Don't resolve forward outgoing references in class except cython and pyi (PY-26368)

python/psi-api/src/com/jetbrains/python/psi/resolve/PyReferenceResolveProvider.java

@@ -1,18 +1,4 @@
-/*
- * Copyright 2000-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.jetbrains.python.psi.resolve;
 
 import com.intellij.openapi.extensions.ExtensionPointName;
@@ -34,4 +20,8 @@ public interface PyReferenceResolveProvider {
    */
   @NotNull
   List<RatedResolveResult> resolveName(@NotNull PyQualifiedExpression element, @NotNull TypeEvalContext context);
+
+  default boolean allowsForwardOutgoingReferencesInClass(@NotNull PyQualifiedExpression element) {
+    return false;
+  }
 }

python/src/META-INF/python-core-common.xml

@@ -712,6 +712,7 @@
     <typeProvider implementation="com.jetbrains.python.pyi.PyiTypeProvider"/>
     <pyModuleMembersProvider implementation="com.jetbrains.python.pyi.PyiModuleMembersProvider"/>
     <pyClassMembersProvider implementation="com.jetbrains.python.pyi.PyiClassMembersProvider"/>
+    <pyReferenceResolveProvider implementation="com.jetbrains.python.pyi.PyiReferenceResolveProvider"/>
     <visitorFilter language="PythonStub" implementationClass="com.jetbrains.python.pyi.PyiVisitorFilter"/>
     <inspectionExtension implementation="com.jetbrains.python.pyi.PyiInspectionExtension"/>
     <inspectionExtension implementation="com.jetbrains.python.codeInsight.typing.PyTypingInspectionExtension"/>

python/src/com/jetbrains/python/psi/impl/references/PyReferenceImpl.java

@@ -1,18 +1,4 @@
-/*
- * Copyright 2000-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.jetbrains.python.psi.impl.references;
 
 import com.google.common.collect.Lists;
@@ -297,6 +283,17 @@ public class PyReferenceImpl implements PsiReferenceEx, PsiPolyVariantReference
           }
         }
         else if (referenceOwner != null) {
+          if (!allowsForwardOutgoingReferencesInClass(myElement)) {
+            final PyClass outermostNestedClass = outermostNestedClass(referenceOwner, resolvedOwner);
+
+            if (outermostNestedClass != null) {
+              final List<Instruction> instructions =
+                PyDefUseUtil.getLatestDefs(resolvedOwner, referencedName, outermostNestedClass, false, true);
+
+              return resolveToLatestDefs(instructions, outermostNestedClass, referencedName, typeEvalContext);
+            }
+          }
+
           final Scope referenceScope = ControlFlowCache.getScope(referenceOwner);
           if (referenceScope.containsDeclaration(referencedName)) {
             unreachableLocalDeclaration = true;
@@ -360,6 +357,25 @@ public class PyReferenceImpl implements PsiReferenceEx, PsiPolyVariantReference
     return true;
   }
 
+  private static boolean allowsForwardOutgoingReferencesInClass(@NotNull PyQualifiedExpression element) {
+    return ContainerUtil.exists(Extensions.getExtensions(PyReferenceResolveProvider.EP_NAME),
+                                provider -> provider.allowsForwardOutgoingReferencesInClass(element));
+  }
+
+  @Nullable
+  private static PyClass outermostNestedClass(@NotNull ScopeOwner referenceOwner, @NotNull ScopeOwner resolvedOwner) {
+    PyClass current  = PyUtil.as(referenceOwner, PyClass.class);
+    ScopeOwner outer = ScopeUtil.getScopeOwner(current);
+
+    while (outer != resolvedOwner) {
+      current = PyUtil.as(outer, PyClass.class);
+      if (current == null) return null;
+      outer = ScopeUtil.getScopeOwner(outer);
+    }
+
+    return current;
+  }
+
   @NotNull
   private ResolveResultList resolveByOverridingReferenceResolveProviders() {
     final ResolveResultList results = new ResolveResultList();

python/src/com/jetbrains/python/pyi/PyiReferenceResolveProvider.kt

@@ -0,0 +1,16 @@
+// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.jetbrains.python.pyi
+
+import com.jetbrains.python.psi.PyQualifiedExpression
+import com.jetbrains.python.psi.resolve.PyReferenceResolveProvider
+import com.jetbrains.python.psi.resolve.RatedResolveResult
+import com.jetbrains.python.psi.types.TypeEvalContext
+
+class PyiReferenceResolveProvider: PyReferenceResolveProvider {
+
+  override fun resolveName(element: PyQualifiedExpression, context: TypeEvalContext): List<RatedResolveResult> = emptyList()
+
+  override fun allowsForwardOutgoingReferencesInClass(element: PyQualifiedExpression): Boolean {
+    return PyiUtil.isInsideStubAnnotation(element)
+  }
+}

python/testData/inspections/PyUnresolvedReferencesInspection/forwardReferencesInClassBody.py

@@ -0,0 +1,22 @@
+class A1:
+    foo = <error descr="Unresolved reference 'B1'">B1</error>()
+
+class B1:
+    pass
+
+
+class A21:
+    class A22:
+        bar = <error descr="Unresolved reference 'B2'">B2</error>()
+
+class B2:
+    pass
+
+
+class A31:
+    def baz(self):
+        class A32:
+            egg = B3()
+
+class B3:
+    pass

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

@@ -643,6 +643,11 @@ public class PyUnresolvedReferencesInspectionTest extends PyInspectionTestCase {
     doTest();
   }
 
+  // PY-26368
+  public void testForwardReferencesInClassBody() {
+    doTest();
+  }
+
   @NotNull
   @Override
   protected Class<? extends PyInspection> getInspectionClass() {