Buffered channels

Canonical guidance

• use buffering when capacity has real semantics
• keep backpressure behavior understandable
• prefer unbuffered channels when synchronization is the point

Use when

• bounded work queues
• semaphore-like throttling
• absorbing short producer-consumer bursts

Avoid

• choosing capacity by superstition
• increasing the buffer until flaky tests stop failing
• assuming buffering makes leaks or deadlocks impossible

Preferred pattern

sem := make(chan struct{}, 8)
sem <- struct{}{}

Anti-pattern

• adding a buffer just because the sender should “probably not block”

Explanation: This anti-pattern is tempting because blocking feels scary, but unexplained buffering often hides a design bug instead of fixing it.

Why

• buffer size is part of the concurrency design, not a cosmetic tuning knob