Fix #4893 - throw if language is not supported

pmd-core/src/main/java/net/sourceforge/pmd/AbstractConfiguration.java

@@ -89,6 +89,7 @@ public abstract class AbstractConfiguration {
             throw new IllegalArgumentException(
                 "Language '" + language.getId() + "' is not registered in " + getLanguageRegistry());
         }
+        checkLanguageIsAcceptable(language);
     }
 
     public LanguageRegistry getLanguageRegistry() {
@@ -167,6 +168,8 @@ public abstract class AbstractConfiguration {
      * @param lang A language
      */
     public void setOnlyRecognizeLanguage(Language lang) {
+        AssertionUtil.requireParamNotNull("language", lang);
+        checkLanguageIsRegistered(lang);
         this.languageVersionDiscoverer.onlyRecognizeLanguages(LanguageRegistry.singleton(lang));
     }
 
@@ -177,6 +180,8 @@ public abstract class AbstractConfiguration {
      */
     public void setDefaultLanguageVersion(LanguageVersion languageVersion) {
         Objects.requireNonNull(languageVersion);
+        checkLanguageIsRegistered(languageVersion.getLanguage());
+
         languageVersionDiscoverer.setDefaultLanguageVersion(languageVersion);
         getLanguageProperties(languageVersion.getLanguage()).setLanguageVersion(languageVersion.getVersion());
     }
@@ -194,6 +199,14 @@ public abstract class AbstractConfiguration {
         }
     }
 
+    /**
+     * Check that it is correct to use the given language with this configuration.
+     * Throw if not.
+     */
+    protected void checkLanguageIsAcceptable(Language lang) {
+        // do nothing
+    }
+
     /**
      * Get the LanguageVersion of the source file with given name. This depends
      * on the fileName extension, and the java version.

pmd-core/src/main/java/net/sourceforge/pmd/PMDConfiguration.java

@@ -24,6 +24,7 @@ import net.sourceforge.pmd.internal.util.ClasspathClassLoader;
 import net.sourceforge.pmd.lang.Language;
 import net.sourceforge.pmd.lang.LanguageRegistry;
 import net.sourceforge.pmd.lang.LanguageVersion;
+import net.sourceforge.pmd.lang.PmdCapableLanguage;
 import net.sourceforge.pmd.lang.rule.RulePriority;
 import net.sourceforge.pmd.lang.rule.RuleSetLoader;
 import net.sourceforge.pmd.renderers.Renderer;
@@ -472,4 +473,12 @@ public class PMDConfiguration extends AbstractConfiguration {
     public void setReportFile(Path reportFile) {
         this.reportFile = reportFile;
     }
+
+    @Override
+    protected void checkLanguageIsAcceptable(Language lang) {
+        if (!(lang instanceof PmdCapableLanguage)) {
+            throw new UnsupportedOperationException("Language " + lang.getId() + " does not support analysis with PMD and cannot be used in a PMDConfiguration. " +
+                "You may be able to use it with CPD though.");
+        }
+    }
 }

pmd-core/src/main/java/net/sourceforge/pmd/cpd/CPDConfiguration.java

@@ -20,11 +20,12 @@ import org.slf4j.LoggerFactory;
 
 import net.sourceforge.pmd.AbstractConfiguration;
 import net.sourceforge.pmd.cpd.internal.CpdLanguagePropertiesDefaults;
+import net.sourceforge.pmd.lang.Language;
 import net.sourceforge.pmd.lang.LanguageRegistry;
+import net.sourceforge.pmd.lang.PmdCapableLanguage;
 import net.sourceforge.pmd.util.log.internal.SimpleMessageReporter;
 
 /**
- *
  * @author Brian Remedios
  * @author Romain Pelisse - <belaran@gmail.com>
  */
@@ -268,4 +269,13 @@ public class CPDConfiguration extends AbstractConfiguration {
         this.failOnViolation = failOnViolation;
     }
 
