Issue checkstyle#8764: Create new check IllegalIdentifierName

config/checkstyle_checks.xml

@@ -681,6 +681,9 @@
     </module>
     <module name="TypeName"/>
     <module name="PatternVariableName"/>
+    <module name="IllegalIdentifierName">
+      <property name="format" value="(?i)^(?!(record|yield|var|open|transitive|_.+)$).+$"/>
+    </module>
 
     <!-- Regexp -->
     <module name="Regexp"/>

src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalIdentifierNameTest.java

@@ -0,0 +1,89 @@
+////////////////////////////////////////////////////////////////////////////////
+// checkstyle: Checks Java source code for adherence to a set of rules.
+// Copyright (C) 2001-2020 the original author or authors.
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+////////////////////////////////////////////////////////////////////////////////
+
+package org.checkstyle.suppressionxpathfilter;
+
+import java.io.File;
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
+import com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck;
+import com.puppycrawl.tools.checkstyle.checks.naming.IllegalIdentifierNameCheck;
+
+public class XpathRegressionIllegalIdentifierNameTest extends AbstractXpathTestSupport {
+
+    private final String checkName = IllegalIdentifierNameCheck.class.getSimpleName();
+
+    @Override
+    protected String getCheckName() {
+        return checkName;
+    }
+
+    @Test
+    public void testOne() throws Exception {
+        final File fileToProcess = new File(getNonCompilablePath(
+            "SuppressionXpathRegressionIllegalIdentifierNameTestOne.java"));
+
+        final DefaultConfiguration moduleConfig =
+            createModuleConfig(IllegalIdentifierNameCheck.class);
+
+        final String format = "(?i)^(?!(record|yield|var|_.+)$).+$";
+
+        final String[] expectedViolation = {
+            "10:20: " + getCheckMessage(IllegalIdentifierNameCheck.class,
+                AbstractNameCheck.MSG_INVALID_PATTERN, "yield", format),
+            };
+
+        final List<String> expectedXpathQueries = Collections.singletonList(
+            "/RECORD_DEF[./IDENT[@text='SuppressionXpathRegressionIllegalIdentifierNameTestOne'"
+                + "]]/RECORD_COMPONENTS/RECORD_COMPONENT_DEF/IDENT[@text='yield']"
+        );
+
+        runVerifications(moduleConfig, fileToProcess, expectedViolation,
+            expectedXpathQueries);
+    }
+
+    @Test
+    public void testTwo() throws Exception {
+        final File fileToProcess = new File(getNonCompilablePath(
+            "SuppressionXpathRegressionIllegalIdentifierNameTestTwo.java"));
+
+        final DefaultConfiguration moduleConfig =
+            createModuleConfig(IllegalIdentifierNameCheck.class);
+
+        final String format = "(?i)^(?!(record|yield|var|_.+)$).+$";
+
+        final String[] expectedViolation = {
+            "9:17: " + getCheckMessage(IllegalIdentifierNameCheck.class,
+                AbstractNameCheck.MSG_INVALID_PATTERN, "yield", format),
+            };
+
+        final List<String> expectedXpathQueries = Collections.singletonList(
+            "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionIllegalIdentifierNameTestTwo']"
+                + "]/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]/PARAMETERS/PARAMETER_DEF"
+                + "/IDENT[@text='yield']"
+        );
+
+        runVerifications(moduleConfig, fileToProcess, expectedViolation,
+            expectedXpathQueries);
+    }
+}

src/it/resources-noncompilable/org/checkstyle/suppressionxpathfilter/illegalidentifiername/SuppressionXpathRegressionIllegalIdentifierNameTestOne.java

@@ -0,0 +1,12 @@
+//non-compiled with javac: Compilable with Java14
+package org.checkstyle.suppressionxpathfilter.illegalidentifiername;
+
+/* Config:
+ *
+ * default
+ */
+public record SuppressionXpathRegressionIllegalIdentifierNameTestOne
+        (String string,
+            String yield, // warn
+            String otherString){
+}

src/it/resources-noncompilable/org/checkstyle/suppressionxpathfilter/illegalidentifiername/SuppressionXpathRegressionIllegalIdentifierNameTestTwo.java

