oracle/graal · error · ExperimentParserError

Failed to parse experiment {experimentId} in {resource}: {me

Error message

Failed to parse experiment {experimentId} in {resource}: {message}

What it means

ExperimentJSONParser.parse wraps any JsonParserException raised while parsing a whole file's JSON into ExperimentParserError, carrying the experiment id, the file's symbolic path, and the parser's position-tagged message. It means the file is not syntactically valid JSON at all (as opposed to a type mismatch inside valid JSON).

Source

Thrown at compiler/src/org.graalvm.profdiff/src/org/graalvm/profdiff/parser/ExperimentJSONParser.java:180

     */
    private final FileView file;

    public ExperimentJSONParser(ExperimentId experimentId, FileView file) {
        this.experimentId = experimentId;
        this.file = file;
    }

    /**
     * Parses the source string as a JSON literal.
     *
     * @return the parsed JSON literal
     * @throws ExperimentParserError failed to parse the experiment
     */
    public JSONLiteral parse() throws ExperimentParserError, IOException {
        try {
            return new JSONLiteral(new JsonParser(file.readFully()).parse(), null);
        } catch (JsonParserException parserException) {
            throw new ExperimentParserError(experimentId, file.getSymbolicPath(), parserException.getMessage());
        }
    }

    /**
     * Parses the source string as a JSON map using a list of allowed keys. It is assumed that the
     * source string comes from the assigned file view.
     *
     * @param allowedKeys the list of allowed keys
     * @param source the source string containing the JSON map
     * @return the parsed JSON map containing only values for (not necessarily all) allowed keys
     * @throws ExperimentParserError failed to parse the experiment
     * @see JsonParser#parseAllowedKeys(List)
     */
    public JSONMap parseAllowedKeys(List<String> allowedKeys, String source) throws ExperimentParserError, IOException {
        try {
            return new JSONMap(new JsonParser(source).parseAllowedKeys(allowedKeys));
        } catch (JsonParserException parserException) {
            throw new ExperimentParserError(experimentId, file.getSymbolicPath(), parserException.getMessage());

View on GitHub (pinned to a66e9ccd1d)

Solutions

1. Open the named file at the character position in the parser message and inspect the syntax error.
2. Regenerate the log from a clean, completed run.
3. If hand-assembling logs, keep exactly one JSON value per line for optimization logs and one document for proftool output.
4. Check disk space / process exit status of the original run.

// Pre-validate JSON syntax with the same parser used internally
try {
    new org.graalvm.profdiff.utils.JsonParser(source).parse();
} catch (JsonParserException e) {
    throw new IllegalArgumentException("Invalid JSON in " + path + ": " + e.getMessage());
}

try {
    parser.parse();
} catch (ExperimentParserError e) {
    // contains the JsonParserException message with line/column; fix or regenerate the file
}

When it happens

Trigger: A truncated or concatenated-wrongly optimization-log file (units are newline-separated JSON), binary garbage, HTML error pages saved as logs, or a proftool output cut off mid-write.

Common situations: Logs truncated by a killed JVM or full disk; files transferred with encoding corruption; multiple JSON documents concatenated without the expected newline framing; appending to an existing log with a partial line.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• Failed to parse experiment {experimentId} in compilation uni
• Failed to parse experiment {experimentId} in {resource}: exp
• Failed to parse experiment {experimentId} in {resource}: exp
• Could not read the files of the experiment {experimentId}: {
• Error loading phase plan from %s

AI-assisted analysis of oracle/graal@a66e9ccd1d (2026-08-14). Data as JSON: /api/errors/9bbe07d1911fe176. Report an issue: GitHub.