oracle/graal · error · IOException

The provided optimization log path does not denote a directo

Error message

The provided optimization log path does not denote a directory

What it means

ExperimentFilesImpl.getOptimizationLogs throws IOException when File.listFiles() on the configured --optimization-log path returns null, which the JDK does when the path is not a directory (or is unreadable). profdiff requires the optimization log to be a directory of JSON files, one compilation unit sequence per line.

Source

Thrown at compiler/src/org.graalvm.profdiff/src/org/graalvm/profdiff/parser/ExperimentFilesImpl.java:97

        if (proftoolOutputPath == null) {
            return Optional.empty();
        }
        return Optional.of(FileView.fromFile(new File(proftoolOutputPath)));
    }

    /**
     * Gets an iterable of file views representing the optimization log. Each file view may contain
     * several JSON-encoded compilation units separated by a {@code '\n'}. Individual files are
     * discovered by listing the files in the provided {@link #optimizationLogPath}.
     *
     * @return an iterable of file views representing an optimization log
     * @throws IOException the optimization log is not a directory
     */
    @Override
    public Iterable<FileView> getOptimizationLogs() throws IOException {
        File[] files = new File(optimizationLogPath).listFiles();
        if (files == null) {
            throw new IOException("The provided optimization log path does not denote a directory");
        }
        return () -> Arrays.stream(files).map(FileView::fromFile).iterator();
    }

    @Override
    public Experiment.CompilationKind getCompilationKind() {
        return compilationKind;
    }

    @Override
    public ExperimentId getExperimentId() {
        return experimentId;
    }
}

View on GitHub (pinned to a66e9ccd1d)

Solutions

1. Pass the directory that directly contains the optimization-log JSON files.
2. Confirm the path exists and is readable: 'ls <path>' must list the files.
3. If you only have a single file, put it in an empty directory and pass that directory.

Example fix

# before
mx profdiff normal-tier --experiment1 exp1 --proftool1 p1.json --optimization-log1 optlog1.json
# after
mx profdiff normal-tier --experiment1 exp1 --proftool1 p1.json --optimization-log1 dir-with-optlogs/

File dir = new File(optimizationLogPath);
if (!dir.isDirectory() || !dir.canRead()) {
    throw new IllegalArgumentException("--optimization-log must be a readable directory: " + optimizationLogPath);
}

static boolean isReadableLogDirectory(String path) {
    File f = new File(path);
    return f.isDirectory() && f.canRead() && f.list() != null;
}

try {
    for (FileView fv : experimentFiles.getOptimizationLogs()) { /* ... */ }
} catch (IOException e) {
    if (e.getMessage().contains("does not denote a directory")) { /* fix the path */ }
}

When it happens

Trigger: Passing a file path instead of a directory to --optimization-log, a path that does not exist, or a directory the process cannot read/list.

Common situations: Users zipping up a single optimization log file and passing that; wrong relative path from a different working directory; typos in the path; the directory removed by cleanup scripts between runs.

Related errors

• Failed to print the optimization log to a file: %s
• Could not read the files of the experiment {experimentId}: {
• Invalid directed inlining rules file path: {path}
• Failed to parse experiment {experimentId} in compilation uni
• Failed to parse experiment {experimentId} in {resource}: exp

AI-assisted analysis of oracle/graal@a66e9ccd1d (2026-08-14). Data as JSON: /api/errors/20e8714ee4030408. Report an issue: GitHub.