From 4aef4a880a54cfa7a9c5d6400602c1b27d2226a5 Mon Sep 17 00:00:00 2001 From: markiewb Date: Fri, 2 Jan 2015 14:15:59 +0100 Subject: [PATCH] Issue #44: Detect dead instanceof-expressions https://github.com/markiewb/nb-additional-hints/issues/44 --- .../hints/structure/WarnOfDeadInstanceOf.java | 115 ++++++++++++++++++ .../structure/WarnOfDeadInstanceOfTest.java | 42 +++++++ .../java/example/DeadInstanceOfExample.java | 15 +++ 3 files changed, 172 insertions(+) create mode 100644 src/main/java/de/markiewb/netbeans/plugins/hints/structure/WarnOfDeadInstanceOf.java create mode 100644 src/test/java/de/markiewb/netbeans/plugins/hints/structure/WarnOfDeadInstanceOfTest.java create mode 100644 src/test/java/example/DeadInstanceOfExample.java diff --git a/src/main/java/de/markiewb/netbeans/plugins/hints/structure/WarnOfDeadInstanceOf.java b/src/main/java/de/markiewb/netbeans/plugins/hints/structure/WarnOfDeadInstanceOf.java new file mode 100644 index 0000000..7e3cdca --- /dev/null +++ b/src/main/java/de/markiewb/netbeans/plugins/hints/structure/WarnOfDeadInstanceOf.java @@ -0,0 +1,115 @@ +/* + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. + * + * Copyright 2014 Oracle and/or its affiliates. All rights reserved. + * + * Oracle and Java are registered trademarks of Oracle and/or its affiliates. + * Other names may be trademarks of their respective owners. + * + * The contents of this file are subject to the terms of either the GNU + * General Public License Version 2 only ("GPL") or the Common + * Development and Distribution License("CDDL") (collectively, the + * "License"). You may not use this file except in compliance with the + * License. You can obtain a copy of the License at + * http://www.netbeans.org/cddl-gplv2.html + * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the + * specific language governing permissions and limitations under the + * License. When distributing the software, include this License Header + * Notice in each file and include the License file at + * nbbuild/licenses/CDDL-GPL-2-CP. Oracle designates this + * particular file as subject to the "Classpath" exception as provided + * by Oracle in the GPL Version 2 section of the License file that + * accompanied this code. If applicable, add the following below the + * License Header, with the fields enclosed by brackets [] replaced by + * your own identifying information: + * "Portions Copyrighted [year] [name of copyright owner]" + * + * If you wish your version of this file to be governed by only the CDDL + * or only the GPL Version 2, indicate your decision by adding + * "[Contributor] elects to include this software in this distribution + * under the [CDDL or GPL Version 2] license." If you do not indicate a + * single choice of license, a recipient has the option to distribute + * your version of this file under either the CDDL, the GPL Version 2 or + * to extend the choice of license to its licensees as provided above. + * However, if you add GPL Version 2 code and therefore, elected the GPL + * Version 2 license, then the option applies only if the new code is + * made subject to such option by the copyright holder. + * + * Contributor(s): + * + * Portions Copyrighted 2014 Sun Microsystems, Inc. + * Portions Copyrighted 2014 benno.markiewicz@googlemail.com + */ +package de.markiewb.netbeans.plugins.hints.structure; + +import com.sun.source.tree.InstanceOfTree; +import com.sun.source.tree.Tree; +import com.sun.source.util.TreePath; +import javax.lang.model.element.Element; +import javax.lang.model.element.TypeElement; +import javax.lang.model.type.DeclaredType; +import javax.lang.model.type.TypeKind; +import javax.lang.model.type.TypeMirror; +import org.netbeans.api.java.source.CompilationInfo; +import org.netbeans.spi.editor.hints.ErrorDescription; +import org.netbeans.spi.editor.hints.Severity; +import org.netbeans.spi.java.hints.ErrorDescriptionFactory; +import org.netbeans.spi.java.hints.Hint; +import org.netbeans.spi.java.hints.HintContext; +import org.netbeans.spi.java.hints.TriggerTreeKind; +import org.openide.util.NbBundle; + +/** + * Detects instanceof-expressions, which will never be true. + * + * https://github.com/markiewb/nb-additional-hints/issues/44 + * + * Code has been adopted from + * {@link org.netbeans.modules.java.hints.IllegalInstanceOf} + * + * @author markiewb + */ +@NbBundle.Messages({ + "# {0} - first argument in instanceof operator", + "# {1} - second argument in instanceof operator", + "ERR_WarnOfDeadInstanceOf=Dead instanceof. {0} cannot be assigned to {1}", + "DN_WarnOfDeadInstanceOf=Dead instanceof", + "DESC_WarnOfDeadInstanceOf=Detects instanceof-expressions, which will never be true.

For example: new ArrayList() instanceof java.util.Set will be never be true.

