nats-io/nats-server · error

Error decoding sources state: %s

Error message

Error decoding sources state: %s

What it means

A warning logged by recoverSourcesState() when the sources index file exists but fails to decode. The file is deleted and in-memory sources state reset, so recovery continues with sources sequence tracking restarted rather than failing stream startup.

Source

Thrown at server/filestore.go:12487

}

// Lock should be held.
func (fs *fileStore) recoverSourcesState() uint64 {
	// See if we have a sources index file.
	fs.dios.acquire()
	fn := fs.sourcesStatePath()
	buf, err := os.ReadFile(fn)
	fs.dios.release()

	if err != nil && !os.IsNotExist(err) {
		fs.warn("Recovering sources state from index errored: %v", err)
	}

	var sourcesSeq uint64
	if err == nil {
		sourcesSeq, err = fs.decodeSourcesState(buf)
		if err != nil {
			fs.warn("Error decoding sources state: %s", err)
			// Remove the file, and reset collected state (if any).
			_ = os.Remove(fn)
			fs.sources = nil
		}
	}

	if sourcesSeq < fs.state.FirstSeq {
		sourcesSeq = fs.state.FirstSeq
	}
	return sourcesSeq
}

var errSourcesInvalidVersion = errors.New("sources: encoded version not known")

func (fs *fileStore) decodeSourcesState(b []byte) (uint64, error) {
	if len(b) < sourcesHeaderLen {
		return 0, io.ErrShortBuffer
	}

View on GitHub (pinned to 3a66a489d2)

Solutions

1. The corrupt file is removed automatically; verify it regenerates on next run
2. Check the store directory for disk corruption or version-format mismatch
3. Re-sync mirror/source streams if sequence continuity was lost

When it happens

Trigger: Thrown at server/filestore.go:12487 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/bb2cbf0f673251e6. Report an issue: GitHub.