pi-lens/rules/tree-sitter-queries/java/no-wait-notify-on-thread.yml

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# No Wait/Notify on Thread
# Detects wait(), notify(), notifyAll() called on Thread instances
id: no-wait-notify-on-thread
name: Wait/Notify Should Not Be Called on Thread Instances
severity: error
category: reliability
defect_class: correctness
inline_tier: blocking
language: java

message: "{{METHOD}}() should not be called on Thread instances"

description: |
  Calling wait(), notify(), or notifyAll() on Thread objects can
  conflict with the Thread's internal join mechanism, causing 
  unexpected behavior. Use them on a separate lock object.

  ✅ FIX: Use a dedicated lock object

  ```java
  private final Object lock = new Object();

  synchronized (lock) {
      lock.wait();  // GOOD - separate lock
  }
  ```

query: |
  (method_invocation
    object: (identifier) @OBJ
    name: (identifier) @METHOD
    (#match? @METHOD "^(wait|notify|notifyAll)$"))

metavars:
  - METHOD
  - OBJ

post_filter: called_on_thread_instance

tags:
  - reliability
  - java
  - multi-threading
  - bugs

examples:
  bad: |
    Thread thread = new Thread(runnable);
    thread.wait();  // BAD - on Thread instance
    thread.notify();  // BAD

  good: |
    Object lock = new Object();
    synchronized (lock) {
        lock.wait();  // GOOD - on separate lock
    }

has_fix: false