Provided by nb-additional-hints plugin

"}) +public class WarnOfDeadInstanceOf { + + @Hint(displayName = "#DN_WarnOfDeadInstanceOf", description = "#DESC_WarnOfDeadInstanceOf", category = "bugs", + hintKind = Hint.Kind.INSPECTION, severity = Severity.WARNING) + @TriggerTreeKind({Tree.Kind.INSTANCE_OF}) + public static ErrorDescription convert(HintContext ctx) { + + TreePath path = ctx.getPath(); + TreePath treePath = ctx.getPath(); + CompilationInfo info = ctx.getInfo(); + + InstanceOfTree iot = (InstanceOfTree) treePath.getLeaf(); + TypeMirror leftTypeMirror = info.getTrees().getTypeMirror(new TreePath(treePath, iot.getExpression())); + + if (leftTypeMirror == null || leftTypeMirror.getKind() != TypeKind.DECLARED) { + return null; + } + + Element leftType = ((DeclaredType) leftTypeMirror).asElement(); + Element rightType = info.getTrees().getElement(new TreePath(treePath, iot.getType())); + + if (leftType == null || rightType == null) { + //we cannot handle this + return null; + } + + final TypeMirror leftT = info.getTypes().erasure(((TypeElement) leftType).asType()); + final TypeMirror rightT = info.getTypes().erasure(((TypeElement) rightType).asType()); + //f.e. (new ArrayList() instanceof java.util.Set) is impossible + final boolean assignable = info.getTypes().isAssignable(leftT, rightT); + if (!assignable) { + return ErrorDescriptionFactory.forName(ctx, path, Bundle.ERR_WarnOfDeadInstanceOf(leftType.getSimpleName().toString(), rightType.getSimpleName().toString())); + } + + return null; + + } +} diff --git a/src/test/java/de/markiewb/netbeans/plugins/hints/structure/WarnOfDeadInstanceOfTest.java b/src/test/java/de/markiewb/netbeans/plugins/hints/structure/WarnOfDeadInstanceOfTest.java new file mode 100644 index 0000000..db9cf87 --- /dev/null +++ b/src/test/java/de/markiewb/netbeans/plugins/hints/structure/WarnOfDeadInstanceOfTest.java @@ -0,0 +1,42 @@ +package de.markiewb.netbeans.plugins.hints.structure; + +import org.junit.Test; +import org.netbeans.modules.java.hints.test.api.HintTest; + +public class WarnOfDeadInstanceOfTest { + + @Test + public void testMatchingCases() throws Exception { + /** + * 
+         * //negative cases -> error hint for instance of
+         * if (new java.util.ArrayList() instanceof java.util.Map) {}
+         * if (new java.util.ArrayList() instanceof java.util.Set) {}
+         * if (new java.util.ArrayList() instanceof java.util.Set) {}
+         * //positive cases
+         * if (new java.util.ArrayList() instanceof java.util.List) {}
+         * if (new java.util.HashSet() instanceof java.util.Set) {}
+         * if (new java.util.HashSet() instanceof java.util.Set) {}
+         *
+ */ + HintTest.create() + .input( + "package example;\n" + + "public class Test {\n" + + " void getMember(){\n" + + " //negative cases -> error hint for instance of\n" + + " if (new java.util.ArrayList() instanceof java.util.Map) {}\n" + + " if (new java.util.ArrayList() instanceof java.util.Set) {}\n" + + " if (new java.util.ArrayList() instanceof java.util.Set) {}\n" + + " //positive cases\n" + + " if (new java.util.ArrayList() instanceof java.util.List) {}\n" + + " if (new java.util.HashSet() instanceof java.util.Set) {}\n" + + " if (new java.util.HashSet() instanceof java.util.Set) {}\n" + + " };\n" + + "}" + ) + .run(WarnOfDeadInstanceOf.class) + .assertWarnings("4:13-4:63:warning:" + Bundle.ERR_WarnOfDeadInstanceOf("ArrayList", "Map"), "5:13-5:63:warning:" + Bundle.ERR_WarnOfDeadInstanceOf("ArrayList", "Set"), "6:13-6:71:warning:" + Bundle.ERR_WarnOfDeadInstanceOf("ArrayList", "Set")); + } + +} diff --git a/src/test/java/example/DeadInstanceOfExample.java b/src/test/java/example/DeadInstanceOfExample.java new file mode 100644 index 0000000..461a2ac --- /dev/null +++ b/src/test/java/example/DeadInstanceOfExample.java @@ -0,0 +1,15 @@ +package example; + +public class DeadInstanceOfExample { + + public void test() { + //negative cases -> error hint for instance of + if (new java.util.ArrayList() instanceof java.util.Map) {} + if (new java.util.ArrayList() instanceof java.util.Set) {} + if (new java.util.ArrayList() instanceof java.util.Set) {} + //positive cases + if (new java.util.ArrayList() instanceof java.util.List) {} + if (new java.util.HashSet() instanceof java.util.Set) {} + if (new java.util.HashSet() instanceof java.util.Set) {} + } +}