golang-context

1> **Community default.** A company skill that explicitly supersedes `samber/cc-skills-golang@golang-context` skill takes precedence.
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3# Go context.Context Best Practices
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5`context.Context` is Go's mechanism for propagating cancellation signals, deadlines, and request-scoped values across API boundaries and between goroutines. Think of it as the "session" of a request — it ties together every operation that belongs to the same unit of work.
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7## Best Practices Summary
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91. Propagate the same context through the entire request lifecycle: HTTP handler → service → DB → external APIs — any link that starts a fresh context keeps working after the client is gone.
102. Take `ctx` as the first parameter, named `ctx context.Context` — the fixed position is what makes context-aware APIs recognizable at a glance and what linters check.
113. Pass context through function parameters instead of storing it in a struct — the struct outlives the request that filled it, so later calls reuse a context that is already cancelled or belongs to someone else.
124. Pass `context.TODO()` rather than a `nil` context — `nil` panics on the first `Done()` or `Value()` call, far from the caller that passed it.
135. Call `cancel()` on all control-flow paths for `WithCancel`/`WithTimeout`/`WithDeadline`, unless ownership of the context and cancel function is explicitly returned or transferred — an uncalled `cancel()` keeps the child attached to its parent and leaks its timer until the parent finishes.
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