Add classpath abstraction - meant to ease testing

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/symbols/internal/asm/AsmSymbolResolver.java

@@ -27,7 +27,7 @@ public class AsmSymbolResolver implements SymbolResolver {
     static final int ASM_API_V = Opcodes.ASM9;
 
     private final TypeSystem ts;
-    private final ClassLoader classLoader;
+    private final Classpath classLoader;
     private final SignatureParser typeLoader;
 
     private final ConcurrentHashMap<String, SoftClassReference> knownStubs = new ConcurrentHashMap<>();
@@ -38,7 +38,7 @@ public class AsmSymbolResolver implements SymbolResolver {
      */
     private final SoftClassReference failed;
 
-    public AsmSymbolResolver(TypeSystem ts, ClassLoader classLoader) {
+    public AsmSymbolResolver(TypeSystem ts, Classpath classLoader) {
         this.ts = ts;
         this.classLoader = classLoader;
         this.typeLoader = new SignatureParser(this);
@@ -104,7 +104,7 @@ public class AsmSymbolResolver implements SymbolResolver {
 
     @Nullable
     URL getUrlOfInternalName(String internalName) {
-        return classLoader.getResource(internalName + ".class");
+        return classLoader.getURLForResource(internalName + ".class");
     }
 
     /*

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/symbols/internal/asm/Classpath.java

@@ -0,0 +1,29 @@
+/*
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+package net.sourceforge.pmd.lang.java.symbols.internal.asm;
+
+import java.net.URL;
+
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+/**
+ * Classpath abstraction.
+ */
+public interface Classpath {
+
+    /**
+     * Returns a URL to load the given resource if it exists in this classpath.
+     * Otherwise returns null.
+     */
+    @Nullable URL getURLForResource(String resourcePath);
+
+    /**
+     * Returns a classpath instance that uses {@link ClassLoader#getResource(String)}
+     * to find resources.
+     */
+    static Classpath forClassLoader(ClassLoader classLoader) {
+        return classLoader::getResource;
+    }
+}

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/types/TypeSystem.java

@@ -33,6 +33,7 @@ import net.sourceforge.pmd.lang.java.symbols.JTypeParameterSymbol;
 import net.sourceforge.pmd.lang.java.symbols.SymbolResolver;
 import net.sourceforge.pmd.lang.java.symbols.internal.UnresolvedClassStore;
 import net.sourceforge.pmd.lang.java.symbols.internal.asm.AsmSymbolResolver;
+import net.sourceforge.pmd.lang.java.symbols.internal.asm.Classpath;
 import net.sourceforge.pmd.lang.java.types.BasePrimitiveSymbol.RealPrimitiveSymbol;
 import net.sourceforge.pmd.lang.java.types.BasePrimitiveSymbol.VoidSymbol;
 import net.sourceforge.pmd.lang.java.types.JPrimitiveType.PrimitiveTypeKind;
@@ -53,7 +54,7 @@ import net.sourceforge.pmd.util.CollectionUtil;
  * <p>The lifetime of a type system is the analysis: it is shared by
  * all compilation units.
  * TODO this is hacked together by comparing the ClassLoader, but this
- *  should be in the language instance
+ * should be in the language instance
  *
  * <p>Nodes have a reference to the type system they were created for:
  * {@link JavaNode#getTypeSystem()}.
@@ -179,8 +180,20 @@ public final class TypeSystem {
      *                                to populate the fields of the new type
      *                                system
      */
-    public TypeSystem(ClassLoader bootstrapResourceLoader) {
-        this(ts -> new AsmSymbolResolver(ts, bootstrapResourceLoader));
+    public static TypeSystem usingClassLoaderClasspath(ClassLoader bootstrapResourceLoader) {
+        return usingClasspath(Classpath.forClassLoader(bootstrapResourceLoader));
+    }
+
+    /**
+     * Builds a new type system. Its public fields will be initialized
+     * with fresh types, unrelated to other types.
+     *
+     * @param bootstrapResourceLoader Classpath used to resolve class files
+     *                                to populate the fields of the new type
+     *                                system
+     */
+    public static TypeSystem usingClasspath(Classpath bootstrapResourceLoader) {
+        return new TypeSystem(ts -> new AsmSymbolResolver(ts, bootstrapResourceLoader));
     }
 
     /**
@@ -724,6 +737,7 @@ public final class TypeSystem {
     }
 
     private static final class NullType implements JTypeMirror {
+
         private final TypeSystem ts;
 
         NullType(TypeSystem ts) {

pmd-java/src/test/java/net/sourceforge/pmd/lang/java/JavaParsingHelper.java

@@ -37,7 +37,7 @@ public class JavaParsingHelper extends BaseParsingHelper<JavaParsingHelper, ASTC
      * default options of JavaParsingHelper. This allows constants like
      * the null type to be compared.
      */
-    public static final TypeSystem TEST_TYPE_SYSTEM = new TypeSystem(JavaParsingHelper.class.getClassLoader());
+    public static final TypeSystem TEST_TYPE_SYSTEM = TypeSystem.usingClassLoaderClasspath(JavaParsingHelper.class.getClassLoader());
 
     /** This just runs the parser and no processing stages. */
     public static final JavaParsingHelper JUST_PARSE = new JavaParsingHelper(Params.getDefaultNoProcess(), SemanticErrorReporter.noop(), TEST_TYPE_SYSTEM, TypeInferenceLogger.noop());

pmd-java/src/test/resources/javasymbols.brokenclasses/BrokenGeneric.java

@@ -0,0 +1,19 @@
+
+package my.pack;
+
+
+/*
+    For this test we compile this file manually, save the classes in the
+    resource tree, but purposefully exclude SuperItf.class to mimic an
+    incomplete classpath.
+ */
+
+
+class SuperKlass<A, B> { }
+interface SuperItf<A, B> { }
+
+
+public class BrokenGeneric<C, D> extends SuperKlass<C, C> implements SuperItf<D, D> {
+
+
+}