[java] Cyclomatic complexity is misreported (lack of clearing metrics cache)

Fixes #1984

docs/pages/release_notes.md

@@ -55,6 +55,7 @@ Any feedback about it, especially about your use cases, is highly appreciated.
 ### Fixed Issues
 
 *   core
+    *   [#1984](https://github.com/pmd/pmd/issues/1984): \[java] Cyclomatic complexity is misreported (lack of clearing metrics cache)
     *   [#2006](https://github.com/pmd/pmd/issues/2006): \[core] PMD should warn about multiple instances of the same rule in a ruleset
     *   [#2161](https://github.com/pmd/pmd/issues/2161): \[core] ResourceLoader is deprecated and marked as internal but is exposed
     *   [#2170](https://github.com/pmd/pmd/issues/2170): \[core] DocumentFile doesn't preserve newlines

pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/ApexHandler.java

@@ -17,6 +17,7 @@ import net.sourceforge.pmd.lang.apex.ast.ASTMethod;
 import net.sourceforge.pmd.lang.apex.ast.ASTUserClassOrInterface;
 import net.sourceforge.pmd.lang.apex.ast.ApexNode;
 import net.sourceforge.pmd.lang.apex.ast.DumpFacade;
+import net.sourceforge.pmd.lang.apex.metrics.ApexMetrics;
 import net.sourceforge.pmd.lang.apex.metrics.ApexMetricsComputer;
 import net.sourceforge.pmd.lang.apex.metrics.api.ApexClassMetricKey;
 import net.sourceforge.pmd.lang.apex.metrics.api.ApexOperationMetricKey;
@@ -80,6 +81,10 @@ public class ApexHandler extends AbstractLanguageVersionHandler {
             super((Class<ASTUserClassOrInterface<?>>) (Object) ASTUserClassOrInterface.class, ASTMethod.class, ApexMetricsComputer.getInstance());
         }
 
+        @Override
+        public void initialize() {
+            ApexMetrics.reset();
+        }
 
         @Override
         public List<ApexClassMetricKey> getAvailableTypeMetrics() {

pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/metrics/ApexMetrics.java

@@ -37,8 +37,11 @@ public final class ApexMetrics {
     }
 
 
-    /** Resets the entire data structure. Used for tests. */
-    static void reset() {
+    /**
+     * Resets the entire data structure.
+     * This needs to be done in case PMD is executed multiple times within one JVM run.
+     */
+    public static void reset() {
         FACADE.reset();
     }
 

pmd-core/src/main/java/net/sourceforge/pmd/lang/metrics/LanguageMetricsProvider.java

@@ -31,6 +31,12 @@ import net.sourceforge.pmd.lang.ast.QualifiableNode;
 @Experimental
 public interface LanguageMetricsProvider<T extends QualifiableNode, O extends QualifiableNode> {
 
+    /**
+     * Provides a hook to do any initializing before the first file is processed by PMD.
+     * This can be used by the metrics implementations to reset the cache.
+     */
+    void initialize();
+
     /**
      * Returns a list of all supported type metric keys
      * for the language.

pmd-core/src/main/java/net/sourceforge/pmd/processor/AbstractPMDProcessor.java

@@ -24,6 +24,9 @@ import net.sourceforge.pmd.SourceCodeProcessor;
 import net.sourceforge.pmd.benchmark.TimeTracker;
 import net.sourceforge.pmd.benchmark.TimedOperation;
 import net.sourceforge.pmd.benchmark.TimedOperationCategory;
+import net.sourceforge.pmd.lang.Language;
+import net.sourceforge.pmd.lang.LanguageRegistry;
+import net.sourceforge.pmd.lang.metrics.LanguageMetricsProvider;
 import net.sourceforge.pmd.renderers.Renderer;
 import net.sourceforge.pmd.util.datasource.DataSource;
 
@@ -114,6 +117,8 @@ public abstract class AbstractPMDProcessor {
         configuration.getAnalysisCache().checkValidity(rs, configuration.getClassLoader());
         final SourceCodeProcessor processor = new SourceCodeProcessor(configuration);
 
+        resetMetrics();
+
         for (final DataSource dataSource : files) {
             // this is the real, canonical and absolute filename (not shortened)
             String realFileName = dataSource.getNiceFileName(false, null);
@@ -134,6 +139,15 @@ public abstract class AbstractPMDProcessor {
         }
     }
 
+    private void resetMetrics() {
+        for (Language language : LanguageRegistry.getLanguages()) {
+            LanguageMetricsProvider<?, ?> languageMetricsProvider = language.getDefaultVersion().getLanguageVersionHandler().getLanguageMetricsProvider();
+            if (languageMetricsProvider != null) {
+                languageMetricsProvider.initialize();
+            }
+        }
+    }
+
     protected abstract void runAnalysis(PmdRunnable runnable);
 
     protected abstract void collectReports(List<Renderer> renderers);

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/AbstractJavaHandler.java

@@ -23,6 +23,7 @@ import net.sourceforge.pmd.lang.java.ast.JavaNode;
 import net.sourceforge.pmd.lang.java.ast.MethodLikeNode;
 import net.sourceforge.pmd.lang.java.dfa.DataFlowFacade;
 import net.sourceforge.pmd.lang.java.dfa.JavaDFAGraphRule;
+import net.sourceforge.pmd.lang.java.metrics.JavaMetrics;
 import net.sourceforge.pmd.lang.java.metrics.JavaMetricsComputer;
 import net.sourceforge.pmd.lang.java.metrics.api.JavaClassMetricKey;
 import net.sourceforge.pmd.lang.java.metrics.api.JavaOperationMetricKey;
@@ -178,6 +179,10 @@ public abstract class AbstractJavaHandler extends AbstractLanguageVersionHandler
             super(ASTAnyTypeDeclaration.class, MethodLikeNode.class, JavaMetricsComputer.getInstance());
         }
 
+        @Override
+        public void initialize() {
+            JavaMetrics.reset();
+        }
 
         @Override
         public List<? extends MetricKey<ASTAnyTypeDeclaration>> getAvailableTypeMetrics() {

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/JavaMetrics.java

@@ -38,8 +38,11 @@ public final class JavaMetrics {
     }
 
 
-    /** Resets the entire data structure. Used for tests. */
-    static void reset() {
+    /**
+     * Resets the entire data structure.
+     * This needs to be done in case PMD is executed multiple times within one JVM run.
+     */
+    public static void reset() {
         FACADE.reset();
     }