From fbf2597ebbed36e57cf4cfbfd0987c842486a12b Mon Sep 17 00:00:00 2001
From: HwangRock <peter9244@catholic.ac.kr>
Date: Sat, 11 Jul 2026 16:37:21 +0900
Subject: [PATCH] [ZEPPELIN-6481] Restore interrupt status after
 InterruptedException in JDBC completion loading

The catch (InterruptedException e) block around awaitTermination(...) in
createOrUpdateSqlCompleter(...) logged a warning and closed the connection but
never restored the interrupt status. Catching InterruptedException clears the
thread's interrupt flag, so the interrupt was swallowed and callers on the
completion request path could no longer detect it, silently dropping
cooperative cancellation and shutdown signals.

Restore the interrupt status with Thread.currentThread().interrupt() as the
last statement of the catch block, after the connection-close attempt. Add a
unit test that pre-interrupts the calling thread, drives the completer through
the catch path, and asserts the interrupt flag is restored on return.
---
 .../apache/zeppelin/jdbc/JDBCInterpreter.java |  1 +
 .../zeppelin/jdbc/JDBCInterpreterTest.java    | 31 +++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/jdbc/src/main/java/org/apache/zeppelin/jdbc/JDBCInterpreter.java b/jdbc/src/main/java/org/apache/zeppelin/jdbc/JDBCInterpreter.java
index 196747395b2..90c34614b5f 100644
--- a/jdbc/src/main/java/org/apache/zeppelin/jdbc/JDBCInterpreter.java
+++ b/jdbc/src/main/java/org/apache/zeppelin/jdbc/JDBCInterpreter.java
@@ -328,6 +328,7 @@ public void run() {
           LOGGER.warn("Error close connection", e1);
         }
       }
+      Thread.currentThread().interrupt();
     }
     return completer;
   }
diff --git a/jdbc/src/test/java/org/apache/zeppelin/jdbc/JDBCInterpreterTest.java b/jdbc/src/test/java/org/apache/zeppelin/jdbc/JDBCInterpreterTest.java
index 2fe6dc3aab8..cc5002b22a8 100644
--- a/jdbc/src/test/java/org/apache/zeppelin/jdbc/JDBCInterpreterTest.java
+++ b/jdbc/src/test/java/org/apache/zeppelin/jdbc/JDBCInterpreterTest.java
@@ -34,6 +34,7 @@
 import org.junit.jupiter.api.Test;
 
 import java.io.IOException;
+import java.lang.reflect.Method;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.sql.Connection;
@@ -52,6 +53,7 @@
 import static java.lang.String.format;
 import static org.apache.zeppelin.jdbc.JDBCInterpreter.COMMON_MAX_LINE;
 import static org.apache.zeppelin.jdbc.JDBCInterpreter.DEFAULT_DRIVER;
+import static org.apache.zeppelin.jdbc.JDBCInterpreter.DEFAULT_KEY;
 import static org.apache.zeppelin.jdbc.JDBCInterpreter.DEFAULT_PASSWORD;
 import static org.apache.zeppelin.jdbc.JDBCInterpreter.DEFAULT_PRECODE;
 import static org.apache.zeppelin.jdbc.JDBCInterpreter.DEFAULT_STATEMENT_PRECODE;
@@ -510,6 +512,35 @@ void testAutoCompletion() throws IOException, InterpreterException {
     assertEquals(true, completionList.contains(correctCompletionKeyword));
   }
 
+  @Test
+  void testCreateOrUpdateSqlCompleterRestoresInterruptStatusOnTimeout() throws Exception {
+    Properties properties = new Properties();
+    properties.setProperty("common.max_count", "1000");
+    properties.setProperty("common.max_retry", "3");
+    properties.setProperty("default.driver", "org.h2.Driver");
+    properties.setProperty("default.url", getJdbcConnection());
+    properties.setProperty("default.user", "");
+    properties.setProperty("default.password", "");
+    JDBCInterpreter jdbcInterpreter = new JDBCInterpreter(properties);
+
+    // createOrUpdateSqlCompleter is private, so invoke it via reflection.
+    Method createOrUpdateSqlCompleter = JDBCInterpreter.class.getDeclaredMethod(
+        "createOrUpdateSqlCompleter", SqlCompleter.class, Connection.class, String.class,
+        String.class, int.class);
+    createOrUpdateSqlCompleter.setAccessible(true);
+
+    // Entering already interrupted makes awaitTermination throw InterruptedException
+    // immediately, deterministically hitting the catch block under test.
+    Thread.currentThread().interrupt();
+    try {
+      createOrUpdateSqlCompleter.invoke(jdbcInterpreter, null, null, DEFAULT_KEY, "sel", 3);
+      assertTrue(Thread.currentThread().isInterrupted());
+    } finally {
+      // Clear the interrupt flag so it doesn't leak into subsequent tests.
+      Thread.interrupted();
+    }
+  }
+
   private Properties getDBProperty(String dbPrefix,
                                    String dbUser,
                                    String dbPassowrd) throws IOException {