[java] Fix #5293: Parse number of type parameters eagerly (#5309)

docs/pages/release_notes.md

@@ -17,6 +17,8 @@ This is a {{ site.pmd.release_type }} release.
 ### 🐛 Fixed Issues
 * ant
   * [#1860](https://github.com/pmd/pmd/issues/1860): \[ant] Reflective access warnings on java > 9 and java < 17
+* java
+  * [#5293](https://github.com/pmd/pmd/issues/5293): \[java] Deadlock when executing PMD in multiple threads
 
 ### 🚨 API Changes
 

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

@@ -84,12 +84,7 @@ final class ClassStub implements JClassSymbol, AsmStub, AnnotationOwner {
         this.resolver = resolver;
         this.names = new Names(internalName);
 
-        this.parseLock = new ParseLock() {
+        this.parseLock = new ParseLock("ClassStub:" + internalName) {
-            // note to devs: to debug the parsing logic you might have
-            // to replace the implementation of toString temporarily,
-            // otherwise an IDE could call toString just to show the item
-            // in the debugger view (which could cause parsing of the class file).
-
             @Override
             protected boolean doParse() throws IOException {
                 try (InputStream instream = loader.getInputStream()) {
@@ -315,9 +310,9 @@ final class ClassStub implements JClassSymbol, AsmStub, AnnotationOwner {
     }
 
     @Override
-    public boolean isGeneric() {
+    public int getTypeParameterCount() {
         parseLock.ensureParsed();
-        return signature.isGeneric();
+        return signature.getTypeParameterCount();
     }
 
     @Override

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

@@ -46,9 +46,9 @@ abstract class GenericSigBase<T extends JTypeParameterOwnerSymbol & AsmStub> {
     protected List<JTypeVar> typeParameters;
     private final ParseLock lock;
 
-    protected GenericSigBase(T ctx) {
+    protected GenericSigBase(T ctx, String parseLockName) {
         this.ctx = ctx;
-        this.lock = new ParseLock() {
+        this.lock = new ParseLock(parseLockName) {
             @Override
             protected boolean doParse() {
                 GenericSigBase.this.doParse();
@@ -81,7 +81,11 @@ abstract class GenericSigBase<T extends JTypeParameterOwnerSymbol & AsmStub> {
 
     protected abstract boolean postCondition();
 
-    protected abstract boolean isGeneric();
+    protected abstract int getTypeParameterCount();
+
+    protected boolean isGeneric() {
+        return getTypeParameterCount() > 0;
+    }
 
     public void setTypeParams(List<JTypeVar> tvars) {
         assert this.typeParameters == null : "Type params were already parsed for " + this;
@@ -105,6 +109,7 @@ abstract class GenericSigBase<T extends JTypeParameterOwnerSymbol & AsmStub> {
         private static final String OBJECT_BOUND = ":" + OBJECT_SIG;
 
         private final @Nullable String signature;
+        private final int typeParameterCount;
 
         private @Nullable JClassType superType;
         private List<JClassType> superItfs;
@@ -116,8 +121,9 @@ abstract class GenericSigBase<T extends JTypeParameterOwnerSymbol & AsmStub> {
                            @Nullable String signature, // null if doesn't use generics in header
                            @Nullable String superInternalName, // null if this is the Object class
                            String[] interfaces) {
-            super(ctx);
+            super(ctx, "LazyClassSignature:" + ctx.getInternalName() + "[" + signature + "]");
             this.signature = signature;
+            this.typeParameterCount = GenericTypeParameterCounter.determineTypeParameterCount(this.signature);
 
             this.rawItfs = CollectionUtil.map(interfaces, ctx.getResolver()::resolveFromInternalNameCannotFail);
             this.rawSuper = ctx.getResolver().resolveFromInternalNameCannotFail(superInternalName);
@@ -157,8 +163,9 @@ abstract class GenericSigBase<T extends JTypeParameterOwnerSymbol & AsmStub> {
         }
 
         @Override
-        protected boolean isGeneric() {
+        protected int getTypeParameterCount() {
-            return signature != null && TypeParamsParser.hasTypeParams(signature);
+            // note: no ensureParsed() needed, the type parameters are counted eagerly
+            return typeParameterCount;
         }
 
