code: func supportsShallowClone(remoteURL string) bool {
  	if urlutil.IsURL(remoteURL) {
  		// Check if the HTTP server is smart
  
  		// Smart servers must correctly respond to a query for the git-upload-pack service
  		serviceURL := remoteURL + "/info/refs?service=git-upload-pack"
  
  		// Try a HEAD request and fallback to a Get request on error
  		res, err := http.Head(serviceURL)
  		if err != nil || res.StatusCode != http.StatusOK {
  			res, err = http.Get(serviceURL)
  			if err == nil {
  				res.Body.Close()
  			}
  			if err != nil || res.StatusCode != http.StatusOK {
  				// request failed
  				return false
  			}
  		}
  
  		if res.Header.Get("Content-Type") != "application/x-git-upload-pack-advertisement" {
  			// Fallback, not a smart server
  			return false
  		}
  		return true
  	}
  	// Non-HTTP protocols always support shallow clones
  	return true
  }
docs: // Check if a given git URL supports a shallow git clone,
  // i.e. it is a non-HTTP server or a smart HTTP server.