backpatch PR#2247 fix: handle ParameterStatus messages in QueryExecutorImpl.receiveFastpathResult

pgjdbc/src/main/java/org/postgresql/core/v3/QueryExecutorImpl.java

@@ -847,6 +847,19 @@ private void setSocketTimeout(int millis) throws PSQLException {
 
           break;
 
+        case 'S': // Parameter Status
+          try {
+            receiveParameterStatus();
+          } catch (SQLException e) {
+            if (error == null) {
+              error = e;
+            } else {
+              error.setNextException(e);
+            }
+            endQuery = true;
+          }
+          break;
+
         default:
           throw new PSQLException(GT.tr("Unknown Response Type {0}.", (char) c),
               PSQLState.CONNECTION_FAILURE);

pgjdbc/src/test/java/org/postgresql/jdbc/LargeObjectManagerTest.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2021, PostgreSQL Global Development Group
+ * See the LICENSE file in the project root for more information.
+ */
+
+package org.postgresql.jdbc;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import org.postgresql.largeobject.LargeObjectManager;
+import org.postgresql.test.TestUtil;
+import org.postgresql.util.PSQLException;
+import org.postgresql.util.PSQLState;
+
+import org.junit.jupiter.api.Test;
+
+import java.sql.Statement;
+
+class LargeObjectManagerTest {
+
+  /*
+   * It is possible for PostgreSQL to send a ParameterStatus message after an ErrorResponse
+   * Receiving such a message should not lead to an invalid connection state
+   * See https://github.com/pgjdbc/pgjdbc/issues/2237
+   */
+  @Test
+  public void testOpenWithErrorAndSubsequentParameterStatusMessageShouldLeaveConnectionInUsableStateAndUpdateParameterStatus() throws Exception {
+    try (PgConnection con = (PgConnection) TestUtil.openDB()) {
+      con.setAutoCommit(false);
+      String originalApplicationName = con.getParameterStatus("application_name");
+      try (Statement statement = con.createStatement()) {
+        statement.execute("begin;");
+        // Set transaction application_name to trigger ParameterStatus message after error
+        // https://www.postgresql.org/docs/14/protocol-flow.html#PROTOCOL-ASYNC
+        String updatedApplicationName = "LargeObjectManagerTest-application-name";
+        statement.execute("set application_name to '" + updatedApplicationName + "'");
+
+        LargeObjectManager loManager = con.getLargeObjectAPI();
+        try {
+          loManager.open(0, false);
+          fail("Succeeded in opening a non-existent large object");
+        } catch (PSQLException e) {
+          assertEquals(PSQLState.UNDEFINED_OBJECT.getState(), e.getSQLState());
+        }
+
+        // Should be reset to original application name
+        assertEquals(originalApplicationName, con.getParameterStatus("application_name"));
+      }
+    }
+  }
+}