         @Override
@@ -206,6 +213,7 @@ abstract class GenericSigBase<T extends JTypeParameterOwnerSymbol & AsmStub> {
     static class LazyMethodType extends GenericSigBase<ExecutableStub> implements TypeAnnotationReceiver {
 
         private final @NonNull String signature;
+        private final int typeParameterCount;
 
         private @Nullable TypeAnnotationSet receiverAnnotations;
         private List<JTypeMirror> parameterTypes;
@@ -233,8 +241,9 @@ abstract class GenericSigBase<T extends JTypeParameterOwnerSymbol & AsmStub> {
                        @Nullable String genericSig,
                        @Nullable String[] exceptions,
                        boolean skipFirstParam) {
-            super(ctx);
+            super(ctx, "LazyMethodType:" + (genericSig != null ? genericSig : descriptor));
             this.signature = genericSig != null ? genericSig : descriptor;
+            this.typeParameterCount = GenericTypeParameterCounter.determineTypeParameterCount(genericSig);
             // generic signatures already omit the synthetic param
             this.skipFirstParam = skipFirstParam && genericSig == null;
             this.rawExceptions = exceptions;
@@ -288,8 +297,9 @@ abstract class GenericSigBase<T extends JTypeParameterOwnerSymbol & AsmStub> {
 
 
         @Override
-        protected boolean isGeneric() {
+        protected int getTypeParameterCount() {
-            return TypeParamsParser.hasTypeParams(signature);
+            // note: no ensureParsed() needed, the type parameters are counted eagerly
+            return typeParameterCount;
         }
 
         void setParameterTypes(List<JTypeMirror> params) {

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

@@ -0,0 +1,36 @@
+/*
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+package net.sourceforge.pmd.lang.java.symbols.internal.asm;
+
+import org.objectweb.asm.signature.SignatureReader;
+import org.objectweb.asm.signature.SignatureVisitor;
+
+class GenericTypeParameterCounter extends SignatureVisitor {
+    private int count;
+
+    GenericTypeParameterCounter() {
+        super(AsmSymbolResolver.ASM_API_V);
+    }
+
+    @Override
+    public void visitFormalTypeParameter(String name) {
+        count++;
+    }
+
+    public int getCount() {
+        return count;
+    }
+
+    static int determineTypeParameterCount(String signature) {
+        if (signature == null) {
+            return 0;
+        }
+
+        SignatureReader signatureReader = new SignatureReader(signature);
+        GenericTypeParameterCounter counter = new GenericTypeParameterCounter();
+        signatureReader.accept(counter);
+        return counter.getCount();
+    }
+}

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

@@ -35,7 +35,7 @@ class ModuleStub implements JModuleSymbol, AsmStub, AnnotationOwner {
         this.resolver = resolver;
         this.moduleName = moduleName;
 
-        this.parseLock = new ParseLock() {
+        this.parseLock = new ParseLock("ModuleStub:" + moduleName) {
             @Override
             protected boolean doParse() throws IOException {
                 try (InputStream instream = loader.getInputStream()) {

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

@@ -17,15 +17,30 @@ abstract class ParseLock {
     private static final Logger LOG = LoggerFactory.getLogger(ParseLock.class);
 
     private volatile ParseStatus status = ParseStatus.NOT_PARSED;
+    private final String name;
+
+    protected ParseLock(String name) {
+        this.name = name;
+    }
 
     public void ensureParsed() {
         getFinalStatus();
     }
 
+    private void logParseLockTrace(String prefix) {
+        if (LOG.isTraceEnabled()) {
+            LOG.trace("{} {}: {}", Thread.currentThread().getName(), String.format("%-15s", prefix), this);
+        }
+    }
+
     private ParseStatus getFinalStatus() {
         ParseStatus status = this.status;
         if (!status.isFinished) {
+            logParseLockTrace("waiting on");
+
             synchronized (this) {
+                logParseLockTrace("locked");
+
                 status = this.status;
                 if (status == ParseStatus.NOT_PARSED) {
                     this.status = ParseStatus.BEING_PARSED;
@@ -54,6 +69,7 @@ abstract class ParseLock {
                     throw new IllegalStateException("Thread is reentering the parse lock");
                 }
             }
+            logParseLockTrace("released");
         }
         return status;
     }
@@ -85,7 +101,7 @@ abstract class ParseLock {
 
