extract method: copy parameters annotations to the extracted method when applicable (IDEA-40617)

java/java-impl/src/com/intellij/refactoring/extractMethod/ExtractMethodProcessor.java

@@ -1137,6 +1137,7 @@ public class ExtractMethodProcessor implements MatchProvider {
     for (VariableData data : myVariableDatum) {
       if (data.passAsParameter) {
         PsiParameter parm = myElementFactory.createParameter(data.name, data.type);
+        copyParamAnnotations(parm);
         if (isFinal) {
           PsiUtil.setModifierProperty(parm, PsiModifier.FINAL, true);
         }
@@ -1171,6 +1172,21 @@ public class ExtractMethodProcessor implements MatchProvider {
     return (PsiMethod)myStyleManager.reformat(newMethod);
   }
 
+  private void copyParamAnnotations(PsiParameter parm) {
+    final PsiVariable variable = PsiResolveHelper.SERVICE.getInstance(myProject).resolveReferencedVariable(parm.getName(), myElements[0]);
+    if (variable instanceof PsiParameter) {
+      final PsiModifierList modifierList = variable.getModifierList();
+      if (modifierList != null) {
+        for (PsiAnnotation annotation : modifierList.getAnnotations()) {
+          if (SuppressWarnings.class.getName().equals(annotation.getQualifiedName())) continue;
+          final PsiModifierList parmModifierList = parm.getModifierList();
+          LOG.assertTrue(parmModifierList != null, parm);
+          parmModifierList.add(annotation);
+        }
+      }
+    }
+  }
+
   @NotNull
   protected PsiMethodCallExpression generateMethodCall(PsiExpression instanceQualifier, final boolean generateArgs) throws IncorrectOperationException {
     @NonNls StringBuilder buffer = new StringBuilder();

java/java-tests/testData/refactoring/extractMethod/CopyParamAnnotations.java

@@ -0,0 +1,21 @@
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+class X {
+  @NotNull
+  public X fun1(int x) {
+    return this;
+  }
+
+  public X fun2(@Nullable @SuppressWarnings("unused") String b) {
+    <selection>
+    if (b != null) {
+      int x = 1;
+      return fun1(x);
+    }
+    </selection>
+
+    int x = 0;
+    return null;
+  }
+}

java/java-tests/testData/refactoring/extractMethod/CopyParamAnnotations_after.java

@@ -0,0 +1,28 @@
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+class X {
+  @NotNull
+  public X fun1(int x) {
+    return this;
+  }
+
+  public X fun2(@Nullable @SuppressWarnings("unused") String b) {
+
+      X x1 = newMethod(b);
+      if (x1 != null) return x1;
+
+
+      int x = 0;
+    return null;
+  }
+
+    @Nullable
+    private X newMethod(@Nullable String b) {
+        if (b != null) {
+          int x = 1;
+          return fun1(x);
+        }
+        return null;
+    }
+}

java/java-tests/testSrc/com/intellij/refactoring/ExtractMethodTest.java

@@ -611,6 +611,10 @@ public class ExtractMethodTest extends LightCodeInsightTestCase {
     doTest();
   }
 
+  public void testCopyParamAnnotations() throws Exception {
+    doTest();
+  }
+
   private void doTestDisabledParam() throws PrepareFailedException {
     final CodeStyleSettings settings = CodeStyleSettingsManager.getSettings(getProject());
     settings.ELSE_ON_NEW_LINE = true;