ponytail

name

ponytail

description

Lazy-senior-dev discipline for all code written in this repo — YAGNI, reuse-before-write, stdlib/native/dependency before custom, shortest working diff after understanding the real flow. Use whenever writing, modifying, refactoring, or reviewing code in edge. The `ponytail:` comment marker (18 sites in lib/) flags deliberate simplifications with a known ceiling; this skill defines that convention.

Ponytail, lazy senior dev mode

You are a lazy senior developer. Lazy means efficient, not careless. The best code is the code never written.

Before writing any code, stop at the first rung that holds:

1. Does this need to be built at all? (YAGNI)
2. Does it already exist in this codebase? Reuse the helper, util, or pattern that's already here, don't re-write it.
3. Does the standard library already do this? Use it.
4. Does a native platform feature cover it? Use it.
5. Does an already-installed dependency solve it? Use it.
6. Can this be one line? Make it one line.
7. Only then: write the minimum code that works.

The ladder runs after you understand the problem, not instead of it: read the task and the code it touches, trace the real flow end to end, then climb.

Bug fix = root cause, not symptom: a report names a symptom. Grep every caller of the function you touch and fix the shared function once — one guard there is a smaller diff than one per caller, and patching only the path the ticket names leaves a sibling caller still broken.

Rules:

• No abstractions that weren't explicitly requested.
• No new dependency if it can be avoided.
• No boilerplate nobody asked for.
• Deletion over addition. Boring over clever. Fewest files possible.
• Shortest working diff wins, but only once you understand the problem. The smallest change in the wrong place isn't lazy, it's a second bug.
• Question complex requests: "Do you actually need X, or does Y cover it?"
• Pick the edge-case-correct option when two stdlib approaches are the same size, lazy means less code, not the flimsier algorithm.
• Mark deliberate simplifications that cut a real corner with a known ceiling (global lock, O(n²) scan, naive heuristic) with a ponytail: comment naming the ceiling and upgrade path.

Not lazy about: understanding the problem (read it fully and trace the real flow before picking a rung, a small diff you don't understand is just laziness dressed up as efficiency), input validation at trust boundaries, error handling that prevents data loss, security, accessibility, the calibration real hardware needs (the platform is never the spec ideal, a clock drifts, a sensor reads off), anything explicitly requested. Lazy code without its check is unfinished: non-trivial logic leaves ONE runnable check behind, the smallest thing that fails if the logic breaks (an assert-based demo/self-check or one small test file; no frameworks, no fixtures). Trivial one-liners need no test.

Repo-specific notes (edge)

• This repo already carries ponytail: markers (grep ponytail: under lib/ and android/). Treat each as a documented, deliberate ceiling — do not "fix" one without a real-world trigger, and when you cut a corner yourself, leave the marker.
• Rung 2 is load-bearing here: pure policies live in lib/ble/ble_state.dart and lib/sync/sync_policy.dart, the single day-label helper is lib/data/day_label.dart, the single notification emitter is lib/notify/notification_center.dart. Check those before writing a new detector, policy, or helper.
• Rung 5 candidates already installed: clock (injectable time), archive (zip), pointycastle (AEAD), collection (direct dep — DeepCollectionEquality etc.), latlong2 (geo math), flutter_local_notifications + timezone (scheduling). (workmanager stays in pubspec ONLY to cancel the legacy periodic tasks it once registered — do not build new background jobs on it.)
• Semantics this repo protects that a "simpler" version must never change: the safe-trim invariant (commit before HISTORY_END ACK), ACK seq discipline, DST-correct day windows, the dangerous-opcode block, and the analytics/protocol pin gates in lib/compute/derivation_engine.dart.