fix: crash bugs in community apps

[Swissola]

Summary

Six crash fixes across five community apps, found during code review. All are edge cases with no impact on normal operation.

Connect — malformed HTTP request line (Connect.py)

request_line.split() is unpacked directly into three variables. A malformed or empty request line (fewer than 3 tokens) raises ValueError. Added a len(parts) < 3 guard with continue before unpacking.

LowPowerClock — path_list IndexError (powermanager.py)

path_list[1] is accessed before checking its length. When __name__ contains no . (single-component module path), split('/') produces a one-element list and path_list[1] raises IndexError. Added len(path_list) > 1 guard.

timer — empty string IndexError after lstrip (timer.py)

time_value.lstrip("0") is called, then time_value[0] is checked. If the value was "0" (all zeros), lstrip produces "" and [0] raises IndexError. Added a truthiness guard: if time_value and time_value[0] == ".".

RandomScale — ZeroDivisionError + sample accumulation bug (Audio.py)

Two bugs in generateTriangleWave():

1. When freq == 0, 1/freq and the math.sin call both raise ZeroDivisionError. Added early return with empty bytearray.
2. sampleList = bytearray((sample, sample)) overwrites the list on every iteration instead of appending. Changed to sampleList += bytearray(...) so samples actually accumulate.

mmlPlay — ZeroDivisionError + octave IndexError (mmlPlay.py)

1. generate_square_wave() divides by frequency; rests/silence notes with frequency 0 crash. Guard returns a silent buffer early.
2. get_note_frequency() indexes FREQ_TABLE[note][octave] with no bounds check. An out-of-range octave value (from malformed MML or edge-case parsing) raises IndexError. Clamped to 0..len(FREQ_TABLE['C'])-1.

KanjiReader — bare file seek/read (KanjiReader.py)

fn.seek(idx) and fn.read(100) can raise OSError if the file is on SD card and the card is removed or the file handle is stale. Wrapped in try/except OSError that returns the current position so the caller can continue gracefully.

Test plan

• Connect: send a raw TCP connection with a blank line — no crash
• LowPowerClock: run app installed directly (no subdirectory) — no crash in store()
• timer: type 000 and delete until display shows 0 — no crash
• RandomScale: trigger a note with frequency 0 — silent, no crash
• mmlPlay: play MML with a rest (R) note — no crash; play with extreme octave value — no crash
• KanjiReader: remove SD mid-read — graceful skip, no crash

🤖 Generated with Claude Code