#1276, #1278, #1279, #1280 False positive in UnusedPrivateMethod

Make the auxclasspath option optional. Falls back to the old behavior,
which prevents many false positives.
But it introduces the false negative case #1226, if no auxclasspath is set.

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/symboltable/ClassScope.java

@@ -144,7 +144,8 @@ public class ClassScope extends AbstractJavaScope {
 
                     if (!mnd.isVarargs()
                             && occurrence.getArgumentCount() == mnd.getParameterCount()
-                            && parameterTypes.equals(argumentTypes)) {
+                            && (!getEnclosingScope(SourceFileScope.class).hasAuxclasspath()
+                                    || parameterTypes.equals(argumentTypes))) {
                         return mnd;
                     } else if (mnd.isVarargs()) {
                         int varArgIndex = parameterTypes.size() - 1;
@@ -153,8 +154,14 @@ public class ClassScope extends AbstractJavaScope {
                         // first parameter is varArg, calling method might have 0 or more arguments
                         // or the calling method has enough arguments to fill in the parameters before the vararg
                         if ((varArgIndex == 0 || argumentTypes.size() >= varArgIndex)
-                            && parameterTypes.subList(0, varArgIndex).equals(argumentTypes.subList(0, varArgIndex))) {
+                            && (!getEnclosingScope(SourceFileScope.class).hasAuxclasspath()
+                                    || parameterTypes.subList(0, varArgIndex).equals(argumentTypes.subList(0, varArgIndex)))) {
                             boolean sameType = true;
+
+                            if (!getEnclosingScope(SourceFileScope.class).hasAuxclasspath()) {
+                                return mnd;
+                            }
+
                             for (int i = varArgIndex; i < argumentTypes.size(); i++) {
                                 if (!varArgType.equals(argumentTypes.get(i))) {
                                     sameType = false;

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/symboltable/SourceFileScope.java

@@ -45,6 +45,17 @@ public class SourceFileScope extends AbstractJavaScope {
         }
     }
 
+    /**
+     * Whether an auxclasspath has been configured or not.
+     * This can be used to enable/disable more detailed symbol table analysis and type resolution
+     * can be used - or to fall back to more simple implementation.
+     * @return <code>true</code> if the auxclasspath is configured and types can be resolved reliably.
+     * @see #resolveType(String)
+     */
+    public boolean hasAuxclasspath() {
+        return types.hasAuxclasspath();
+    }
+
     /**
      * Tries to resolve a class by name.
      * @param name the name of the class

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/symboltable/TypeSet.java

@@ -11,6 +11,7 @@ import java.util.Map;
 import java.util.Set;
 
 import net.sourceforge.pmd.lang.java.typeresolution.PMDASMClassLoader;
+import net.sourceforge.pmd.util.ClasspathClassLoader;
 
 /**
  * Keeps track of the types encountered in a ASTCompilationUnit
@@ -18,6 +19,7 @@ import net.sourceforge.pmd.lang.java.typeresolution.PMDASMClassLoader;
 public class TypeSet {
 
     private final PMDASMClassLoader pmdClassLoader;
+    private boolean hasAuxclasspath;
 
     /**
      * The {@link TypeSet} provides type resolution for the symbol facade.
@@ -35,9 +37,18 @@ public class TypeSet {
         if (cl == null) {
             cl = TypeSet.class.getClassLoader();
         }
+        hasAuxclasspath = cl instanceof ClasspathClassLoader;
         pmdClassLoader = PMDASMClassLoader.getInstance(cl);
     }
 
+    /**
+     * Whether the classloader is using the auxclasspath or not.
+     * @return <code>true</code> if the classloader is using the auxclasspath feature
+     */
+    public boolean hasAuxclasspath() {
+        return hasAuxclasspath;
+    }
+
     /**
      * A resolver that can resolve a class by name. The name can be a simple name or a fully qualified name.
      */

pmd-test/src/main/java/net/sourceforge/pmd/testframework/RuleTst.java

@@ -200,17 +200,22 @@ public abstract class RuleTst {
     /**
      * Run the rule on the given code and put the violations in the report.
      */
-    public void runTestFromString(String code, Rule rule, Report report, LanguageVersion languageVersion) throws PMDException {
-        PMD p = new PMD();
-        p.getConfiguration().setDefaultLanguageVersion(languageVersion);
-        RuleContext ctx = new RuleContext();
-        ctx.setReport(report);
-        ctx.setSourceCodeFilename("n/a");
-        ctx.setLanguageVersion(languageVersion);
-        ctx.setIgnoreExceptions(false);
-        RuleSet rules = new RuleSet();
-        rules.addRule(rule);
-        p.getSourceCodeProcessor().processSourceCode(new StringReader(code), new RuleSets(rules), ctx);
+    public void runTestFromString(String code, Rule rule, Report report, LanguageVersion languageVersion) {
+        try {
+            PMD p = new PMD();
+            p.getConfiguration().setDefaultLanguageVersion(languageVersion);
+            p.getConfiguration().prependClasspath("."); // configure the "auxclasspath" option for unit testing
+            RuleContext ctx = new RuleContext();
+            ctx.setReport(report);
+            ctx.setSourceCodeFilename("n/a");
+            ctx.setLanguageVersion(languageVersion);
+            ctx.setIgnoreExceptions(false);
+            RuleSet rules = new RuleSet();
+            rules.addRule(rule);
+            p.getSourceCodeProcessor().processSourceCode(new StringReader(code), new RuleSets(rules), ctx);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
     }
 
     /**