quarkusio/quarkus · error · IllegalArgumentException

Count (${count}) must be >= 0: ${file}

Error message

Count (${count}) must be >= 0: ${file}

What it means

IllegalArgumentException from the PathPart constructor: a partial-path response was requested with a negative byte count. The same existence/readability/offset/count validation as FilePart applies; the count argument is the value at fault.

Source

Thrown at independent-projects/resteasy-reactive/common/runtime/src/main/java/org/jboss/resteasy/reactive/PathPart.java:45

    /**
     * Create a new partial {@link Path} object.
     *
     * @param file The file to send
     * @param offset The starting byte of the file (must be >= 0)
     * @param count The number of bytes to send (must be >= 0 and offset+count <= file size)
     */
    public PathPart(Path file, long offset, long count) {
        if (!Files.exists(file))
            throw new IllegalArgumentException("File does not exist: " + file);
        if (!Files.isRegularFile(file))
            throw new IllegalArgumentException("File is not a regular file: " + file);
        if (!Files.isReadable(file))
            throw new IllegalArgumentException("File cannot be read: " + file);
        if (offset < 0)
            throw new IllegalArgumentException("Offset (" + offset + ") must be >= 0: " + file);
        if (count < 0)
            throw new IllegalArgumentException("Count (" + count + ") must be >= 0: " + file);
        long fileLength;
        try {
            fileLength = Files.size(file);
            if ((offset + count) > fileLength)
                throw new IllegalArgumentException(
                        "Offset + count (" + (offset + count) + ") larger than file size (" + fileLength + "): " + file);
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
        this.file = file;
        this.offset = offset;
        this.count = count;
    }
}

View on GitHub (pinned to e1c734241f)

Solutions

1. Compute count as `Math.max(0, end - start)` or validate `end >= start` before construction.
2. For 'rest of file' semantics, read the file size with `Files.size(file)` and compute `count = fileSize - offset` instead of using -1.
3. Return 416 Range Not Satisfiable when the parsed range is invalid rather than constructing the part.

Example fix

// before
PathPart part = new PathPart(file, start, -1); // 'until end'
// after
long fileSize = Files.size(file);
long count = fileSize - start;
PathPart part = new PathPart(file, start, count);

long fileSize = Files.size(file);
if (offset < 0 || end < offset || end >= fileSize) {
    return Response.status(Response.Status.REQUESTED_RANGE_NOT_SATISFIABLE).build();
}
long count = end - offset + 1;

boolean isValidRange(long offset, long count) {
    return offset >= 0 && count >= 0;
}

try {
    return Response.ok(new PathPart(file, offset, count)).build();
} catch (IllegalArgumentException e) {
    return Response.status(Response.Status.REQUESTED_RANGE_NOT_SATISFIABLE).build();
}

When it happens

Trigger: Calling `new PathPart(file, offset, count)` with a negative count, usually from computing `end - start` where end < start, or passing -1 as 'until end of file'.

Common situations: Range header parsing where the client sends `bytes=500-100` (start > end); using -1 as an 'unbounded' convention; off-by-one in end index computation.

Related errors

• Offset (${offset}) must be >= 0: ${file}
• Offset + count (${offset + count}) larger than file size (${
• An attachment must contain either a file or a raw data
• seconds cannot be negative
• seconds cannot be negative

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/b00be8485bcb1e9a. Report an issue: GitHub.