Update overriding method with overloads (PY-30287)

* Select implementation as super method, not an overload
* Copy all its overloads
* Add imports for decorators (e.g. typing.overload)

python/src/com/jetbrains/python/codeInsight/override/PyOverrideImplementUtil.java

@@ -27,6 +27,7 @@ import com.jetbrains.python.psi.impl.PyFunctionBuilder;
 import com.jetbrains.python.psi.impl.PyPsiUtils;
 import com.jetbrains.python.psi.resolve.PyResolveContext;
 import com.jetbrains.python.psi.types.*;
+import com.jetbrains.python.pyi.PyiUtil;
 import com.jetbrains.python.refactoring.classes.PyClassRefactoringUtil;
 import one.util.streamex.StreamEx;
 import org.jetbrains.annotations.NotNull;
@@ -157,12 +158,7 @@ public class PyOverrideImplementUtil {
 
     PyFunction element = null;
     for (PyMethodMember newMember : Lists.reverse(newMembers)) {
-      final PyFunction baseFunction = (PyFunction)newMember.getPsiElement();
-      final PyFunctionBuilder builder = buildOverriddenFunction(pyClass, baseFunction, implement);
-      final PyFunction function = builder.addFunctionAfter(statementList, anchor);
-
-      addImports(baseFunction, function);
-      element = CodeInsightUtilCore.forcePsiPostprocessAndRestoreElement(function);
+      element = writeMember(pyClass, (PyFunction)newMember.getPsiElement(), anchor, implement);
     }
 
     PyPsiUtils.removeRedundantPass(statementList);
@@ -175,6 +171,29 @@ public class PyOverrideImplementUtil {
     }
   }
 
+  @Nullable
+  private static PyFunction writeMember(@NotNull PyClass cls,
+                                        @NotNull PyFunction baseFunction,
+                                        @Nullable PsiElement anchor,
+                                        boolean implement) {
+    final PyStatementList statementList = cls.getStatementList();
+    final TypeEvalContext context = TypeEvalContext.userInitiated(cls.getProject(), cls.getContainingFile());
+
+    final PyFunction function = buildOverriddenFunction(cls, baseFunction, implement).addFunctionAfter(statementList, anchor);
+    addImports(baseFunction, function, context);
+
+    PyiUtil
+      .getOverloads(baseFunction, context)
+      .forEach(
+        baseOverload -> {
+          final PyFunction overload = (PyFunction)statementList.addBefore(baseOverload, function);
+          addImports(baseOverload, overload, context);
+        }
+      );
+
+    return CodeInsightUtilCore.forcePsiPostprocessAndRestoreElement(function);
+  }
+
   private static PyFunctionBuilder buildOverriddenFunction(PyClass pyClass,
                                                            PyFunction baseFunction,
                                                            boolean implement) {
@@ -352,8 +371,10 @@ public class PyOverrideImplementUtil {
       if (type != null) {
         for (PyFunction function : PyTypeUtil.getMembersOfType(type, PyFunction.class, false, context)) {
           final String name = function.getName();
-          if (name != null && !functions.containsKey(name)) {
-            functions.put(name, function);
+          if (name != null) {
+            if (!functions.containsKey(name) || PyiUtil.isOverload(functions.get(name), context) && !PyiUtil.isOverload(function, context)) {
+              functions.put(name, function);
+            }
           }
         }
       }
@@ -362,22 +383,19 @@ public class PyOverrideImplementUtil {
   }
 
   /**
-   * Adds imports for type hints in overridden function (PY-18553).
+   * Adds imports for type hints and decorators in overridden function.
    *
    * @param baseFunction base function used to resolve types
    * @param function overridden function
    */
-  private static void addImports(@NotNull PyFunction baseFunction, @NotNull PyFunction function) {
-    final TypeEvalContext typeEvalContext = TypeEvalContext.userInitiated(baseFunction.getProject(), baseFunction.getContainingFile());
-
+  private static void addImports(@NotNull PyFunction baseFunction, @NotNull PyFunction function, @NotNull TypeEvalContext context) {
     final UnresolvedExpressionVisitor unresolvedExpressionVisitor = new UnresolvedExpressionVisitor();
-    final List<PyAnnotation> annotations = getAnnotations(function, typeEvalContext);
-    annotations.forEach(annotation -> unresolvedExpressionVisitor.visitPyElement(annotation));
-    final List<PyReferenceExpression> unresolved = unresolvedExpressionVisitor.getUnresolved();
+    getAnnotations(function, context).forEach(annotation -> annotation.accept(unresolvedExpressionVisitor));
+    getDecorators(function).forEach(decorator -> decorator.accept(unresolvedExpressionVisitor));
 
-    final ResolveExpressionVisitor resolveExpressionVisitor = new ResolveExpressionVisitor(unresolved);
-    final List<PyAnnotation> baseAnnotations = getAnnotations(baseFunction, typeEvalContext);
-    baseAnnotations.forEach(annotation -> resolveExpressionVisitor.visitPyElement(annotation));
+    final ResolveExpressionVisitor resolveExpressionVisitor = new ResolveExpressionVisitor(unresolvedExpressionVisitor.getUnresolved());
+    getAnnotations(baseFunction, context).forEach(annotation -> annotation.accept(resolveExpressionVisitor));
+    getDecorators(baseFunction).forEach(decorator -> decorator.accept(resolveExpressionVisitor));
   }
 
