Fix highlighting classes that use 'Final' classes as metaclasses (PEP 591) (PY-34945)

GitOrigin-RevId: dce7e7f371a46f00b0e6847b417a477842d4e709

python/src/com/jetbrains/python/inspections/PyFinalInspection.kt

@@ -30,11 +30,11 @@ class PyFinalInspection : PyInspection() {
     override fun visitPyClass(node: PyClass) {
       super.visitPyClass(node)
 
-      node.superClassExpressions.forEach {
-        val cls = (myTypeEvalContext.getType(it) as? PyClassType)?.pyClass
-        if (cls != null && isFinal(cls)) {
-          registerProblem(it, "'${cls.name}' is marked as '@final' and should not be subclassed")
-        }
+      node.getSuperClasses(myTypeEvalContext).filter { isFinal(it) }.let { finalSuperClasses ->
+        if (finalSuperClasses.isEmpty()) return@let
+
+        val postfix = " ${if (finalSuperClasses.size == 1) "is" else "are"} marked as '@final' and should not be subclassed"
+        registerProblem(node.nameIdentifier, finalSuperClasses.joinToString(postfix = postfix) { "'${it.name}'" ?: "" })
       }
 
       if (PyiUtil.isInsideStub(node)) {

python/testData/inspections/PyFinalInspection/SubclassingFinalClass/a.py

@@ -1,3 +1,3 @@
 from b import A
-class B(<warning descr="'A' is marked as '@final' and should not be subclassed">A</warning>):
+class <warning descr="'A' is marked as '@final' and should not be subclassed">B</warning>(A):
     pass

python/testSrc/com/jetbrains/python/inspections/PyFinalInspectionTest.java

@@ -16,8 +16,33 @@ public class PyFinalInspectionTest extends PyInspectionTestCase {
                  "@final\n" +
                  "class A:\n" +
                  "    pass\n" +
-                 "class B(<warning descr=\"'A' is marked as '@final' and should not be subclassed\">A</warning>):\n" +
+                 "class <warning descr=\"'A' is marked as '@final' and should not be subclassed\">B</warning>(A):\n" +
                  "    pass");
+
+    doTestByText("from typing_extensions import final\n" +
+                 "@final\n" +
+                 "class A:\n" +
+                 "    pass\n" +
+                 "@final\n" +
+                 "class B:\n" +
+                 "    pass\n" +
+                 "class <warning descr=\"'A', 'B' are marked as '@final' and should not be subclassed\">C</warning>(A, B):\n" +
+                 "    pass");
+  }
+
+  // PY-34945
+  public void testFinalClassAsMetaclass() {
+    runWithLanguageLevel(
+      LanguageLevel.PYTHON30,
+      () -> doTestByText("from typing_extensions import final\n" +
+                         "\n" +
+                         "@final\n" +
+                         "class MT(type):\n" +
+                         "    pass\n" +
+                         "\n" +
+                         "class A(metaclass=MT):\n" +
+                         "    pass")
+    );
   }
 
   // PY-34945
@@ -416,7 +441,7 @@ public class PyFinalInspectionTest extends PyInspectionTestCase {
                          "    <warning descr=\"'a' is 'Final' and could not be reassigned\">a</warning> = 2")
     );
   }
-  
+
   // PY-34945
   public void testNonLocalReassignment() {
     runWithLanguageLevel(