@@ -0,0 +1,17 @@
+//non-compiled with javac: Compilable with Java14
+package org.checkstyle.suppressionxpathfilter.illegalidentifiername;
+
+/* Config:
+ *
+ * default
+ */
+public class SuppressionXpathRegressionIllegalIdentifierNameTestTwo {
+    int foo(int yield) { // warn
+        return switch (yield) {
+            case 1 -> 2;
+            case 2 -> 3;
+            case 3 -> 4;
+            default -> 5;
+        };
+    }
+}

src/main/java/com/puppycrawl/tools/checkstyle/PackageObjectFactory.java

@@ -755,6 +755,8 @@ private static void fillChecksFromNamingPackage() {
                 BASE_PACKAGE + ".checks.naming.TypeNameCheck");
         NAME_TO_FULL_MODULE_NAME.put("PatternVariableNameCheck",
                 BASE_PACKAGE + ".checks.naming.PatternVariableNameCheck");
+        NAME_TO_FULL_MODULE_NAME.put("IllegalIdentifierNameCheck",
+            BASE_PACKAGE + ".checks.naming.IllegalIdentifierNameCheck");
     }
 
     /**

src/main/java/com/puppycrawl/tools/checkstyle/checks/naming/IllegalIdentifierNameCheck.java

@@ -0,0 +1,179 @@
+////////////////////////////////////////////////////////////////////////////////
+// checkstyle: Checks Java source code for adherence to a set of rules.
+// Copyright (C) 2001-2020 the original author or authors.
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+////////////////////////////////////////////////////////////////////////////////
+
+package com.puppycrawl.tools.checkstyle.checks.naming;
+
+import com.puppycrawl.tools.checkstyle.StatelessCheck;
+import com.puppycrawl.tools.checkstyle.api.DetailAST;
+import com.puppycrawl.tools.checkstyle.api.TokenTypes;
+import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
+
+/**
+ * <p>
+ * Checks identifiers for a set of illegal names, such as those that are restricted or contextual
+ * keywords. Examples include "yield", "record", and "var". Please read more at
+ * <a href="https://docs.oracle.com/javase/specs/jls/se14/html/jls-3.html#jls-3.9">
+ * Java Language Specification</a> to get to know more about restricted keywords.
+ * </p>
+ * <ul>
+ * <li>
+ * Property {@code format} - Specifies valid identifiers.
+ * Type is {@code java.util.regex.Pattern}.
+ * Default value is {@code "(?i)^(?!(record|yield|var|_.+)$).+$"}.
+ * </li>
+ * <li>
+ * Property {@code tokens} - tokens to check
+ * Type is {@code java.lang.String[]}.
+ * Validation type is {@code tokenSet}.
+ * Default value is:
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF">
+ * CLASS_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF">
+ * INTERFACE_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF">
+ * ENUM_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_DEF">
+ * ANNOTATION_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_FIELD_DEF">
+ * ANNOTATION_FIELD_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PARAMETER_DEF">
+ * PARAMETER_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
+ * VARIABLE_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_DEF">
+ * METHOD_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_CONSTANT_DEF">
+ * ENUM_CONSTANT_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PATTERN_VARIABLE_DEF">
+ * PATTERN_VARIABLE_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF">
+ * RECORD_DEF</a>,
+ * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_COMPONENT_DEF">
+ * RECORD_COMPONENT_DEF</a>.
+ * </li>
+ * </ul>
+ * <p>
+ * To configure the check:
+ * </p>
+ * <p>Configuration:</p>
+ * <pre>
+ * &lt;module name="IllegalIdentifierName"/&gt;
+ * </pre>
+ * <p>
+ * Example:
+ * </p>
+ * <pre>
+ * public class TestClass {
+ *     public static void main(String... args) {
+ *         var var = 4; // violation, "var" should not be used as an identifier.
+ *         int record = 15; // violation, "record" should not be used as an identifier.
+ *         String yield = "yield"; // violation, "yield" should not be used as an identifier.
+ *
+ *         record Record // violation, "Record" should not be used as an idenitifier.
+ *             (Record record) { // violation, "record" should not be used as an identifier.
+ *         }
+ *
+ *         String yieldString = "yieldString"; // ok, part of another word
+ *         record MyRecord(){} // ok, part of another word
+ *         var variable = 2; // ok, part of another word
+ *         String _string; // violation, begins with underscore
+ *     }
+ * }
+ * </pre>
+ * <p>
+ * To configure the check to include "open" and "transitive" in the set of illegal identifiers:
+ * </p>
+ * <p>Configuration:</p>
+ * <pre>
+ * &lt;module name="IllegalIdentifierName"&gt;
+ *     &lt;property name="format" value="(?i)^(?!(record|yield|var|open|transitive|_.+)$).+$"/&gt;
+ * &lt;/module&gt;
+ * </pre>
+ * <p>Example:</p>
+ * <pre>
+ * public class TestClass {
+ *     public static void main(String... args) {
+ *
+ *         int open = 4; // violation, "open" should not be used as an identifier
+ *         Object transitive = "transitive"; // violation, "transitive" should not
+ *                                                // be used as an identifier
+ *
+ *         int openInt = 4; // ok, "open" is part of another word
+ *         Object transitiveObject = "transitiveObject"; // ok, "transitive" is part of another word
+ *     }
+ * }
+ * </pre>
+ * <p>
+ * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
+ * </p>
+ * <p>
+ * Violation Message Keys:
+ * </p>
+ * <ul>
+ * <li>
+ * {@code name.invalidPattern}
+ * </li>
+ * </ul>
+ *
+ * @since 8.36
+ */
+@StatelessCheck
+public class IllegalIdentifierNameCheck extends AbstractNameCheck {
+
+    /**
+     * Creates a new {@code IllegalIdentifierNameCheck} instance.
+     */
+    public IllegalIdentifierNameCheck() {
+        super("(?i)^(?!(record|yield|var|_.+)$).+$");
+    }
+
+    @Override
+    public int[] getDefaultTokens() {
+        return getAcceptableTokens();
+    }
+
+    @Override
+    public int[] getAcceptableTokens() {
+        return new int[] {
+            TokenTypes.CLASS_DEF,
+            TokenTypes.INTERFACE_DEF,
+            TokenTypes.ENUM_DEF,
+            TokenTypes.ANNOTATION_DEF,
+            TokenTypes.ANNOTATION_FIELD_DEF,
+            TokenTypes.PARAMETER_DEF,
+            TokenTypes.VARIABLE_DEF,
+            TokenTypes.METHOD_DEF,
+            TokenTypes.ENUM_CONSTANT_DEF,
+            TokenTypes.PATTERN_VARIABLE_DEF,
+            TokenTypes.RECORD_DEF,
+            TokenTypes.RECORD_COMPONENT_DEF,
+        };
+    }
+
+    @Override
+    public int[] getRequiredTokens() {
+        return CommonUtil.EMPTY_INT_ARRAY;
+    }
+
+    @Override
+    protected boolean mustCheckName(DetailAST ast) {
+        return ast.findFirstToken(TokenTypes.IDENT) != null;
+    }
+
+}