   /**
@@ -387,6 +405,7 @@ public class PyOverrideImplementUtil {
    * @param typeEvalContext
    * @return
    */
+  @NotNull
   private static List<PyAnnotation> getAnnotations(@NotNull PyFunction function, @NotNull TypeEvalContext typeEvalContext) {
     return StreamEx.of(function.getParameters(typeEvalContext))
         .map(PyCallableParameter::getParameter)
@@ -398,6 +417,12 @@ public class PyOverrideImplementUtil {
         .toList();
   }
 
+  @NotNull
+  private static List<PyDecorator> getDecorators(@NotNull PyFunction function) {
+    final PyDecoratorList decoratorList = function.getDecoratorList();
+    return decoratorList == null ? Collections.emptyList() : Arrays.asList(decoratorList.getDecorators());
+  }
+
   /**
    * Collects unresolved {@link PyReferenceExpression} objects.
    */

python/testData/override/methodWithOverloadsInAnotherFile.py

@@ -0,0 +1,4 @@
+from methodWithOverloadsInAnotherFile_parent import Foo
+
+class B(Foo):
+    <caret>pass

python/testData/override/methodWithOverloadsInAnotherFile_after.py

@@ -0,0 +1,14 @@
+from typing import overload
+
+from methodWithOverloadsInAnotherFile_parent import Foo
+
+class B(Foo):
+    @overload
+    def fun(self, s:str) -> str: pass
+
+    @overload
+    def fun(self, i:int) -> int: pass
+
+    def fun(self, x):
+        super().fun(x)
+

python/testData/override/methodWithOverloadsInAnotherFile_parent.py

@@ -0,0 +1,11 @@
+from typing import overload
+
+class Foo(object):
+    @overload
+    def fun(self, s:str) -> str: pass
+
+    @overload
+    def fun(self, i:int) -> int: pass
+
+    def fun(self, x):
+        pass

python/testData/override/methodWithOverloadsInTheSameFile.py

@@ -0,0 +1,14 @@
+from typing import overload
+
+class Foo:
+    @overload
+    def fun(self, s:str) -> str: pass
+
+    @overload
+    def fun(self, i:int) -> int: pass
+
+    def fun(self, x):
+        pass
+
+class B(Foo):
+    <caret>pass

python/testData/override/methodWithOverloadsInTheSameFile_after.py

@@ -0,0 +1,22 @@
+from typing import overload
+
+class Foo:
+    @overload
+    def fun(self, s:str) -> str: pass
+
+    @overload
+    def fun(self, i:int) -> int: pass
+
+    def fun(self, x):
+        pass
+
+class B(Foo):
+    @overload
+    def fun(self, s:str) -> str: pass
+
+    @overload
+    def fun(self, i:int) -> int: pass
+
+    def fun(self, x):
+        super().fun(x)
+

python/testSrc/com/jetbrains/python/PyOverrideTest.java

@@ -4,6 +4,7 @@
 package com.jetbrains.python;
 
 import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiFile;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.util.containers.ContainerUtil;
 import com.jetbrains.python.codeInsight.override.PyMethodMember;
@@ -228,4 +229,45 @@ public class PyOverrideTest extends PyTestCase {
   public void testAsyncMethod() {
     runWithLanguageLevel(LanguageLevel.PYTHON36, () -> doTest());
   }
+
+  // PY-30287
+  public void testMethodWithOverloadsInTheSameFile() {
+    runWithLanguageLevel(
+      LanguageLevel.PYTHON35,
+      () -> {
+        myFixture.configureByFile("override/" + getTestName(true) + ".py");
+
+        PyOverrideImplementUtil.overrideMethods(
+          myFixture.getEditor(),
+          getTopLevelClass(1),
+          Collections.singletonList(new PyMethodMember(getTopLevelClass(0).getMethods()[2])),
+          false
+        );
+
+        myFixture.checkResultByFile("override/" + getTestName(true) + "_after.py", true);
+      }
+    );
+  }
+
+  // PY-30287
+  public void testMethodWithOverloadsInAnotherFile() {
+    runWithLanguageLevel(
+      LanguageLevel.PYTHON35,
+      () -> {
+        final PsiFile[] files = myFixture.configureByFiles(
+          "override/" + getTestName(true) + ".py",
+          "override/" + getTestName(true) + "_parent.py"
+        );
+
+        PyOverrideImplementUtil.overrideMethods(
+          myFixture.getEditor(),
+          getTopLevelClass(0),
+          Collections.singletonList(new PyMethodMember(((PyFile)files[1]).getTopLevelClasses().get(0).getMethods()[2])),
+          false
+        );
+
+        myFixture.checkResultByFile("override/" + getTestName(true) + "_after.py", true);
+      }
+    );
+  }
 }