						name
+						rating
+					}
+				}`,
+				Results: []map[string]any{
+					{
+						"name":   "Some Other Book",
+						"rating": 3.0,
+					},
+					{
+						"name":   "Painted House",
+						"rating": 4.9,
+					},
+				},
+			},
+			testUtils.Request{
+				Request: `query {
+					Book(filter: {_and: [
+						{rating: {_ge: 4.0}},
+						{author: {age: {_eq: 45}}}
+					]}) {
+						name
+						rating
+					}
+				}`,
+				Results: []map[string]any{
+					{
+						"name":   "Some Book",
+						"rating": 4.0,
+					},
+				},
+			},
+			testUtils.Request{
+				// This is the same as {_not: {_and: [{rating: {_ge: 4.0}}, {author: {age: {_eq: 45}}}]}}
+				Request: `query {
+					Book(filter: {_not: {
+						rating: {_ge: 4.0},
+						author: {age: {_eq: 45}}
+					}}) {
+						name
+						rating
+					}
+				}`,
+				Results: []map[string]any{
+					{
+						"name":   "Some Other Book",
+						"rating": 3.0,
+					},
+					{
+						"name":   "Painted House",
+						"rating": 4.9,
+					},
+				},
+			},
+		},
+	}
+
+	testUtils.ExecuteTestCase(t, test)
+}