+    @Override
+    protected void checkLanguageIsAcceptable(Language lang) {
+        if (!(lang instanceof CpdCapableLanguage)) {
+            throw new UnsupportedOperationException("Language " + lang.getId() + " does not support analysis with CPD and cannot be used in a CPDConfiguration. " +
+                "You may be able to use it with PMD though.");
+        }
+    }
+
+
 }

pmd-core/src/main/java/net/sourceforge/pmd/lang/LanguageRegistry.java

@@ -35,7 +35,8 @@ public final class LanguageRegistry implements Iterable<Language> {
 
     private static final Logger LOG = LoggerFactory.getLogger(LanguageRegistry.class);
 
-    private static final LanguageRegistry ALL_LANGUAGES =
+    // test only
+    static final LanguageRegistry ALL_LANGUAGES =
         loadLanguages(LanguageRegistry.class.getClassLoader());
 
     /**

pmd-core/src/test/java/net/sourceforge/pmd/PmdConfigurationTest.java

@@ -12,6 +12,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.File;
@@ -30,6 +31,9 @@ import org.junit.jupiter.api.io.TempDir;
 import net.sourceforge.pmd.cache.internal.FileAnalysisCache;
 import net.sourceforge.pmd.cache.internal.NoopAnalysisCache;
 import net.sourceforge.pmd.internal.util.ClasspathClassLoader;
+import net.sourceforge.pmd.lang.CpdOnlyDummyLanguage;
+import net.sourceforge.pmd.lang.DummyLanguageModule;
+import net.sourceforge.pmd.lang.LanguageRegistry;
 import net.sourceforge.pmd.lang.rule.RulePriority;
 import net.sourceforge.pmd.renderers.CSVRenderer;
 import net.sourceforge.pmd.renderers.Renderer;
@@ -230,4 +234,14 @@ class PmdConfigurationTest {
         configuration.setIgnoreIncrementalAnalysis(true);
         assertTrue(configuration.getAnalysisCache() instanceof NoopAnalysisCache, "Ignoring incremental analysis should turn the cache into a noop");
     }
+
+    @Test
+    void testCpdOnlyLanguage() {
+        final PMDConfiguration configuration = new PMDConfiguration(LanguageRegistry.CPD);
+
+        assertThrows(UnsupportedOperationException.class,
+            () -> configuration.setOnlyRecognizeLanguage(CpdOnlyDummyLanguage.getInstance()));
+       assertThrows(UnsupportedOperationException.class,
+            () -> configuration.setDefaultLanguageVersion(CpdOnlyDummyLanguage.getInstance().getDefaultVersion()));
+    }
 }

pmd-core/src/test/java/net/sourceforge/pmd/cpd/CPDConfigurationTest.java

@@ -9,6 +9,7 @@ import static org.hamcrest.Matchers.instanceOf;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
@@ -16,6 +17,9 @@ import java.util.Map;
 
 import org.junit.jupiter.api.Test;
 
+import net.sourceforge.pmd.lang.DummyLanguageNoCapabilities;
+import net.sourceforge.pmd.lang.LanguageRegistry;
+
 class CPDConfigurationTest {
 
     @Test
@@ -59,4 +63,16 @@ class CPDConfigurationTest {
         assertEquals(StandardCharsets.UTF_16.name(), ((XMLRenderer) renderer).getEncoding());
     }
 
+
+    @Test
+    void testCpdNotSupported() {
+        DummyLanguageNoCapabilities lang = DummyLanguageNoCapabilities.getInstance();
+        final CPDConfiguration configuration = new CPDConfiguration(LanguageRegistry.singleton(lang));
+
+        assertThrows(UnsupportedOperationException.class,
+            () -> configuration.setOnlyRecognizeLanguage(lang));
+        assertThrows(UnsupportedOperationException.class,
+            () -> configuration.setDefaultLanguageVersion(lang.getDefaultVersion()));
+    }
+
 }

