backpatch PR#2247 (#2249)

* backpatch PR#2247
QueryExecutorImpl.receiveFastpathResult did not properly handle ParameterStatus messages.
This in turn caused failures for some LargeObjectManager operations.
Fixed by adding the missing code path, based on the existing handling in processResults.

Closes #2237
Original by Simon Strassl https://github.com/strassl

* Fix test

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"));
+      }
+    }
+  }
+}