     @Override
     public String toString() {
-        return "ParseLock{status=" + status + '}';
+        return "ParseLock{name=" + name + ",status=" + status + '}';
     }
 
     private enum ParseStatus {

pmd-java/src/test/java/net/sourceforge/pmd/lang/java/symbols/DeadlockTest.java

@@ -0,0 +1,157 @@
+/*
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+package net.sourceforge.pmd.lang.java.symbols;
+
+import static org.junit.jupiter.api.Assertions.assertAll;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+
+import net.sourceforge.pmd.lang.java.JavaParsingHelper;
+import net.sourceforge.pmd.lang.java.ast.ASTClassType;
+import net.sourceforge.pmd.lang.java.ast.ASTCompilationUnit;
+
+/**
+ * Tests to help analyze  [java] Deadlock when executing PMD in multiple threads #5293.
+ *
+ * @see <a href="https://github.com/pmd/pmd/issues/5293">[java] Deadlock when executing PMD in multiple threads #5293</a>
+ */
+class DeadlockTest {
+
+    abstract static class Outer<T> implements GenericInterface<Outer<T>, GenericClass<T>> {
+        // must be a nested class, that is reusing the type param T of the outer class
+        abstract static class Inner<T> {
+            Inner(Outer<T> grid) { }
+        }
+    }
+
+    static class GenericBaseClass<T> { }
+
+    interface GenericInterface<T, S> { }
+
+    abstract static class GenericClass<T> extends GenericBaseClass<Outer.Inner<T>> { }
+
+    @Test
+    @Timeout(2)
+    void parseWithoutDeadlock() throws InterruptedException {
+        /*
+         Deadlock:
+         t1 -> locks parse for Outer.Inner and waits for parse lock for Outer
+          ├─ t1 waiting on        : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer$Inner[<T:Ljava/lang/Object;>Ljava/lang/Object;],status=NOT_PARSED}
+          └─ t1 locked            : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer$Inner[<T:Ljava/lang/Object;>Ljava/lang/Object;],status=NOT_PARSED}
+             └─ t1 waiting on     : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer[<T:Ljava/lang/Object;>Ljava/lang/Object;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericInterface<Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer<TT;>;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericClass<TT;>;>;],status=BEING_PARSED}
+         t2 -> locks parse for Outer, locks parse for GenericInterface and then waits for parse lock for Outer.Inner
+          ├─ t2 waiting on        : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer[<T:Ljava/lang/Object;>Ljava/lang/Object;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericInterface<Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer<TT;>;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericClass<TT;>;>;],status=NOT_PARSED}
+          └─ t2 locked            : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer[<T:Ljava/lang/Object;>Ljava/lang/Object;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericInterface<Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer<TT;>;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericClass<TT;>;>;],status=NOT_PARSED}
+             ├─ t2 waiting on     : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest[null],status=NOT_PARSED}
+             ├─ t2 locked         : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest[null],status=NOT_PARSED}
+             ├─ t2 released       : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest[null],status=FULL}
+             ├─ t2 waiting on     : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer[<T:Ljava/lang/Object;>Ljava/lang/Object;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericInterface<Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer<TT;>;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericClass<TT;>;>;],status=BEING_PARSED}
+             ├─ t2 locked         : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer[<T:Ljava/lang/Object;>Ljava/lang/Object;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericInterface<Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer<TT;>;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericClass<TT;>;>;],status=BEING_PARSED}
+             ├─ t2 released       : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer[<T:Ljava/lang/Object;>Ljava/lang/Object;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericInterface<Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer<TT;>;Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericClass<TT;>;>;],status=BEING_PARSED}
+             └─ t2 waiting on     : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericClass[<T:Ljava/lang/Object;>Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericBaseClass<Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer$Inner<TT;>;>;],status=NOT_PARSED}
