Ignore unresolved __attrs_attrs__ for attrs (PY-29929)

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

@@ -2,12 +2,16 @@
 package com.jetbrains.python.inspections
 
 import com.intellij.util.containers.ContainerUtil
+import com.jetbrains.python.codeInsight.stdlib.PyDataclassParameters
+import com.jetbrains.python.codeInsight.stdlib.parseDataclassParameters
 import com.jetbrains.python.psi.PyElement
 import com.jetbrains.python.psi.PyExpression
 import com.jetbrains.python.psi.PyFunction
 import com.jetbrains.python.psi.PyUtil
 import com.jetbrains.python.psi.resolve.PyResolveContext
 import com.jetbrains.python.psi.resolve.QualifiedNameFinder
+import com.jetbrains.python.psi.types.PyClassType
+import com.jetbrains.python.psi.types.PyType
 import com.jetbrains.python.psi.types.TypeEvalContext
 
 class PyThirdPartyInspectionExtension : PyInspectionExtension() {
@@ -29,6 +33,12 @@ class PyThirdPartyInspectionExtension : PyInspectionExtension() {
     return false
   }
 
+  override fun ignoreUnresolvedMember(type: PyType, name: String, context: TypeEvalContext): Boolean {
+    return name == "__attrs_attrs__" &&
+           type is PyClassType &&
+           parseDataclassParameters(type.pyClass, context)?.type == PyDataclassParameters.Type.ATTRS
+  }
+
   private fun resolvesTo(expression: PyExpression, qualifiedName: String, resolveContext: PyResolveContext): Boolean {
     return ContainerUtil.exists(PyUtil.multiResolveTopPriority(expression, resolveContext)) {
       it is PyElement && QualifiedNameFinder.getQualifiedName(it) == qualifiedName

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

@@ -770,6 +770,18 @@ public class PyUnresolvedReferencesInspectionTest extends PyInspectionTestCase {
                  "print(<error descr=\"Unresolved reference 'module'\">module</error>)");
   }
 
+  // PY-29929
+  public void testAttrsSpecialAttribute() {
+    doTestByText("import attr\n" +
+                 "\n" +
+                 "@attr.s\n" +
+                 "class C:\n" +
+                 "    a = attr.ib()\n" +
+                 "\n" +
+                 "print(C.__attrs_attrs__)\n" +
+                 "print(C(1).__attrs_attrs__)");
+  }
+
   // PY-32927
   public void testPrefixExpressionOnClassHavingSkeletons() {
     doMultiFileTest();