src/main/resources/com/puppycrawl/tools/checkstyle/meta/checks/naming/IllegalIdentifierNameCheck.xml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<checkstyle-metadata>
+   <module>
+      <check fully-qualified-name="com.puppycrawl.tools.checkstyle.checks.naming.IllegalIdentifierNameCheck"
+             name="IllegalIdentifierName"
+             parent="com.puppycrawl.tools.checkstyle.TreeWalker">
+         <description>&lt;p&gt;
+ Checks identifiers for a set of illegal names, such as those that are restricted or contextual
+ keywords. Examples include "yield", "record", and "var". Please read more at
+ &lt;a href="https://docs.oracle.com/javase/specs/jls/se14/html/jls-3.html#jls-3.9"&gt;
+ Java Language Specification&lt;/a&gt; to get to know more about restricted keywords.
+ &lt;/p&gt;</description>
+         <properties>
+            <property default-value="(?i)^(?!(record|yield|var|_.+)$).+$"
+                      name="format"
+                      type="java.util.regex.Pattern">
+               <description>Specifies valid identifiers.</description>
+            </property>
+            <property default-value="CLASS_DEF,INTERFACE_DEF,ENUM_DEF,ANNOTATION_DEF,ANNOTATION_FIELD_DEF,PARAMETER_DEF,VARIABLE_DEF,METHOD_DEF,ENUM_CONSTANT_DEF,PATTERN_VARIABLE_DEF,RECORD_DEF,RECORD_COMPONENT_DEF"
+                      name="tokens"
+                      type="java.lang.String[]"
+                      validation-type="tokenSet">
+               <description>tokens to check</description>
+            </property>
+         </properties>
+         <message-keys>
+            <message-key key="name.invalidPattern"/>
+         </message-keys>
+      </check>
+   </module>
+</checkstyle-metadata>