[GR-45490] Fix IO#wait specs transient failure

PullRequest: truffleruby/4182

Author: andrykonchin

CHANGELOG.md

@@ -6,6 +6,7 @@ Bug fixes:
 
 * Add missing thread-safe objects write barriers for `TruffleRuby::ConcurrentMap` (#3179, @eregon).
 * Fix repeated calling of methods `Dir#{each,each_child,children}` (#3464, @andrykonchin).
+* Fix `IO#{wait,wait_readable,wait_writable}` methods and switch the current thread into a sleep state (@andrykonchin).
 
 Compatibility:
 * Move `IO#wait_readable`, `IO#wait_writable`, `IO#wait_priority` and `IO#wait` into core library (@andrykonchin).

spec/ruby/library/io-wait/wait_spec.rb

@@ -48,25 +48,18 @@
     end
 
     it "waits for the READABLE event to be ready" do
-      queue = Queue.new
-      thread = Thread.new { queue.pop; sleep 1; @w.write('data to read') };
+      @r.wait(IO::READABLE, 0).should == nil
 
-      queue.push('signal');
-      @r.wait(IO::READABLE, 2).should_not == nil
-
-      thread.join
+      @w.write('data to read')
+      @r.wait(IO::READABLE, 0).should_not == nil
     end
 
     it "waits for the WRITABLE event to be ready" do
       written_bytes = IOWaitSpec.exhaust_write_buffer(@w)
+      @w.wait(IO::WRITABLE, 0).should == nil
 
-      queue = Queue.new
-      thread = Thread.new { queue.pop; sleep 1; @r.read(written_bytes) };
-
-      queue.push('signal');
-      @w.wait(IO::WRITABLE, 2).should_not == nil
-
-      thread.join
+      @r.read(written_bytes)
+      @w.wait(IO::WRITABLE, 0).should_not == nil
     end
 
     it "returns nil when the READABLE event is not ready during the timeout" do
@@ -89,6 +82,24 @@
         -> { @w.wait(-1, 0) }.should raise_error(ArgumentError, "Events must be positive integer!")
       end
     end
+
+    it "changes thread status to 'sleep' when waits for READABLE event" do
+      t = Thread.new { @r.wait(IO::READABLE, 10) }
+      sleep 1
+      t.status.should == 'sleep'
+      t.kill
+      t.join # Thread#kill doesn't wait for the thread to end
+    end
+
+    it "changes thread status to 'sleep' when waits for WRITABLE event" do
+      written_bytes = IOWaitSpec.exhaust_write_buffer(@w)
+
+      t = Thread.new { @w.wait(IO::WRITABLE, 10) }
+      sleep 1
+      t.status.should == 'sleep'
+      t.kill
+      t.join # Thread#kill doesn't wait for the thread to end
+    end
   end
 
   context "[timeout, mode] passed" do

spec/tags/library/io-wait/wait_tags.txt

@@ -585,6 +585,33 @@ Object status(RubyThread self) {
 
     }
 
+    @Primitive(name = "thread_set_status")
+    public abstract static class ThreadSetStatusPrimitiveNode extends PrimitiveArrayArgumentsNode {
+
+        @TruffleBoundary
+        @Specialization
+        Object threadSetStatus(RubyThread thread, RubySymbol status) {
+            ThreadStatus current = thread.status;
+            String newName = status.getString();
+
+            if (newName.equals("run")) {
+                thread.status = ThreadStatus.RUN;
+            } else if (newName.equals("sleep")) {
+                thread.status = ThreadStatus.SLEEP;
+            } else if (newName.equals("aborting")) {
+                thread.status = ThreadStatus.ABORTING;
+            } else if (newName.equals("dead")) {
+                thread.status = ThreadStatus.DEAD;
+            } else {
+                throw new RaiseException(getContext(),
+                        coreExceptions().argumentError("Unknown thread status: " + newName, this));
+            }
+
+            String currentName = StringUtils.toLowerCase(current.name());
+            return getLanguage().getSymbol(currentName);
+        }
+    }
+
     @CoreMethod(names = "native_thread_id")
     public abstract static class NativeThreadIdNode extends CoreMethodArrayArgumentsNode {
 

src/main/java/org/truffleruby/core/thread/ThreadNodes.java

@@ -259,7 +259,13 @@ def self.poll(io, event_mask, timeout)
       end
 
       begin
+        # Change thread status manually.
+        # Don't mark Truffle::POSIX.truffleposix_poll_single_fd as blocking because
+        # then it would automatically retry on EINTR without considering/adjusting the timeout.
+        status = Primitive.thread_set_status(Thread.current, :sleep)
         returned_events = Truffle::POSIX.truffleposix_poll_single_fd(Primitive.io_fd(io), event_mask, remaining_timeout)
+        Primitive.thread_set_status(Thread.current, status)
+
         result =
           if returned_events < 0
             errno = Errno.errno