PY-36882 Fix debugger not working properly with joblib.Parallel when using loky backend

GitOrigin-RevId: 392e04e2e10ae404caf8c561a7c951e7eaea3c9c

python/helpers/pydev/_pydevd_bundle/pydevd_comm.py

@@ -291,6 +291,8 @@ class ReaderThread(PyDBDaemonThread):
             while not self.killReceived:
                 try:
                     r = self.sock.recv(1024)
+                except OSError:
+                    return
                 except:
                     if not self.killReceived:
                         traceback.print_exc()

python/setup-test-environment/build.gradle

@@ -178,8 +178,8 @@ envs {
 
   createPython("python3.11",
                python311version,
-               ["black == 23.1.0"],
-               "python3.11\nblack",
+               ["black == 23.1.0", "joblib"],
+               "python3.11\nblack\njoblib",
                true)
 
   createPython("python3.12",

python/testData/debug/test_joblib.py

@@ -0,0 +1,8 @@
+from joblib import Parallel, delayed
+
+
+def f(i):
+    print(i)
+    return i*i
+
+Parallel(n_jobs=2, backend='loky')(delayed(f)(i) for i in range(3))

python/testSrc/com/jetbrains/env/debug/PythonDebuggerMultiprocessingTest.java

@@ -340,4 +340,32 @@ public class PythonDebuggerMultiprocessingTest extends PyEnvTestCase {
       }
     });
   }
+
+  @Test
+  @TestFor(issues = "PY-36882")
+  public void testNoErrorMessagesWithJoblib() {
+    runPythonTest(new PyDebuggerMultiprocessTask("/debug", "test_joblib.py") {
+      @Override
+      public void before() {
+        toggleBreakpoint(4);
+      }
+
+      @Override
+      public void testing() throws Exception {
+        waitForPause();
+        resume();
+        waitForPause();
+        resume();
+        waitForPause();
+        resume();
+        waitForTerminate();
+        assertFalse(output().contains("Traceback"));
+      }
+
+      @Override
+      public @NotNull Set<String> getTags() {
+        return Collections.singleton("joblib");
+      }
+    });
+  }
 }