What causes "size mismatch: got %d, expected %d (update runtime.json)" in xtekky/gpt4free?

Check the real artifact size (curl -sI | grep -i content-length) and update spec.Size in runtime.json

size mismatch: got %d, expected %d (update runtime.json)

Error message

size mismatch: got %d, expected %d (update runtime.json)

What it means

After a successful download and rename to the cache path, downloadRuntime in g4f-go/download.go stats the file and compares its size to spec.Size from runtime.json. A mismatch aborts with 'size mismatch: got %d, expected %d (update runtime.json)' — the manifest's pinned size no longer matches the artifact actually served.

Source

Thrown at g4f-go/download.go:147

		copyErr = cerr
	}
	if copyErr != nil {
		os.Remove(partName(binDir))
		return fmt.Errorf("download interrupted: %w", copyErr)
	}
	if err := os.Rename(partName(binDir), cachePath); err != nil {
		os.Remove(partName(binDir))
		return err
	}
	fmt.Printf("runtime: downloaded %s in %s\n", humanBytes(total), time.Since(start).Round(time.Second))

	if spec.Size > 0 {
		fi, err := os.Stat(cachePath)
		if err != nil {
			return err
		}
		if fi.Size() != spec.Size {
			return fmt.Errorf("size mismatch: got %d, expected %d (update runtime.json)", fi.Size(), spec.Size)
		}
	}
	return verifyRuntime(cachePath, spec)
}

// verifyRuntime validates sha256 when pinned in the manifest.
func verifyRuntime(cachePath string, spec *RuntimeSpec) error {
	if spec.SHA256 == "" {
		return nil // unpinned; trust size/transport
	}
	f, err := os.Open(cachePath)
	if err != nil {
		return err
	}
	defer f.Close()
	h := sha256.New()
	if _, err := io.Copy(h, f); err != nil {
		return err

View on GitHub (pinned to 973504e177)

Solutions

Check the real artifact size (curl -sI <spec.URL> | grep -i content-length) and update spec.Size in runtime.json
Refresh your runtime.json from the upstream repo so size and sha256 match the current release
If the served bytes look wrong (small/HTML), suspect a broken mirror and use the official URL
Clear the cached download (.g4f-runtime/runtime.download / cache file) and retry after fixing the manifest

Example fix

// before
// size mismatch: got 29140615, expected 29999872 (update runtime.json)

// after
// runtime.json
"platforms": {
  "linux-x64": {
    "url": "https://host/runtime-linux-x64.tar.gz",
    "size": 29140615,   // corrected
    "sha256": "..."     // recompute: sha256sum runtime-linux-x64.tar.gz
  }
}

Defensive patterns

Strategy: validation

Validate before calling

resp, err := http.Head(spec.URL)
if err == nil {
    if cl := resp.Header.Get("Content-Length"); cl != "" {
        if n, _ := strconv.ParseInt(cl, 10, 64); n != spec.Size {
            // manifest stale: fix runtime.json before downloading
        }
    }
}

Try / catch

err := downloadRuntime(binDir, cachePath, spec)
if err != nil && strings.Contains(err.Error(), "size mismatch") {
    // re-pin spec.Size (and sha256) in runtime.json to the current artifact
}

Prevention

Regenerate size AND sha256 together whenever you re-publish an artifact
Automate manifest generation from the built artifact instead of hand-editing
Use immutable, content-addressed URLs so sizes never drift under a pinned manifest

When it happens

Trigger: The hosting server silently re-uploaded/replaced the runtime archive while runtime.json still pins the old size; a truncated-but-200 response (rare when Content-Length is honored); or a locally edited manifest with a stale size.

Common situations: Upstream re-publishes an asset without cutting a new manifest; users editing runtime.json by hand; CDN serving a different (e.g. HTML error) body that still returned 200.

Related errors

AI-assisted analysis of xtekky/gpt4free@973504e177 (2026-08-14). Data as JSON: /api/errors/7b11345acc884529. Report an issue: GitHub.