Play Deadlock Empire in Fray!

[aoli-al]

No description provided.

[Copilot]

PR Overview

This PR introduces several translated test cases under the "Deadlock Empire" theme that simulate common concurrency pitfalls. Key changes include the addition of new concurrency test classes (e.g. CountdownEvent, CountdownEventRevisited, etc.), the use of various synchronization mechanisms (CountDownLatch, CyclicBarrier, ReentrantLock, Semaphore, condition variables), and minor documentation enhancements in the CHANGELOG.

Reviewed Changes

File	Description
example/src/test/java/org/pastalab/fray/example/deadlockempire/CountdownEvent.java	Adds a test demonstrating potential deadlock with CountDownLatch.
example/src/test/java/org/pastalab/fray/example/deadlockempire/CountdownEventRevisited.java	Adds a test to trigger an exception by over-signaling a CountDownLatch.
example/src/test/java/org/pastalab/fray/example/deadlockempire/ConfusedCounter.java	Adds a test to showcase non-atomic operations in a multithreaded context.
example/src/test/java/org/pastalab/fray/example/deadlockempire/Barrier.java	Adds a test using a misconfigured CyclicBarrier with multiple threads.
example/src/test/java/org/pastalab/fray/example/deadlockempire/Deadlock.java	Adds a classic deadlock demonstration using ReentrantLock.
example/src/test/java/org/pastalab/fray/example/deadlockempire/BooleanFlags.java	Adds a test demonstrating weak synchronization using a boolean flag.
example/src/main/java/org/pastalab/fray/example/Main.java	Introduces a simple main method for application startup.
example/src/test/java/org/pastalab/fray/example/deadlockempire/BossFight.java	Adds a complex test involving semaphores and condition variables.
example/src/test/java/org/pastalab/fray/example/deadlockempire/ConditionVariables.java	Adds a test demonstrating thread coordination with wait/notify.
example/src/test/java/org/pastalab/fray/example/deadlockempire/DeadlockEmpireTestBase.java	Provides common helper methods for the test cases.
CHANGELOG.md	Updates the changelog to reflect the new tests and debugging features.

Copilot reviewed 49 out of 49 changed files in this pull request and generated 3 comments.

[Copilot]

Instead of using an 'if' statement before calling wait(), consider using a 'while' loop to handle spurious wakeups in the consumer thread.

Suggested change

	if (queue.isEmpty()) {
	while (queue.isEmpty()) {

[Copilot]

Replace the 'if' condition with a 'while' loop to guard against spurious wakeups in the consumer thread.

Suggested change

	if (queue.isEmpty()) {
	while (queue.isEmpty()) {

[Copilot]

Acquiring the semaphore immediately after a successful tryAcquire() may lead to a deadlock if the semaphore’s permits are mismatched; consider reviewing the semaphore usage to ensure that permits are acquired and released symmetrically.

Suggested change

	try {
	fortress.acquire(); // Wait for a permit
	synchronized (sanctum) {
	try {
	sanctum.wait(); // Wait to be notified
	} catch (InterruptedException e) {
	Thread.currentThread().interrupt();
	}
	criticalSection();
	}
	} catch (InterruptedException e) {
	Thread.currentThread().interrupt();
	synchronized (sanctum) {
	try {
	sanctum.wait(); // Wait to be notified
	} catch (InterruptedException e) {
	Thread.currentThread().interrupt();
	}
	criticalSection();