MuntashirAkon/AppManager · error · IOException

Failed to read Paxheader. Expected

Error message

Failed to read Paxheader. Expected ${restLen} bytes, read ${got}

What it means

Thrown by TarUtils.parsePaxHeaders when IOUtils.readFully cannot read the declared restLen bytes of a PAX keyword's value from the stream, i.e. the stream hit EOF prematurely. The PAX record promised more data than the stream contains.

Solutions

1. Check the archive file size against the expected size and re-download if truncated
2. Validate the source stream isn't closed or failing upstream
3. Catch IOException and treat the archive as corrupt
4. Re-create the archive with a standard tar tool

long expectedSize = getExpectedArchiveSize();
if (archiveFile.length() != expectedSize) {
    throw new IOException("Archive truncated: " + archiveFile.length() + " of " + expectedSize + " bytes");
}

try {
    // read tar
} catch (IOException e) {
    if (e.getMessage().startsWith("Failed to read Paxheader")) {
        throw new TruncatedArchiveException("Download incomplete", e);
    }
    throw e;
}

When it happens

Trigger: Reading a TAR whose PAX header value length field is larger than the actual remaining stream bytes; happens on truncated downloads or when the underlying InputStream ends mid PAX record.

Common situations: Incomplete file downloads, archives cut off by interrupted transfers or partial uploads, reading from a closed/socket stream that ended early.

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

• Unexpected EOF when reading parse information of 1.X PAX…
• Error detected parsing the pax header
• Failed to read Paxheader. Encountered a non-number while…
• Failed to read Paxheader.GNU.sparse.offset is expected…
• Failed to read Paxheader.Value should end with a newline

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/a77807b5e3f83acf. Report an issue: GitHub.

Appendix: source

Thrown at app/src/main/java/org/apache/commons/compress/archivers/tar/TarUtils.java:716

                        totalRead++;
                        if (totalRead < 0 || (headerSize >= 0 && totalRead >= headerSize)) {
                             break;
                         }
                        if (ch == '='){ // end of keyword
                            final String keyword = coll.toString(CharsetNames.UTF_8);
                            // Get rest of entry
                            final int restLen = len - read;
                            if (restLen <= 1) { // only NL
                                headers.remove(keyword);
                            } else if (headerSize >= 0 && restLen > headerSize - totalRead) {
                                throw new IOException("Paxheader value size " + restLen
                                    + " exceeds size of header record");

                            } else {
                                final byte[] rest = new byte[restLen];
                                final int got = IOUtils.readFully(inputStream, rest);
                                if (got != restLen) {
                                    throw new IOException("Failed to read "
                                            + "Paxheader. Expected "
                                            + restLen
                                            + " bytes, read "
                                            + got);
                                }
                                totalRead += restLen;
                                // Drop trailing NL
                                if (rest[restLen - 1] != '\n') {
                                    throw new IOException("Failed to read Paxheader."
                                       + "Value should end with a newline");
                                }
                                final String value = new String(rest, 0,
                                        restLen - 1, StandardCharsets.UTF_8);
                                headers.put(keyword, value);

                                // for 0.0 PAX Headers
                                if (keyword.equals("GNU.sparse.offset")) {
                                    if (offset != null) {

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