resourcelifetime

What it detects

Release owned resources on every path. Storing a resource in a partially constructed object does not transfer ownership when an error path returns without that object.

The built-in contracts cover files, transactions, SQL rows and statements, HTTP response bodies, timers and tickers, and gzip/zlib readers and writers.

Checks

Check	What it detects
missing-release	Reports owned resources that are not released on every return path.

Why this is flagged

Owned resources are limited and often hold work open elsewhere. Missing cleanup on even one return path can leak file descriptors, database connections, network bodies, timers, or transactions until the program slows down or fails.

Further reading: Effective Go: Defer, Package net/http.

How to fix it

As soon as a resource is acquired successfully, arrange for its matching cleanup on every later return path. Use defer when the current function owns the resource, or transfer it only when the receiver clearly takes ownership.

Examples

Flagged code

Leaked file

func read(path string) error {
  // gohawk: owned resource from os.Open is not released on every return path
  file, err := os.Open(path)
  if err != nil {
    return err
  }
  _ = file
  return nil
}

Leaked database rows

func query(ctx context.Context, database *sql.DB) error {
  // gohawk: owned resource from sql.QueryContext is not released on every return path
  rows, err := database.QueryContext(ctx, "SELECT 1")
  if err != nil {
    return err
  }
  _ = rows
  return nil
}

Accepted code

func readSafely(path string) error {
  file, err := os.Open(path)
  if err != nil {
    return err
  }
  defer file.Close()
  return nil
}

Options

Knob	Default	Effect
contracts	os,http,sql,time,compress	Comma-separated resource contract families: os,http,sql,time,compress.
require-reader-close	true	Require gzip and zlib readers to be closed.