+               ├─ t2 locked       : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericClass[<T:Ljava/lang/Object;>Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$GenericBaseClass<Lnet/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer$Inner<TT;>;>;],status=NOT_PARSED}
+               └─ t2 waiting on   : ParseLock{name=LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer$Inner[<T:Ljava/lang/Object;>Ljava/lang/Object;],status=NOT_PARSED}
+
+
+        In order to reproduce the deadlock reliably, add the following piece into ParseLock, just at the beginning
+        of the synchronized block (line 42):
+
+        // t1 needs to wait after having the lock, so that t2 can go on and wait on the same lock
+        if (Thread.currentThread().getName().equals("t1") && this.toString().contains("LazyClassSignature:net/sourceforge/pmd/lang/java/symbols/DeadlockTest$Outer$Inner[<T:L")) {
+            try {
+                Thread.sleep(500);
+            } catch (InterruptedException ignored) {
+            }
+        }
+
+        And then, introduce a bug again. One way to make the test fail is:
+        Comment out the method "public int getTypeParameterCount()", so that it is inherited again.
+        Add the following method:
+            @Override
+            public boolean isGeneric() {
+                parseLock.ensureParsed();
+                return signature.isGeneric();
+            }
+         */
+
+        List<Throwable> exceptions = new ArrayList<>();
+        Thread.UncaughtExceptionHandler exceptionHandler = (t, e) -> {
+            exceptions.add(e);
+            e.printStackTrace();
+        };
+
+        Thread t1 = new Thread(() -> {
+            ASTCompilationUnit class1 = JavaParsingHelper.DEFAULT.parse(
+                    "package net.sourceforge.pmd.lang.java.symbols;\n"
+                            + "import net.sourceforge.pmd.lang.java.symbols.DeadlockTest.Outer;\n"
+                            + "  class Class1 {\n"
+                            + "    public static <X> Outer.Inner<X> newInner(Outer<X> grid) {\n"
+                            + "      return null;\n"
+                            + "    }\n"
+                            + "  }\n"
+            );
+            assertNotNull(class1);
+
+            // Outer.Inner<X> = return type of method "newInner"
+            List<ASTClassType> classTypes = class1.descendants(ASTClassType.class).toList();
+            ASTClassType outerInner = classTypes.get(0);
+            assertGenericClassType(outerInner, "Inner", "X", "T");
+
+            // Outer = qualifier of Outer.Inner<X>
+            ASTClassType outer = classTypes.get(1);
+            assertEquals("Outer", outer.getSimpleName());
+            assertNull(outer.getTypeArguments());
+
+            // Outer<X> = formal parameter type of method newInner
+            ASTClassType outerFormalParam = classTypes.get(3);
+            assertGenericClassType(outerFormalParam, "Outer", "X", "T");
+        }, "t1");
+        t1.setUncaughtExceptionHandler(exceptionHandler);
+
+        Thread t2 = new Thread(() -> {
+            ASTCompilationUnit class2 = JavaParsingHelper.DEFAULT.parse(
+                    "package net.sourceforge.pmd.lang.java.symbols;\n"
+                            + "import net.sourceforge.pmd.lang.java.symbols.DeadlockTest.Outer;\n"
+                            + "  class Class2<M> {\n"
+                            + "    protected Outer<M> theOuter;\n"
+                            + "  }\n"
+            );
+            assertNotNull(class2);
+
+            // Outer<M> = type of field "theOuter"
+            ASTClassType firstClassType = class2.descendants(ASTClassType.class).first();
+            assertNotNull(firstClassType);
+            assertGenericClassType(firstClassType, "Outer", "M", "T");
+        }, "t2");
+        t2.setUncaughtExceptionHandler(exceptionHandler);
+
+        t1.start();
+        t2.start();
+
+        t1.join();
+        t2.join();
+
+        assertAll(exceptions.stream()
+                        .map(e -> () -> {
+                            throw e;
+                        }));
+    }
+
+    private static void assertGenericClassType(ASTClassType classType, String simpleName, String actualTypeParamName, String originalTypeParamName) {
+        assertEquals(simpleName, classType.getSimpleName());
+        assertEquals(1, classType.getTypeArguments().size());
+        assertEquals(actualTypeParamName, ((ASTClassType) classType.getTypeArguments().get(0)).getSimpleName());
+        JTypeParameterOwnerSymbol symbol = (JTypeParameterOwnerSymbol) classType.getTypeMirror().getSymbol();
+        assertEquals(1, symbol.getTypeParameterCount());
+        assertEquals(originalTypeParamName, symbol.getTypeParameters().get(0).getName());
+    }
+}

pmd-java/src/test/resources/simplelogger.properties

@@ -0,0 +1,5 @@
+#
+# BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+#
+
+#org.slf4j.simpleLogger.log.net.sourceforge.pmd.lang.java.symbols.internal.asm.ParseLock=trace