DeleteSwitchLabelFix: delete unreachable switch branch

Fixes IDEA-199692 Quickfix to delete unreachable switch branch reported by "constant conditions & exceptions"
2026-09-27 10:03:11 +07:00 · 2018-10-01 14:54:36 +07:00
parent 27b2efd106
commit 5fc3612fa9
12 changed files with 267 additions and 5 deletions
@@ -8,10 +8,7 @@ import com.intellij.codeInsight.intention.AddAnnotationPsiFix;
 import com.intellij.codeInspection.*;
 import com.intellij.codeInspection.dataFlow.DataFlowInstructionVisitor.ConstantResult;
 import com.intellij.codeInspection.dataFlow.NullabilityProblemKind.NullabilityProblem;
-import com.intellij.codeInspection.dataFlow.fix.RedundantInstanceofFix;
-import com.intellij.codeInspection.dataFlow.fix.ReplaceWithConstantValueFix;
-import com.intellij.codeInspection.dataFlow.fix.ReplaceWithObjectsEqualsFix;
-import com.intellij.codeInspection.dataFlow.fix.SimplifyToAssignmentFix;
+import com.intellij.codeInspection.dataFlow.fix.*;
 import com.intellij.codeInspection.dataFlow.instructions.*;
 import com.intellij.codeInspection.dataFlow.value.DfaConstValue;
 import com.intellij.codeInspection.nullable.NullableStuffInspectionBase;
@@ -693,7 +690,8 @@ public class DataFlowInspectionBase extends AbstractBaseJavaLocalInspectionTool
    else if (psiAnchor instanceof PsiSwitchLabelStatement) {
      if (falseSet.contains(instruction)) {
        holder.registerProblem(psiAnchor,
-                               InspectionsBundle.message("dataflow.message.unreachable.switch.label"));
+                               InspectionsBundle.message("dataflow.message.unreachable.switch.label"),
+                               new DeleteSwitchLabelFix((PsiSwitchLabelStatement)psiAnchor));
      }
    }
    else if (psiAnchor != null && !isFlagCheck(psiAnchor)) {
@@ -0,0 +1,97 @@
+// Copyright 2000-2018 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.intellij.codeInspection.dataFlow.fix;
+
+import com.intellij.codeInspection.LocalQuickFix;
+import com.intellij.codeInspection.ProblemDescriptor;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.*;
+import com.intellij.psi.search.LocalSearchScope;
+import com.intellij.psi.search.searches.ReferencesSearch;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.util.ObjectUtils;
+import com.siyeh.ig.psiutils.CommentTracker;
+import com.siyeh.ig.psiutils.ControlFlowUtils;
+import one.util.streamex.StreamEx;
+import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Stream;
+
+public class DeleteSwitchLabelFix implements LocalQuickFix {
+  private final String myName;
+  private final boolean myBranch;
+
+  public DeleteSwitchLabelFix(PsiSwitchLabelStatement label) {
+    myName = Objects.requireNonNull(label.getCaseValue()).getText();
+    PsiStatement nextStatement = PsiTreeUtil.getNextSiblingOfType(label, PsiStatement.class);
+    if (nextStatement instanceof PsiSwitchLabelStatement) {
+      myBranch = false;
+    }
+    else {
+      PsiStatement prevStatement = PsiTreeUtil.getPrevSiblingOfType(label, PsiStatement.class);
+      myBranch = prevStatement == null || !ControlFlowUtils.statementMayCompleteNormally(prevStatement);
+    }
+  }
+
+  @Nls(capitalization = Nls.Capitalization.Sentence)
+  @NotNull
+  @Override
+  public String getName() {
+    return myBranch ?
+           "Remove switch branch '" + myName + "'" :
+           "Remove switch label '" + myName + "'";
+  }
+
+  @Nls(capitalization = Nls.Capitalization.Sentence)
+  @NotNull
+  @Override
+  public String getFamilyName() {
+    return "Remove switch label";
+  }
+
+  @Override
+  public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
+    PsiSwitchLabelStatement label = PsiTreeUtil.getNonStrictParentOfType(descriptor.getStartElement(), PsiSwitchLabelStatement.class);
+    if (label == null) return;
+    if (myBranch) {
+      PsiCodeBlock scope = ObjectUtils.tryCast(label.getParent(), PsiCodeBlock.class);
+      if (scope == null) return;
+      PsiSwitchLabelStatement nextLabel = PsiTreeUtil.getNextSiblingOfType(label, PsiSwitchLabelStatement.class);
+      PsiElement stopAt = nextLabel == null ? scope.getRBrace() : nextLabel;
+      while(true) {
+        PsiStatement next = PsiTreeUtil.getNextSiblingOfType(nextLabel, PsiStatement.class);
+        if (!(next instanceof PsiSwitchLabelStatement)) break;
+        nextLabel = (PsiSwitchLabelStatement)next;
+      }
+      int end = nextLabel == null ? -1 : nextLabel.getTextOffset();
+      List<PsiElement> toDelete = new ArrayList<>();
+      List<PsiDeclarationStatement> declarations = new ArrayList<>();
+      for (PsiElement e = label.getNextSibling(); e != stopAt; e = e.getNextSibling()) {
+        if (e instanceof PsiDeclarationStatement && nextLabel != null) {
+          PsiDeclarationStatement declaration = (PsiDeclarationStatement)e;
+          PsiElement[] elements = declaration.getDeclaredElements();
+          boolean declarationIsReused = Stream.of(elements).anyMatch(
+            element -> !ReferencesSearch.search(element, new LocalSearchScope(scope))
+              .forEach(ref -> ref.getElement().getTextOffset() < end));
+          if (declarationIsReused) {
+            StreamEx.of(elements).select(PsiVariable.class).map(PsiVariable::getInitializer).nonNull().into(toDelete);
+            declarations.add(declaration);
+            continue;
+          }
+        }
+        toDelete.add(e);
+      }
+      CommentTracker ct = new CommentTracker();
