Fix for types and namespaces with the same fullName. Fix for anonymous namespaces. Renamed namespace suffix to <extension> as this is what they actually represent.

Author: max-leuthaeuser

joern-cli/frontends/c2cpg/src/main/scala/io/joern/c2cpg/astcreation/AstCreatorHelper.scala

@@ -67,13 +67,18 @@ trait AstCreatorHelper { this: AstCreator =>
   }
 
   protected def scopeLocalUniqueNamespaceFullName(fullName: String): String = {
-    scopeLocalUniqueNames.get(fullName) match {
+    val newFullName = fullName match {
+      case ""     => "<namespace>"
+      case s"$p." => s"$p.<namespace>"
+      case other  => other
+    }
+    scopeLocalUniqueNames.get(newFullName) match {
       case None =>
-        scopeLocalUniqueNames.update(fullName, 0)
-        fullName
+        scopeLocalUniqueNames.update(newFullName, 0)
+        newFullName
       case Some(index) =>
-        val suffix = s"${Defines.DuplicateSuffix}$index"
-        s"$fullName$suffix"
+        val suffix = s"${Defines.NamespaceExtension}$index"
+        s"$newFullName$suffix"
     }
   }
 

joern-cli/frontends/c2cpg/src/main/scala/io/joern/c2cpg/astcreation/Defines.scala

@@ -23,6 +23,7 @@ object Defines {
   val OperatorCall: String                   = "<operator>()"
   val OperatorNew: String                    = "<operator>.new"
   val DuplicateSuffix                        = "<duplicate>"
+  val NamespaceExtension                     = "<extension>"
   val ConstSuffix                            = "<const>"
   val GlobalTag                              = "<global>"
   val UnknownTag                             = "<unknown>"

joern-cli/frontends/c2cpg/src/main/scala/io/joern/c2cpg/astcreation/FullNameProvider.scala

@@ -22,6 +22,7 @@ object FullNameProvider {
     "<const>",
     "<duplicate>",
     "<enum>",
+    "<extension>",
     "<global>",
     "<iterator>",
     "<lambda>",

joern-cli/frontends/c2cpg/src/main/scala/io/joern/c2cpg/astcreation/TypeNameProvider.scala

@@ -179,11 +179,12 @@ trait TypeNameProvider { this: AstCreator =>
         val (uniqueName, uniqueNameFullName) = scopeLocalUniqueName(name_, fullName_, "enum")
         TypeFullNameInfo(uniqueName, uniqueNameFullName)
       case n: ICPPASTNamespaceDefinition =>
-        val name_     = shortName(n)
+        val name = shortName(n) match {
+          case ""    => "<namespace>"
+          case other => other
+        }
         val fullName_ = fullName(n)
-        val (uniqueName, uniqueNameFullName) =
-          scopeLocalUniqueName(name_, fullName_, "namespace")
-        TypeFullNameInfo(uniqueName, scopeLocalUniqueNamespaceFullName(uniqueNameFullName))
+        TypeFullNameInfo(name, scopeLocalUniqueNamespaceFullName(fullName_))
       case s: IASTCompositeTypeSpecifier =>
         val fullName_ = registerType(cleanType(fullName(s)))
         val name_ = shortName(s) match {

joern-cli/frontends/c2cpg/src/test/scala/io/joern/c2cpg/cpp/features17/Cpp17FeaturesTests.scala

@@ -320,6 +320,26 @@ class Cpp17FeaturesTests extends AstC2CpgSuite(fileSuffix = FileDefaults.CppExt)
       )
     }
 
