Detect the input characteristic instead of hard-coding it (v1.2.4)

[mlstr0m]

Fixes #15.

The bug

The reporter's Switch 2 Pro Controller (bought in Australia) is found and connects, then every attempt dies in start_notify:

bleak.exc.BleakCharacteristicNotFoundError: Characteristic 7492866c-ec3e-4619-8258-32755ffcc0f9 was not found!

That UUID was hard-coded, so any revision that renumbers it was unusable. The log also showed each failure twice, because the teardown called stop_notify for a subscription that had never succeeded.

The fix

The input-report characteristic is now resolved at connect time:

1. the UUID pinned in mappings.json (ble.input_char), if the device actually exposes it;
2. otherwise the documented …f9;
3. otherwise probe the remaining notifiable characteristics — same Nintendo vendor block first, other vendor UUIDs next, SIG-assigned ones (battery, device info) last, capped at 8 candidates.

A candidate is adopted only after it streams a report of at least MIN_REPORT_LEN (11) bytes, i.e. something the parser can actually decode — a 1-byte battery-level notification can't win. The adopted UUID is written back to mappings.json, so subsequent connects skip probing entirely.

Because some firmwares may only report on change, the menubar notice asks the user to move the sticks while identification runs, and the give-up message says the same before pointing at the log.

Also in here:

• full GATT table logged on every connect (GATT: N characteristic(s): …) — this is exactly the information Switch 2 Pro Controller is not recognised #15 was missing to be diagnosable;
• stop_notify is only attempted for a subscription that succeeded;
• the mappings.json write-back is factored into _persist(), shared by the DSU toggle and the new ble.input_char.

Tests

19 new checks in tests/test_bridge.py against a fabricated GATT table: known UUID used without probing, pinned UUID honoured, stale pin falling back, renumbered characteristic adopted and persisted, short (battery-like) reports rejected, probe ordering, non-notifiable characteristics skipped, empty GATT, session failing cleanly with no stray stop_notify, plus ble.input_char parsing and persistence.

python tests/test_bridge.py && python tests/test_dsu.py

Both suites pass locally.

Caveat

If that controller exposes no notifiable characteristic streaming ≥ 11-byte reports at all — for instance if its vendor service only appears after an encrypted pairing — the probe will fail too. In that case the new GATT: log line tells us exactly what the device does expose, which is the follow-up.

🤖 Generated with Claude Code