fix: stop NewSubscriptionID from colliding#172
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Replace time.Now().UnixNano() with a monotonic atomic counter. The clock-based scheme collides on coarse-resolution clocks (commonly macOS, where consecutive calls in a tight loop return the same nanosecond), which surfaced as a persistent TestSubscriptionID_UniqueIDs failure on local test runs. The counter keeps the existing "sessionID-msgType-identifier" string format and Unwrap semantics unchanged - the identifier segment was already treated as an opaque string by consumers. Co-Authored-By: Claude
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Go Test coverage is 53.3 %\ ✨ ✨ ✨ |
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Might not matter unless doing local dev without docker.
Summary
`NewSubscriptionID` relies on `time.Now().UnixNano()` for uniqueness. On macOS and other coarse-resolution clocks, consecutive calls in a tight loop return the same timestamp, so two subscription IDs collide. This is visible as a persistent failure of `TestSubscriptionID_UniqueIDs` (`comm/subID_test.go:32`) on local runs and any CI image with a lower-resolution monotonic clock.
Swap the nanosecond timestamp for a process-local `atomic.Uint64` counter. Monotonic, lock-free, and immune to clock resolution.
Why not UUIDs?
The identifier segment is an opaque string to every consumer (`Unwrap` splits on `-` and returns `subIDParts[2]` as a string without parsing). A counter keeps the existing format, stays compact, and needs no new dep.
Test plan
Notes