fix - correct typeFullName for member with generic type, issue 105 (#2797)

* fix - correct typeFullName for member with generic type, issue 105

* PR comments for Issue no 105

Author: khemrajrathore

joern-cli/frontends/javasrc2cpg/src/main/scala/io/joern/javasrc2cpg/passes/AstCreator.scala

@@ -726,11 +726,33 @@ class AstCreator(filename: String, javaParserAst: CompilationUnit, global: Globa
   private def astForFieldVariable(v: VariableDeclarator, fieldDeclaration: FieldDeclaration): Ast = {
     // TODO: Should be able to find expected type here
     val annotations = fieldDeclaration.getAnnotations
-    val typeFullName =
-      typeInfoCalc
-        .fullName(v.getType)
-        .orElse(scopeStack.lookupVariableType(v.getTypeAsString, wildcardFallback = true))
-        .getOrElse(s"${Defines.UnresolvedNamespace}.${v.getTypeAsString}")
+
+    // variable can be declared with generic type, so we need to get rid of the <> part of it to get the package information
+    // and append the <> when forming the typeFullName again
+    // Ex - private Consumer<String, Integer> consumer;
+    // From Consumer<String, Integer> we need to get to Consumer so splitting it by '<' and then combining with '<' to
+    // form typeFullName as Consumer<String, Integer>
+
+    val typeFullNameWithoutGenericSplit = typeInfoCalc
+      .fullName(v.getType)
+      .orElse(scopeStack.lookupVariableType(v.getTypeAsString, wildcardFallback = true))
+      .getOrElse(s"${Defines.UnresolvedNamespace}.${v.getTypeAsString}")
+    val typeFullName = {
+      // Check if the typeFullName is unresolved and if it has generic information to resolve the typeFullName
+      if (
+        typeFullNameWithoutGenericSplit
+          .contains(Defines.UnresolvedNamespace) && v.getTypeAsString.contains(Defines.LeftAngularBracket)
+      ) {
+        val splitByLeftAngular = v.getTypeAsString.split(Defines.LeftAngularBracket)
+        scopeStack.lookupVariableType(splitByLeftAngular.head, wildcardFallback = true) match {
+          case Some(fullName) =>
+            fullName + splitByLeftAngular
+              .slice(1, splitByLeftAngular.size)
+              .mkString(Defines.LeftAngularBracket, Defines.LeftAngularBracket, "")
+          case None => typeFullNameWithoutGenericSplit
+        }
+      } else typeFullNameWithoutGenericSplit
+    }
     val name           = v.getName.toString
     val node           = memberNode(v, name, s"$typeFullName $name", typeFullName)
     val memberAst      = Ast(node)

joern-cli/frontends/javasrc2cpg/src/test/scala/io/joern/javasrc2cpg/querying/MemberTests.scala

@@ -20,6 +20,35 @@ class NewMemberTests extends JavaSrcCode2CpgFixture {
     cpg.member.name("x").astChildren.size shouldBe 0
   }
 
+  "member with generic class" should {
+    val cpg = code("""
+        |import org.apache.kafka.clients.consumer.Consumer;
+        |public class CountryPopulationConsumer {
+        |
+        | private Consumer<String, Integer> consumer;
+        |
+        |  void foo() {
+        |   consumer.poll(1000);
+        |  }
+        |}""".stripMargin)
+
+    "have a resolved typeFullName" in {
+      cpg.member
+        .name("consumer")
+        .typeFullName
+        .head shouldBe "org.apache.kafka.clients.consumer.Consumer<String,Integer>"
+    }
+
+    "have a resolved package name in methodFullName" in {
+      cpg
+        .call("poll")
+        .methodFullName
+        .head
+        .split(":")
+        .head shouldBe "org.apache.kafka.clients.consumer.Consumer<String,Integer>.poll"
+    }
+  }
+
   "enum entries with anonymous classes should not result in subtrees to the member node" in {
     val cpg = code("""
         |enum Foo {

joern-cli/frontends/x2cpg/src/main/scala/io/joern/x2cpg/Defines.scala

@@ -25,4 +25,6 @@ object Defines {
   // In some languages like Javascript dynamic calls do not provide any statically known
   // method/function interface information. In those cases please use this value.
   val DynamicCallUnknownFullName = "<unknownFullName>"
+
+  val LeftAngularBracket = "<"
 }