From a719a82ae48d3c2ba6840ae227555427ef5cada0 Mon Sep 17 00:00:00 2001
From: Bas Leijdekkers <basleijdekkers@gmail.com>
Date: Tue, 19 Jul 2022 11:05:10 +0200
Subject: [PATCH] java inspections: implement preview for quick fix

GitOrigin-RevId: d2930f7ddab6bf3d761b20b1759ff83f0cc06605
---
 ...ossibleHeapPollutionVarargsInspection.java | 22 ++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/PossibleHeapPollutionVarargsInspection.java b/java/java-analysis-impl/src/com/intellij/codeInspection/PossibleHeapPollutionVarargsInspection.java
index 66e855375358..12ccc102a2ae 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/PossibleHeapPollutionVarargsInspection.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/PossibleHeapPollutionVarargsInspection.java
@@ -1,10 +1,11 @@
-// 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.
+// Copyright 2000-2022 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.codeInspection;
 
 import com.intellij.codeInsight.AnnotationUtil;
 import com.intellij.codeInsight.daemon.impl.analysis.GenericsHighlightUtil;
 import com.intellij.codeInsight.daemon.impl.analysis.JavaGenericsUtil;
 import com.intellij.codeInsight.intention.AddAnnotationPsiFix;
+import com.intellij.codeInsight.intention.preview.IntentionPreviewInfo;
 import com.intellij.java.analysis.JavaAnalysisBundle;
 import com.intellij.openapi.command.WriteCommandAction;
 import com.intellij.openapi.diagnostic.Logger;
@@ -68,6 +69,10 @@ public class PossibleHeapPollutionVarargsInspection extends AbstractBaseJavaLoca
 
     @Override
     public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
+      applyFix(project, descriptor, true);
+    }
+
+    private void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor, boolean writeCommand) {
       final PsiElement psiElement = descriptor.getPsiElement();
       if (!(psiElement instanceof PsiIdentifier)) return;
       PsiModifierListOwner owner = (PsiModifierListOwner)psiElement.getParent();
@@ -77,13 +82,24 @@ public class PossibleHeapPollutionVarargsInspection extends AbstractBaseJavaLoca
         String compactCtorText = "public " + rec.getName() + " {}";
         PsiMethod ctor = JavaPsiFacade.getElementFactory(project).createMethodFromText(compactCtorText, owner);
         PsiMethod firstMethod = ArrayUtil.getFirstElement(rec.getMethods());
-        owner = (PsiMethod)WriteCommandAction.writeCommandAction(owner.getContainingFile()).withName(getFamilyName())
-          .compute(() -> rec.addBefore(ctor, firstMethod));
+        if (writeCommand) {
+          owner = (PsiMethod)WriteCommandAction.writeCommandAction(owner.getContainingFile()).withName(getFamilyName())
+            .compute(() -> rec.addBefore(ctor, firstMethod));
+        }
+        else {
+          owner = (PsiMethod)rec.addBefore(ctor, firstMethod);
+        }
       }
       if (owner instanceof PsiMethod) {
         new AddAnnotationPsiFix(CommonClassNames.JAVA_LANG_SAFE_VARARGS, owner).applyFix(project, descriptor);
       }
     }
+
+    @Override
+    public @NotNull IntentionPreviewInfo generatePreview(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
+      applyFix(project, descriptor, false);
+      return IntentionPreviewInfo.DIFF;
+    }
   }
 
   private static class MakeFinalAndAnnotateQuickFix extends AddAnnotationPsiFix {