MuntashirAkon/AppManager · error · IOException

Gzip-compressed data is corrupt

Error message

Gzip-compressed data is corrupt

What it means

read() feeds data through java.util.zip.Inflater; when inflate() raises DataFormatException, the deflate stream is malformed and the library rethrows it as IOException("Gzip-compressed data is corrupt"). This is the generic mid-stream corruption/invalid-deflate-data error.

Solutions

  1. Re-acquire the file and verify a checksum (e.g. md5sum against the source) to confirm corruption.
  2. Check whether the stream is truncated — if the transfer can be retried/range-resumed, redo it.
  3. Wrap reads in try-catch for IOException to fail gracefully and surface the corrupt-input condition to the operator.

Example fix

// before
InputStream gz = new GzipCompressorInputStream(in);
IOUtils.copy(gz, out);
// after
try (InputStream gz = new GzipCompressorInputStream(in)) {
    IOUtils.copy(gz, out);
} catch (IOException e) {
    if (e.getMessage().contains("corrupt")) {
        throw new IOException("Source file damaged; re-fetch and verify checksum", e);
    }
    throw e;
}
Defensive patterns

Strategy: try-catch

Try / catch

try (InputStream gz = new GzipCompressorInputStream(rawIn)) {
    IOUtils.copy(gz, out);
} catch (IOException e) {
    if (e.getMessage().contains("Gzip-compressed data is corrupt")) {
        // input corrupted mid-stream: retry from a verified source, do not retry blindly
        throw new IOException("corrupt gzip payload; re-fetch source", e);
    }
    throw e;
}

Prevention

When it happens

Trigger: Truncated or bit-corrupted deflate blocks; decoding a file that is not actually deflate-compressed after a valid-looking header; stream read offset desynchronization (e.g. skipped header bytes incorrectly).

Common situations: Incomplete downloads/interrupted transfers; decoding multi-part files joined incorrectly; storage media corruption; parsing a .gz whose header parsed but body was replaced.

Understand the failure class

Background: Checksum mismatch errors: "checksum verification failed", "digest mismatch", "expected vs actual checksum" — what they mean and how to fix them — this error's family across 41 libraries.

Related errors

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/e6cd7b6595629e59. Report an issue: GitHub.

Appendix: source

Thrown at app/src/main/java/org/apache/commons/compress/compressors/gzip/GzipCompressorInputStream.java:297

        while (len > 0) {
            if (inf.needsInput()) {
                // Remember the current position because we may need to
                // rewind after reading too much input.
                in.mark(buf.length);

                bufUsed = in.read(buf);
                if (bufUsed == -1) {
                    throw new EOFException();
                }

                inf.setInput(buf, 0, bufUsed);
            }

            final int ret;
            try {
                ret = inf.inflate(b, off, len);
            } catch (final DataFormatException e) { // NOSONAR
                throw new IOException("Gzip-compressed data is corrupt");
            }

            crc.update(b, off, ret);
            off += ret;
            len -= ret;
            size += ret;
            count(ret);

            if (inf.finished()) {
                // We may have read too many bytes. Rewind the read
                // position to match the actual amount used.
                in.reset();

                final int skipAmount = bufUsed - inf.getRemaining();
                if (IOUtils.skip(in, skipAmount) != skipAmount) {
                    throw new IOException();
                }

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