Revert "Let workers finish lost races without delaying dynamic execution."

This reverts commit 6080c1e.

Author: larsrc-google

src/main/java/com/google/devtools/build/lib/worker/SingleplexWorker.java

@@ -120,12 +120,24 @@ void putRequest(WorkRequest request) throws IOException {
   @Override
   WorkResponse getResponse(int requestId) throws IOException, InterruptedException {
     recordingInputStream.startRecording(4096);
-    while (recordingInputStream.available() == 0) {
-      Thread.sleep(10);
-      if (!process.isAlive()) {
-        throw new IOException(
-            String.format(
-                "Worker process for %s died while waiting for response", workerKey.getMnemonic()));
+    // Ironically, we don't allow interrupts during dynamic execution, since we can't cancel
+    // the worker short of destroying it.
+    if (!workerKey.isSpeculative()) {
+      while (recordingInputStream.available() == 0) {
+        try {
+          Thread.sleep(10);
+        } catch (InterruptedException e) {
+          // This should only happen when not in dynamic execution, so we can safely kill the
+          // worker.
+          destroy();
+          throw e;
+        }
+        if (!process.isAlive()) {
+          throw new IOException(
+              String.format(
+                  "Worker process for %s died while waiting for response",
+                  workerKey.getMnemonic()));
+        }
       }
     }
     return workerProtocol.getResponse();

src/main/java/com/google/devtools/build/lib/worker/WorkerSpawnRunner.java

@@ -457,10 +457,6 @@ WorkResponse execInWorker(
 
         try {
           response = worker.getResponse(request.getRequestId());
-        } catch (InterruptedException e) {
-          finishWorkAsync(key, worker, request);
-          worker = null;
-          throw e;
         } catch (IOException e) {
           restoreInterrupt(e);
           // If protobuf or json reader couldn't parse the response, try to print whatever the
@@ -518,41 +514,6 @@ WorkResponse execInWorker(
     return response;
   }
 
-  /**
-   * Starts a thread to collect the response from a worker when it's no longer of interest.
-   *
-   * <p>This can happen either when we lost the race in dynamic execution or the build got
-   * interrupted. This takes ownership of the worker for purposes of returning it to the worker
-   * pool.
-   */
-  private void finishWorkAsync(WorkerKey key, Worker worker, WorkRequest request) {
-    Thread reaper =
-        new Thread(
-            () -> {
-              Worker w = worker;
-              try {
-                w.getResponse(request.getRequestId());
-              } catch (IOException | InterruptedException e1) {
-                // If this happens, we either can't trust the output of the worker, or we got
-                // interrupted while handling being interrupted. In the latter case, let's stop
-                // trying and just destroy the worker. If it's a singleplex worker, there will
-                // be a dangling response that we don't want to keep trying to read, so we destroy
-                // the worker.
-                try {
-                  workers.invalidateObject(key, w);
-                  w = null;
-                } catch (IOException | InterruptedException e2) {
-                  // The reaper thread can't do anything useful about this.
-                }
-              } finally {
-                if (w != null) {
-                  workers.returnObject(key, w);
-                }
-              }
-            });
-    reaper.start();
-  }
-
   private static void restoreInterrupt(IOException e) {
     if (e instanceof InterruptedIOException) {
       Thread.currentThread().interrupt();

src/test/java/com/google/devtools/build/lib/worker/ExampleWorker.java

@@ -35,11 +35,8 @@
 import java.util.Map;
 import java.util.Random;
 import java.util.UUID;
-import java.util.concurrent.Semaphore;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import sun.misc.Signal;
-import sun.misc.SignalHandler;
 
 /** An example implementation of a worker process that is used for integration tests. */
 public class ExampleWorker {
@@ -82,23 +79,6 @@ private static void runPersistentWorker(ExampleWorkerOptions workerOptions) thro
     PrintStream originalStdOut = System.out;
     PrintStream originalStdErr = System.err;
 
-    if (workerOptions.waitForSignal) {
-      Semaphore signalSem = new Semaphore(0);
-      Signal.handle(
-          new Signal("HUP"),
-          new SignalHandler() {
-            @Override
-            public void handle(Signal sig) {
-              signalSem.release();
-            }
-          });
-      try {
-        signalSem.acquire();
-      } catch (InterruptedException e) {
-        System.out.println("Interrupted while waiting for signal");
-        e.printStackTrace();
-      }
-    }
     ExampleWorkerProtocol workerProtocol = null;
     switch (workerOptions.workerProtocol) {
       case JSON:

src/test/java/com/google/devtools/build/lib/worker/ExampleWorkerOptions.java

@@ -135,14 +135,6 @@ public static class ExampleWorkOptions extends OptionsBase {
   )
   public boolean hardPoison;
 
-  @Option(
-      name = "wait_for_signal",
-      documentationCategory = OptionDocumentationCategory.UNCATEGORIZED,
-      effectTags = {OptionEffectTag.NO_OP},
-      defaultValue = "false",
-      help = "Don't send a response until receiving a SIGXXXX.")
-  public boolean waitForSignal;
-
   /** Enum converter for --worker_protocol. */
   public static class WorkerProtocolEnumConverter
       extends EnumConverter<ExecutionRequirements.WorkerProtocolFormat> {

src/test/java/com/google/devtools/build/lib/worker/WorkerTest.java

@@ -174,6 +174,11 @@ private void verifyGetResponseFailure(String responseString, String expectedErro
     assertThat(ex).hasMessageThat().contains(expectedError);
   }
 
+  @Test
+  public void testGetResponse_json_emptyString_throws() throws IOException {
+    verifyGetResponseFailure("", "Could not parse json work request correctly");
+  }
+
   @Test
   public void testGetResponse_badJson_throws() throws IOException {
     verifyGetResponseFailure(