[CONJ-1011] correcting possible NPE when using statement.cancel() tha…

…t coincide with statement.close() in another thread
mariadb-corporation · Sep 30, 2022 · b6e80e2 · b6e80e2
1 parent 6cfdd7e
commit b6e80e2
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Showing 2 changed files with 8 additions and 7 deletions.
diff --git a/src/main/java/org/mariadb/jdbc/MariaDbStatement.java b/src/main/java/org/mariadb/jdbc/MariaDbStatement.java
@@ -785,7 +785,7 @@ public void close() throws SQLException {
       closed = true;
       if (results != null) {
         if (results.getFetchSize() != 0) {
-          skipMoreResults();
+          skipMoreResults(protocol);
         }
 
         results.close();
@@ -972,17 +972,19 @@ public void setLocalInfileInputStream(InputStream inputStream) throws SQLExcepti
    *     <code>Statement</code>
    */
   public void cancel() throws SQLException {
+    // use local protocol variable, in case statement is closed during cancellation
+    Protocol initialProtocol = this.protocol;
     checkClose();
     boolean locked = lock.tryLock();
     try {
       if (executing) {
-        protocol.cancelCurrentQuery();
+        initialProtocol.cancelCurrentQuery();
       } else if (results != null
           && results.getFetchSize() != 0
-          && !results.isFullyLoaded(protocol)) {
+          && !results.isFullyLoaded(initialProtocol)) {
         try {
-          protocol.cancelCurrentQuery();
-          skipMoreResults();
+          initialProtocol.cancelCurrentQuery();
+          skipMoreResults(initialProtocol);
         } catch (SQLException e) {
           // eat exception
         }
@@ -1186,7 +1188,7 @@ public long getLargeUpdateCount() {
     return -1;
   }
 
-  protected void skipMoreResults() throws SQLException {
+  protected void skipMoreResults(Protocol protocol) throws SQLException {
     try {
       protocol.skip();
       warningsCleared = false;

diff --git a/src/main/java/org/mariadb/jdbc/internal/protocol/AbstractQueryProtocol.java b/src/main/java/org/mariadb/jdbc/internal/protocol/AbstractQueryProtocol.java
@@ -397,7 +397,6 @@ public boolean executeBatchClient(
         // INSERT INTO X(a,b) VALUES (1,2), (3,4), ...
         executeBatchRewrite(results, prepareResult, parametersList, true);
         return true;
-
       }
 
       if (options.useBulkStmts