pmd-core/src/test/java/net/sourceforge/pmd/lang/CpdOnlyDummyLanguage.java

@@ -0,0 +1,47 @@
+/**
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+package net.sourceforge.pmd.lang;
+
+import java.util.Objects;
+
+import net.sourceforge.pmd.cpd.AnyCpdLexer;
+import net.sourceforge.pmd.cpd.CpdCapableLanguage;
+import net.sourceforge.pmd.cpd.CpdLanguageProperties;
+import net.sourceforge.pmd.cpd.CpdLexer;
+import net.sourceforge.pmd.lang.ast.DummyNode;
+import net.sourceforge.pmd.lang.ast.DummyNode.DummyRootNode;
+import net.sourceforge.pmd.lang.ast.ParseException;
+import net.sourceforge.pmd.lang.ast.Parser;
+import net.sourceforge.pmd.lang.ast.Parser.ParserTask;
+import net.sourceforge.pmd.lang.document.Chars;
+import net.sourceforge.pmd.lang.document.TextDocument;
+import net.sourceforge.pmd.lang.document.TextRegion;
+import net.sourceforge.pmd.lang.impl.CpdOnlyLanguageModuleBase;
+import net.sourceforge.pmd.lang.impl.SimpleLanguageModuleBase;
+import net.sourceforge.pmd.reporting.RuleViolation;
+import net.sourceforge.pmd.reporting.ViolationDecorator;
+
+/**
+ * Dummy language used for testing PMD.
+ */
+public class CpdOnlyDummyLanguage extends CpdOnlyLanguageModuleBase {
+
+    public static final String NAME = "DummyCpdOnly";
+    public static final String TERSE_NAME = "dummy_cpd_only";
+
+    public CpdOnlyDummyLanguage() {
+        super(LanguageMetadata.withId(TERSE_NAME).name(NAME).extensions("dummy", "txt")
+                              .addDefaultVersion("1.7", "7"));
+    }
+
+    public static CpdOnlyDummyLanguage getInstance() {
+        return (CpdOnlyDummyLanguage) Objects.requireNonNull(LanguageRegistry.CPD.getLanguageByFullName(NAME));
+    }
+
+    @Override
+    public CpdLexer createCpdLexer(LanguagePropertyBundle bundle) {
+        return new AnyCpdLexer();
+    }
+}

pmd-core/src/test/java/net/sourceforge/pmd/lang/DummyLanguageNoCapabilities.java

@@ -0,0 +1,30 @@
+/**
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+package net.sourceforge.pmd.lang;
+
+import java.util.Objects;
+
+import net.sourceforge.pmd.cpd.AnyCpdLexer;
+import net.sourceforge.pmd.cpd.CpdLexer;
+import net.sourceforge.pmd.lang.impl.CpdOnlyLanguageModuleBase;
+
+/**
+ * Dummy language used for testing PMD.
+ */
+public class DummyLanguageNoCapabilities extends LanguageModuleBase {
+
+    public static final String NAME = "DummyNoCapabilities";
+    public static final String TERSE_NAME = "dummy_no_capabilities";
+
+    public DummyLanguageNoCapabilities() {
+        super(LanguageMetadata.withId(TERSE_NAME).name(NAME).extensions("dummyxxx", "txt")
+                              .addDefaultVersion("1.7", "7"));
+    }
+
+    public static DummyLanguageNoCapabilities getInstance() {
+        return (DummyLanguageNoCapabilities) Objects.requireNonNull(LanguageRegistry.ALL_LANGUAGES.getLanguageByFullName(NAME));
+    }
+
+}

pmd-core/src/test/resources/META-INF/services/net.sourceforge.pmd.lang.Language

@@ -1,2 +1,4 @@
 net.sourceforge.pmd.lang.DummyLanguageModule
 net.sourceforge.pmd.lang.Dummy2LanguageModule
+net.sourceforge.pmd.lang.CpdOnlyDummyLanguage
+net.sourceforge.pmd.lang.DummyLanguageNoCapabilities