NullPointerException in COSName.getString

[THausherr]

I sometimes get this:

org.verapdf.core.ValidationException: Caught unexpected runtime exception during validation
at org.verapdf.pdfa.validation.validators.BaseValidator.validate(BaseValidator.java:110)
at org.apache.pdfbox.examples.pdfa.MergePDFATest.testMergePDFA(MergePDFATest.java:83)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at java.base/java.util.concurrent.RecursiveAction.exec(RecursiveAction.java:189)
at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:183)
Caused by: java.lang.NullPointerException
at org.verapdf.cos.COSName.getString(COSName.java:112)
at org.verapdf.parser.postscript.PSOperator.(PSOperator.java:44)
at org.verapdf.parser.postscript.PSObject.getPSObject(PSObject.java:72)
at org.verapdf.parser.COSParser.nextObject(COSParser.java:110)
at org.verapdf.pd.font.cmap.CMapParser.processObject(CMapParser.java:93)
at org.verapdf.pd.font.cmap.CMapParser.parse(CMapParser.java:80)
at org.verapdf.pd.font.cmap.CMapFactory.getCMap(CMapFactory.java:60)
at org.verapdf.pd.font.cmap.PDCMap.getCMapFile(PDCMap.java:128)
at org.verapdf.pd.font.cmap.PDCMap.getCMapFile(PDCMap.java:111)
at org.verapdf.pd.font.PDType0Font.(PDType0Font.java:63)
at org.verapdf.factory.fonts.PDFontFactory.getPDFont(PDFontFactory.java:65)
at org.verapdf.pd.PDResources.getFont(PDResources.java:146)
at org.verapdf.gf.model.impl.pd.util.PDResourcesHandler.getFont(PDResourcesHandler.java:103)
at org.verapdf.gf.model.impl.pd.util.PDResourcesHandler.getFont(PDResourcesHandler.java:89)
at org.verapdf.gf.model.factory.operators.OperatorParser.parseOperator(OperatorParser.java:366)
at org.verapdf.gf.model.factory.operators.OperatorFactory.operatorsFromTokens(OperatorFactory.java:113)
at org.verapdf.gf.model.impl.pd.GFPDContentStream.parseOperators(GFPDContentStream.java:152)
at org.verapdf.gf.model.impl.pd.GFPDContentStream.isContainsTransparency(GFPDContentStream.java:195)
at org.verapdf.gf.model.impl.pd.GFPDPage.parseContentStream(GFPDPage.java:248)
at org.verapdf.gf.model.impl.pd.GFPDPage.getContentStream(GFPDPage.java:228)
at org.verapdf.gf.model.impl.pd.GFPDPage.getLinkedObjects(GFPDPage.java:132)
at org.verapdf.pdfa.validation.validators.BaseValidator.addAllLinkedObjects(BaseValidator.java:232)
at org.verapdf.pdfa.validation.validators.BaseValidator.checkNext(BaseValidator.java:199)
at org.verapdf.pdfa.validation.validators.BaseValidator.validate(BaseValidator.java:144)
at org.verapdf.pdfa.validation.validators.BaseValidator.validate(BaseValidator.java:108)
... 8 more

The file is ok:
Merged_PDFA.pdf

Version used:

    <dependency>
        <groupId>org.verapdf</groupId>
        <artifactId>validation-model-jakarta</artifactId>
        <version>1.26.1</version>
        <scope>test</scope>
    </dependency>

Code:

VeraGreenfieldFoundryProvider.initialise();
PDFAFlavour flavour = PDFAFlavour.fromString("1b");
try (PDFAParser parser = Foundries.defaultInstance().createParser(new File(pdfaMergedFilename), flavour))
{
    PDFAValidator validator = Foundries.defaultInstance().createValidator(flavour, false);
    ValidationResult veraResult = validator.validate(parser);
    assertTrue(veraResult.isCompliant());
}

I wonder if this could be because verapdf is called twice and in parallel in this build test (the other code is the same)

[bdoubrov]

@THausherr thanks a lot for reporting this issue.

In general, we aim to guarantee that veraPDF can run validation of several files in parallel, keeping all cached data from PDF parser thread local. We'll do more tests, but so far were able to reproduce this problem if the same PDF file is parsed in parallel. Is this also the case of your tests? Or you get this error even if different files are validated at the same time?

[THausherr]

No it's not the same file.