v1.5.0-beta.0

Prerelease. This is the first public beta of v1.5.0. Installed via npm install @mjayb/sonicpijs@beta; the default latest tag still points to v1.4.0. Bug reports welcome on GitHub issues — the in-app Report Bug button pre-fills the version, browser, and current code.

Engine audit — 33 bugs fixed

Found during a multi-round audit against MagPi book chapters, official Sonic Pi wizard/sorcerer/magician examples, and community forum compositions. Per-bug rationale in the engine audit PR (#155) and synth alias cleanup (#157).

Critical engine:

• randomSuffix() was const f = (): string => f() — infinite recursion on top-level in_thread/at
• ProgramBuilder children (in_thread/with_fx/at) not inheriting _transpose, _synthDefaults, _sampleDefaults
• wrapBareCode didn't track loop do/.times do/.each do — use_synth hoisted out of loops
• normalizeSampleParams missing expandSlideParam — sample :x, slide: silently ignored
• normalizeFxParams resolved symbols AFTER injecting defaults (wrong order)
• with_bpm didn't restore previous BPM
• resumeTick() race condition on rapid pause/resume

Bridge / runtime:

• in_thread inside with_fx not inheriting outBus — thread audio bypassed FX entirely
• Sample/SynthDef lazy-load race conditions (buffer leaks, duplicate loads)
• freeBus() allowed duplicate frees — bus collision
• fetchSampleDuration silently swallowed errors, breaking beat_stretch

DSL / tutorial parity:

• use_sample_bpm — wrapper around use_bpm(60 / sample_duration(name))
• midi shorthand — midi 60, sustain: 0.5 (note_on + auto note_off)
• use_osc / osc shorthand — state variable for default host/port
• with_fx reps: — FX body now loops N times within same FX instance
• with_synth_defaults / with_sample_defaults — scoped variants
• use_density — permanent density setter
• use_debug — exposed in sandbox as no-op (was causing crashes)
• .take(n) — transpiler was emitting .slice() but Ring uses .take()
• Ring.line(steps=1) returned [NaN] (division by zero) — now returns [start]

Public API additions:

• Exported: hzToMidi, chord_degree, degree, knit, range, line

Sandbox fixes:

• get() was defined as a new Proxy(...) not a function — get(:key) crashed
• with_random_seed, with_octave, with_density, with_synth_defaults, with_sample_defaults weren't in transpileWithBlock handler — blocks transpiled without callback wrapper
• TOP_LEVEL_SETTINGS missing use_arg_bpm_scaling

Architectural fix — b shadowing:

• User variable b shadowed ProgramBuilder callback parameter via Proxy set trap. Renamed internal parameter from b to __b across all transpiler output sites (callback params, method prefixes, __checkBudget, stop, lastRef, density, define funcs, at callbacks). Documented in KNOWN_LIMITATIONS.

wrapBareCode regex expansion:

• Regex only matched /^\s*(play|sleep|sample)\s/ — missed play_chord, play_pattern_timed, use_synth_defaults, synth, control, cue, sync, etc. Expanded to cover all bare DSL callables that need __b scope.

Synth aliases:

• Removed dark_sea_horn and singer from SYNTH_NAMES — no corresponding .scsyndef on the SuperSonic CDN (silent failure trap).

Verified compatibility

56 real-world compositions run end-to-end in Chromium capture:

• 18 E2E tests (covering 122 DSL functions)
• 7 MagPi Essentials chapter examples
• 15 official Sonic Pi examples (wizard/sorcerer/magician tiers from etc/examples/)
• 13 community forum compositions from in-thread.sonic-pi.net
• 3 edge cases

Test coverage

• 703 unit tests pass
• Zero TypeScript errors

UI

• Version label in the menu bar displays v1.5.0-beta.0 (top-right, muted). Click to copy the full SonicPi.js v1.5.0-beta.0 string to clipboard. Pre-filled into the Report Bug URL so every bug report is tagged to a specific build.

Release engineering

• This is the first release following the new release-cycle criteria: single version string across all surfaces, npm --tag beta to protect latest, UI footer as the load-bearing signal for the prerelease channel, explicit beta → RC → stable gate criteria documented in the release runbook.

Known limitations

See KNOWN_LIMITATIONS.md for the current list. The limitations file is the single source of truth; it is intentionally NOT duplicated per-release in this changelog. Noteworthy feasible-but-not-built items tracked for post-beta work: external sample upload (#159), OSC receive via WebSocket bridge (#150), synth :sound_in via getUserMedia (#152), use_real_time MIDI latency bypass (#149), .zip/.each_with_index Array methods (#154).

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