Support for @DynamicAttrs annotation in the docstring of a class (PY-4600)

python/src/com/jetbrains/python/inspections/PyUnresolvedReferencesInspection.java

@@ -658,14 +658,9 @@ public class PyUnresolvedReferencesInspection extends PyInspection {
         if (hasUnresolvedAncestors(cls)) {
           return true;
         }
-        if (cls.getDecoratorList() != null) {
+        if (isDecoratedAsDynamic(cls, true)) {
           return true;
         }
-        for (PyClass base : cls.iterateAncestorClasses()) {
-          if (base.getDecoratorList() != null) {
-            return true;
-          }
-        }
       }
       if (qtype instanceof CythonBuiltinType ||
           (qtype instanceof CythonType && reference instanceof PyOperatorReference)) {
@@ -680,6 +675,29 @@ public class PyUnresolvedReferencesInspection extends PyInspection {
       return false;
     }
 
+    private static boolean isDecoratedAsDynamic(@NotNull PyClass cls, boolean inherited) {
+      if (inherited) {
+        if (isDecoratedAsDynamic(cls, false)) {
+          return true;
+        }
+        for (PyClass base : cls.iterateAncestorClasses()) {
+          if (base != null && isDecoratedAsDynamic(base, false)) {
+            return true;
+          }
+        }
+      }
+      else {
+        if (cls.getDecoratorList() != null) {
+          return true;
+        }
+        final String docString = cls.getDocStringValue();
+        if (docString != null && docString.indexOf("@DynamicAttrs") != -1) {
+          return true;
+        }
+      }
+      return false;
+    }
+
     private static boolean hasUnresolvedAncestors(PyClass cls) {
       for (PyClassRef classRef : cls.iterateAncestors()) {
         if (classRef.getPyClass() == null && classRef.getType() == null) {

python/testData/inspections/PyUnresolvedReferencesInspection/dynamicAttrsAnnotation.py

@@ -0,0 +1,26 @@
+class B(object):
+    def foo(self):
+        pass
+
+
+class C(object):
+    """
+    @DynamicAttrs
+    """
+    def bar(self):
+        pass
+
+
+class D(C):
+    def baz(self):
+        pass
+
+
+b = B()
+b.foo(), b.<warning descr="Unresolved attribute reference 'spam' for class 'B'">spam</warning>()
+
+c = C()
+c.bar(), c.spam()
+
+d = D()
+d.bar(), d.baz(), d.spam(), d.eggs()

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

@@ -237,6 +237,11 @@ public class PyUnresolvedReferencesInspectionTest extends PyTestCase {
     doTest();
   }
 
+  // PY-4600
+  public void testDynamicAttrsAnnotation() {
+    doTest();
+  }
+
   private void doTest() {
     myFixture.configureByFile(TEST_DIRECTORY + getTestName(true) + ".py");
     myFixture.enableInspections(PyUnresolvedReferencesInspection.class);