pentaho/pentaho-kettle · error · KettleException

PentahoReportingOutput.Exception.UnexpectedErrorRenderingRep…

Error message

PentahoReportingOutput.Exception.UnexpectedErrorRenderingReport

What it means

processReport wraps any Throwable raised while rendering the report (loading the prpt file, preparing the output processor, writing the target) into a KettleException with message PentahoReportingOutput.Exception.UnexpectedErrorRenderingReport, including source and target filenames and the output type description. It is the catch-all guard of the reporting output step; the original exception is attached as the cause.

Solutions

Read the chained 'Caused by' exception — this wrapper only adds context; the cause identifies the real failure
Confirm the target file extension matches the selected output processor type (PDF->.pdf, Excel->.xls etc.)
Verify the source .prpt file exists, is readable, and was produced with a compatible Pentaho Reporting version
Check write permissions on the target directory and that the parent folder exists

Example fix

// before
new KettleException( BaseMessages.getString( PKG, "PentahoReportingOutput.Exception.UnexpectedErrorRenderingReport", ... ), e )
// after
// keep the wrapper, but log the cause explicitly before throwing to ease debugging:
logError( BaseMessages.getString( PKG, "PentahoReportingOutput.Exception.UnexpectedErrorRenderingReport",
  sourceFilename, targetFilename, outputProcessorType.getDescription() ), e );
throw new KettleException( BaseMessages.getString( PKG,
  "PentahoReportingOutput.Exception.UnexpectedErrorRenderingReport", sourceFilename,
  targetFilename, outputProcessorType.getDescription() ), e );

Defensive patterns

Strategy: try-catch

Validate before calling

FileObject src = KettleVFS.getInstance( bowl ).getFileObject( sourceFilename, transMeta );
if ( src == null || !src.exists() || !src.isReadable() ) {
  throw new KettleException( "Report source unreadable: " + sourceFilename );
}

Try / catch

try {
  step.processReport(...);
} catch ( KettleException e ) {
  Throwable root = e;
  while ( root.getCause() != null ) root = root.getCause();
  logError( "Render failed, root cause: " + root, root );
  throw e;
}

Prevention

Always match target file extension to the selected output processor type
Validate .prpt source files exist and load before production runs
Keep Pentaho Reporting engine and plugin versions aligned
Pre-create and permission-check the output directory

When it happens

Trigger: Any exception inside the try block of processReport: report file cannot be parsed, PdfReportUtil/OutputProcessor cannot handle the selected ProcessorType, VFS cannot open source or target file, or an error thrown inside the rendering pipeline.

Common situations: Corrupt or wrong-version .prpt report file; target filename with unsupported extension for the chosen processor type (e.g. PDF processor writing to .xlsx); missing write permissions on the output directory; classloader/resource issues in the plugin environment.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/77eb327bf7720dca. Report an issue: GitHub.

Appendix: source

Thrown at plugins/pentaho-reporting/impl/src/main/java/org/pentaho/di/trans/steps/pentahoreporting/PentahoReportingOutput.java:467

        if ( context.getStatusType() == StatusType.ERROR ) {
          KettleVFS.getInstance( getTransMeta().getBowl() ).getFileObject( targetFilename, getTransMeta() ).delete();
          if ( context.getCause() != null ) {
            throw context.getCause();
          }
          throw new KettleStepException( context.getMessage() );
        }

        ResultFile resultFile =
          new ResultFile(
            ResultFile.FILE_TYPE_GENERAL, KettleVFS.getInstance( getTransMeta().getBowl() )
            .getFileObject( targetFilename, getTransMeta() ),
            getTransMeta().getName(), getStepname() );
        resultFile.setComment( "This file was created with a Pentaho Reporting Output step" );
        addResultFile( resultFile );

      } catch ( Throwable e ) {
        throw new KettleException( BaseMessages.getString(
          PKG, "PentahoReportingOutput.Exception.UnexpectedErrorRenderingReport", sourceFilename, targetFilename,
          outputProcessorType.getDescription() ), e );
      }
    } finally {
      //Restore the original class loader
      Thread.currentThread().setContextClassLoader( old );
    }
  }

  private Class<?> findParameterClass( ReportParameterDefinition definition, String parameterName ) {
    for ( int i = 0; i < definition.getParameterCount(); i++ ) {
      ParameterDefinitionEntry entry = definition.getParameterDefinition( i );
      if ( parameterName.equals( entry.getName() ) ) {

        return entry.getValueType();
      }
    }
    return null;

View on GitHub (pinned to f3058517a1)