contextpolicy

What it detects

Reports context.Context parameters that are not first, contexts stored in structs, and calls that pass a definitely nil context. In supported test code, it also prefers t.Context() or b.Context() over context.Background().

Checks

Check	What it detects
context-first	Reports context.Context parameters that are not first.
context-storage	Reports context.Context values stored in structs.
test-context*	Reports tests that use context.Background instead of the testing handle’s context.
nil-context	Reports definitely nil context.Context arguments.

* Opt-in; requires explicit selection.

Why this is flagged

Keeping context.Context as the first parameter makes cancellation and deadlines easy to pass through a call chain. Storing a context or passing nil can give it the wrong lifetime or cause failures far from the call site.

Further reading: Package context, Contexts and structs.

How to fix it

Accept the context as the function’s first parameter and pass it directly to the work that needs it. Do not store it in a struct or pass nil; use an appropriate real context, such as the test’s context in test code.

Examples

Flagged code

Context parameter order

// gohawk: context.Context must be first parameter
func LoadUser(id string, ctx context.Context) error {
  return nil
}

Context stored in a struct

type Request struct {
  // gohawk: do not store context.Context in a struct
  Context context.Context
}

Nil context argument

func acceptContext(context.Context) {}

func loadWithoutContext() {
  // gohawk: do not pass nil context.Context
  acceptContext(nil)
}

Accepted code

func LoadUserCorrectly(ctx context.Context, id string) error {
  return nil
}

Options

Knob	Default	Effect
prefer-test-context	true	Prefer t.Context or b.Context over context.Background in tests.