+    "handle namespaces and classes with the same name" in {
+      val cpg = code("""
+          |namespace A {
+          |  class A {}
+          |}
+          |
+          |namespace A {
+          |  class B {}
+          |}
+          |""".stripMargin)
+      cpg.namespaceBlock.nameNot("<global>").name.sorted shouldBe Seq("A", "A")
+      cpg.namespaceBlock.nameNot("<global>").fullName.sorted shouldBe Seq("Test0.cpp:A", "Test0.cpp:A<extension>0")
+
+      cpg.typeDecl.nameNot("<global>").name.sorted shouldBe Seq("A", "B")
+
+      // We get these fullNames directly from CDT, so they do not include the filename prefix.
+      // Classes in anonymous namespaces have no fullName prefix at all according to the CDT fullName resolution.
+      cpg.typeDecl.nameNot("<global>").fullName.sorted shouldBe Seq("A.A", "A.B")
+    }
+
     "handle the same namespace appearing multiple times in the same file" in {
       val cpg = code("""
           |namespace A { // old
@@ -351,8 +371,10 @@ class Cpp17FeaturesTests extends AstC2CpgSuite(fileSuffix = FileDefaults.CppExt)
           |}
           |""".stripMargin)
       cpg.namespaceBlock.nameNot("<global>").name.sorted shouldBe Seq(
-        "<namespace>0",
-        "<namespace>1",
+        // Within a translation unit each unnamed namespace definition maps to the same unique name:
+        // multiple unnamed namespace definitions in the same scope denote the same unnamed namespace
+        "<namespace>",
+        "<namespace>",
         "A",
         "A",
         "B",
@@ -363,16 +385,16 @@ class Cpp17FeaturesTests extends AstC2CpgSuite(fileSuffix = FileDefaults.CppExt)
         "X"
       )
       cpg.namespaceBlock.nameNot("<global>").fullName.sorted shouldBe Seq(
-        "Test0.cpp:<namespace>0",
-        "Test0.cpp:<namespace>1",
+        "Test0.cpp:<namespace>",
+        "Test0.cpp:<namespace><extension>0",
         "Test0.cpp:A",
         "Test0.cpp:A.B",
         "Test0.cpp:A.B.C",
-        "Test0.cpp:A.B.C<duplicate>0",
-        "Test0.cpp:A.B<duplicate>0",
-        "Test0.cpp:A<duplicate>0",
+        "Test0.cpp:A.B.C<extension>0",
+        "Test0.cpp:A.B<extension>0",
+        "Test0.cpp:A<extension>0",
         "Test0.cpp:X",
-        "Test0.cpp:X<duplicate>0"
+        "Test0.cpp:X<extension>0"
       )
       cpg.typeDecl.nameNot("<global>").name.sorted shouldBe Seq(
         "Bar",

joern-cli/frontends/c2cpg/src/test/scala/io/joern/c2cpg/passes/types/NamespaceTypeTests.scala

@@ -119,9 +119,9 @@ class NamespaceTypeTests extends C2CpgSuite(fileSuffix = FileDefaults.CppExt) {
         |  j++;    // ok, increments ::A::(unique)::j
         |}""".stripMargin)
       inside(cpg.namespaceBlock.nameNot("<global>").sortBy(_.fullName).l) { case List(unnamed1, namespaceA, unnamed2) =>
-        unnamed1.fullName shouldBe "Test0.cpp:<namespace>0"
+        unnamed1.fullName shouldBe "Test0.cpp:<namespace>"
         namespaceA.fullName shouldBe "Test0.cpp:A"
-        unnamed2.fullName shouldBe "Test0.cpp:A.<namespace>0"
+        unnamed2.fullName shouldBe "Test0.cpp:A.<namespace>"
       }
 
       inside(cpg.method.internal.nameNot("<global>").fullName.l) { case List(f, g, h) =>
@@ -195,7 +195,7 @@ class NamespaceTypeTests extends C2CpgSuite(fileSuffix = FileDefaults.CppExt) {
         |}""".stripMargin)
       inside(cpg.namespaceBlock.nameNot("<global>").l) { case List(a1, a2) =>
         a1.fullName shouldBe "Test0.cpp:A"
-        a2.fullName shouldBe "Test0.cpp:A<duplicate>0"
+        a2.fullName shouldBe "Test0.cpp:A<extension>0"
       }
 
       inside(cpg.method.internal.nameNot("<global>").l) { case List(foo, bar, f1, f2) =>