resolves #215 fix watchdog race condition leading to ThreadError(<killed thread>) on JRuby (#216)

Author: slonopotamus

CHANGELOG.adoc

@@ -5,6 +5,10 @@
 This document provides a high-level view of the changes to the {project-name} by release.
 For a detailed view of what has changed, refer to the {uri-repo}/commits/master[commit history] on GitHub.
 
+== Unreleased
+
+* fix watchdog race condition leading to `ThreadError(<killed thread>)` on JRuby ({uri-repo}/pull/215[#215])
+
 == 2.0.0.rc2 (2021-01-07) - @slonopotamus
 
 * Fix release workflow

lib/pygments/popen.rb

@@ -227,15 +227,17 @@ def highlight(code, opts = {})
     def with_watchdog(timeout_time, error_message)
       state_mutex = Mutex.new
       state = :alive
+      wd_cleanup = ConditionVariable.new
 
       watchdog = timeout_time > 0 ? Thread.new do
         state_mutex.synchronize do
-          state_mutex.sleep(timeout_time) if state != :finished
+          wd_cleanup.wait(state_mutex, timeout_time) if state != :finished
           if state != :finished
             @log.error error_message
             stop error_message
             state = :timeout
           end
+
         end
       end : nil
       begin
@@ -244,7 +246,8 @@ def with_watchdog(timeout_time, error_message)
         if watchdog
           state_mutex.synchronize do
             state = :finished if state == :alive
-            watchdog.wakeup if watchdog.alive?
+            # wake up watchdog thread
+            wd_cleanup.signal
           end
           watchdog.join
         end