change filter generation logic for types whose parent is type relation (#272)

Co-authored-by: aakash.sorathiya <aakash.sorathiya@infosys.com>

Author: AakashSorathiya

core/src/main/kotlin/org/neo4j/graphql/handler/projection/ProjectionBase.kt

@@ -178,6 +178,14 @@ open class ProjectionBase(
             if (value !is Map<*, *>) {
                 throw IllegalArgumentException("Only object values are supported for filtering on queried relation ${predicate.value}, but got ${value.javaClass.name}")
             }
+            if(type.isRelationType()) {
+                val targetNode = predicate.relNode.named(normalizeName(propertyContainer.requiredSymbolicName.value, predicate.relationshipInfo.typeName))
+                val relType = predicate.relationshipInfo.type
+                val parsedQuery2 = parseFilter(value, relType)
+                val condition = handleQuery(targetNode.requiredSymbolicName.value, "", targetNode, parsedQuery2, relType, variables)
+                result = result.and(condition)
+                continue
+            }
 
             val cond = name(normalizeName(variablePrefix, predicate.relationshipInfo.typeName, "Cond"))
             when (predicate.op) {

core/src/test/resources/filter-tests.adoc

@@ -15,13 +15,24 @@ type Person {
   fun: Boolean
   gender: Gender
   company: Company @relation(name:"WORKS_AT")
+  skills: [PersonSkills]
   location: _Neo4jPoint
 }
 type Company {
   _id: ID
   name: String
   employees: [Person] @relation(name:"WORKS_AT", direction: IN)
 }
+type Skill {
+  id: ID!
+  name: String
+  skilledPerson: [Person] @relation(name: "HAS_SKILL", direction: OUT)
+}
+type PersonSkills @relation(name: "HAS_SKILL", from: "person", to: "skill") {
+    person: Person
+    skill: Skill
+    proficiencyLevel: Int
+}
 ----
 
 == Test Data
@@ -3261,6 +3272,44 @@ RETURN p {
 
 '''
 
+=== Filter object whose parent is relationship
+
+.GraphQL-Query
+[source,graphql]
+----
+{ person { skills(filter: {skill: {name_starts_with: "F"}}) { skill { name } proficiencyLevel }}}
+----
+
+.Cypher Params
+[source,json]
+----
+{
+  "personSkillsSkillNameStartsWith" : "F"
+}
+----
+
+.Cypher
+[source,cypher]
+----
+MATCH (person:Person)
+CALL {
+	WITH person
+	MATCH (person)-[personSkills:HAS_SKILL]->(personSkillsSkill:Skill)
+	WHERE personSkillsSkill.name STARTS WITH $personSkillsSkillNameStartsWith
+	RETURN collect(personSkills {
+		skill: personSkillsSkill {
+			.name
+		},
+		.proficiencyLevel
+	}) AS personSkills
+}
+RETURN person {
+	skills: personSkills
+} AS person
+----
+
+'''
+
 === Cascaded filter object string _eq_
 
 .GraphQL-Query