apache/iceberg · warning

Failed to scan delegate parser in {}:

Error message

Failed to scan delegate parser in {}: 

What it means

ExtendedParser scans a Spark parser object's class hierarchy for an embedded delegate ParserInterface so its SQL can be re-parsed. When reflection cannot find or access such a field, it logs this warning and returns null instead of throwing, since the enclosing operation can usually proceed without delegate extraction.

Source

Thrown at spark/v3.5/spark/src/main/java/org/apache/iceberg/spark/ExtendedParser.java:99

    return null;
  }

  private static ParserInterface getNextDelegateParser(ParserInterface parser) {
    try {
      Class<?> clazz = parser.getClass();
      while (clazz != null) {
        for (Field field : clazz.getDeclaredFields()) {
          field.setAccessible(true);
          Object value = field.get(parser);
          if (value instanceof ParserInterface && value != parser) {
            return (ParserInterface) value;
          }
        }
        clazz = clazz.getSuperclass();
      }
    } catch (Exception e) {
      log().warn("Failed to scan delegate parser in {}: ", parser.getClass().getName(), e);
    }

    return null;
  }

  private static Logger log() {
    return LoggerFactory.getLogger(ExtendedParser.class);
  }

  List<RawOrderField> parseSortOrder(String orderString) throws AnalysisException;
}

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Verify the Spark version is one supported by the Iceberg spark/v3.5 module; internal parser fields are version-specific.
2. Check the WARN log's attached exception stack to see whether it is NoSuchFieldException (expected, harmless) vs SecurityException (fix JVM security policy).
3. If the warning is benign noise on your Spark build, ignore it — the method returns null and callers fall back gracefully.
4. File/track an Iceberg issue if a newer Spark minor release changed parser internals so the reflection targets can be updated.

Example fix

// before: reflection fails on unexpected Spark internals
ParserInterface delegate = ExtendedParser.findParser(sqlParser);
// after: guard for null and fall back
ParserInterface delegate = ExtendedParser.findParser(sqlParser);
if (delegate == null) {
  // proceed without delegate re-parsing
}

ParserInterface delegate = ExtendedParser.findParser(sqlParser);
if (delegate == null) { /* proceed without delegate re-parsing */ }

if (delegate instanceof ParserInterface p) { use(p); }

try { delegate = ExtendedParser.findParser(parser); } catch (RuntimeException e) { delegate = null; }

When it happens

Trigger: Calling ExtendedParser.findParser (via getNextDelegateParser) on a Spark parser implementation whose class hierarchy exposes no field assignable to ParserInterface, or where accessing the field throws (SecurityException, IllegalAccessException).

Common situations: Spark version upgrades that restructure the internal parser delegation chain; custom Spark builds or shaded Spark distributions where field layout differs; running under a SecurityManager that blocks reflective access.

Understand the failure class

Background: "is deprecated and will be removed" — deprecation warnings for old API names, keywords, and options, and how to migrate before the removal release — this error's family across 29 libraries.

Related errors

• Failed to scan delegate parser in {}:
• Deleted only {} of {} files using bulk deletes
• Failed to delete file: {}
• Failure during rewrite process for group {}
• {} is true but {} rewrite commits failed. Check the logs to

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/c7623974d73351af. Report an issue: GitHub.