Confinement

Canonical guidance

• prefer ownership over shared mutation
• communicate with the owner rather than poking at its state
• transfer ownership deliberately when needed

Use when

• caches or aggregators with one logical owner
• event loops
• state machines with serialized updates

Avoid

• a “mostly owned” structure that many goroutines still mutate directly
• mixing channel requests with unsynchronized side access
• exporting internal mutable references casually

Preferred pattern

• one goroutine owns a map and serves reads or writes through requests

Anti-pattern

• a worker owns a queue but other goroutines also append to the backing slice directly

Explanation: This is tempting because the direct access is short, but it breaks the whole ownership story.

Why

• confinement removes entire classes of synchronization bugs