+      toDelete.stream().filter(PsiElement::isValid).forEach(ct::delete);
+      for (PsiDeclarationStatement declaration : declarations) {
+        scope.addAfter(declaration, nextLabel);
+        declaration.delete();
+      }
+      ct.insertCommentsBefore(label);
+    }
+    new CommentTracker().deleteAndRestoreComments(label);
+  }
+}
@@ -0,0 +1,16 @@
+// "Remove switch branch '"baz"'" "true"
+class Main {
+    public void test() {
+        switch ("foo") {
+            case "qux":
+            case "bar":
+                class Foo {}
+                int i;
+                i = 2;
+                System.out.println("hello"+new Foo()+i);
+                //oops
+            default:
+                System.out.println("oops");
+        }
+    }
+}
@@ -0,0 +1,19 @@
+// "Remove switch label '"qux"'" "true"
+class Main {
+    public void test() {
+        switch ("foo") {
+            case "baz":
+                int i = 1;
+                class Foo {}
+                System.out.println(i);
+                break;
+            /*comment*/
+            case "bar":
+                i = 2;
+                System.out.println("hello"+new Foo()+i);
+                //oops
+            default:
+                System.out.println("oops");
+        }
+    }
+}
@@ -0,0 +1,19 @@
+// "Remove switch label '"bar"'" "true"
+class Main {
+    public void test() {
+        switch ("foo") {
+            case "baz":
+                int i = 1;
+                class Foo {}
+                System.out.println(i);
+                break;
+            case "qux":
+                // comment
+                i = 2;
+                System.out.println("hello"+new Foo()+i);
+                //oops
+            default:
+                System.out.println("oops");
+        }
+    }
+}
@@ -0,0 +1,11 @@
+// "Remove switch branch '"bar"'" "true"
+class Main {
+    public void test() {
+        switch ("foo") {
+            case "baz":
+                System.out.println("foo");
+                break;
+            //oops
+        }
+    }
+}
@@ -0,0 +1,19 @@
+// "Remove switch branch '"baz"'" "true"
+class Main {
+    public void test() {
+        switch ("foo") {
+            case "<caret>baz":
+                int i = 1;
+                class Foo {}
+                System.out.println(i);
+                break;
+            case "qux":
+            case "bar":
+                i = 2;
+                System.out.println("hello"+new Foo()+i);
+                //oops
+            default:
+                System.out.println("oops");
+        }
+    }
+}
@@ -0,0 +1,19 @@
+// "Remove switch label '"qux"'" "true"
+class Main {
+    public void test() {
+        switch ("foo") {
+            case "baz":
+                int i = 1;
+                class Foo {}
+                System.out.println(i);
+                break;
+            case "<caret>qux" /*comment*/:
+            case "bar":
+                i = 2;
+                System.out.println("hello"+new Foo()+i);
+                //oops
+            default:
+                System.out.println("oops");
+        }
+    }
+}
@@ -0,0 +1,20 @@
+// "Remove switch label '"bar"'" "true"
+class Main {
+    public void test() {
+        switch ("foo") {
+            case "baz":
+                int i = 1;
+                class Foo {}
+                System.out.println(i);
+                break;
+            case "qux":
+            case "<caret>bar" // comment
+                :
+                i = 2;
+                System.out.println("hello"+new Foo()+i);
+                //oops
+            default:
+                System.out.println("oops");
+        }
+    }
+}
@@ -0,0 +1,15 @@
+// "Remove switch branch '"bar"'" "true"
+class Main {
+    public void test() {
+        switch ("foo") {
+            case "baz":
+                System.out.println("foo");
+                break;
+            case "<caret>bar":
+                int i = 2;
+                class Foo {}
+                System.out.println("hello"+new Foo()+i);
+                //oops
+        }
+    }
+}
@@ -0,0 +1,28 @@
+// Copyright 2000-2018 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.intellij.java.codeInsight.daemon.quickFix;
+
+import com.intellij.codeInsight.daemon.quickFix.LightQuickFixParameterizedTestCase;
+import com.intellij.codeInspection.LocalInspectionTool;
+import com.intellij.codeInspection.dataFlow.DataFlowInspection;
+import com.intellij.testFramework.LightProjectDescriptor;
+import com.intellij.testFramework.fixtures.LightCodeInsightFixtureTestCase;
+import org.jetbrains.annotations.NotNull;
+
+public class DeleteSwitchLabelFixTest extends LightQuickFixParameterizedTestCase {
+  @NotNull
+  @Override
+  protected LocalInspectionTool[] configureLocalInspectionTools() {
+    return new LocalInspectionTool[]{new DataFlowInspection()};
+  }
+
+  @NotNull
+  @Override
+  protected LightProjectDescriptor getProjectDescriptor() {
+    return LightCodeInsightFixtureTestCase.JAVA_8;
+  }
+
+  @Override
+  protected String getBasePath() {
+    return "/codeInsight/daemonCodeAnalyzer/quickFix/deleteSwitchLabel";
+  }
+}
@@ -65,6 +65,7 @@ import org.junit.runners.Suite;
  StreamFilterNotNullFixTest.class,
  RedundantInstanceofFixTest.class,
  ReplaceComputeWithComputeIfPresentFixTest.class,
+  DeleteSwitchLabelFixTest.class,
  })
 public class DataFlowInspectionTestSuite {
 }