v0.0.19 - 2026-07-24

What's Changed

• introduce iterator helpers that manage recursion / time by @davidhewitt in #454
• fix interactions with global names, function scopes & repl by @davidhewitt in #469
• experiment with StringBuilder to guard strings under construction by @davidhewitt in #448
• fix type-object marshalling across the sandbox boundary by @samuelcolvin in #478
• FromArgs slots cleanup by @samuelcolvin in #484
• fix(file): release the buffered-file OS-call pin on all paths by @arkuhn in #485
• add __name__ et al. by @samuelcolvin in #495
• f-strings improvements by @samuelcolvin in #494
• fix: return error instead of panicking in ForIter heap read by @tontinton in #493
• Move execution to a subprocess pool by @samuelcolvin in #500
• Add 'Part of the Pydantic Stack' footer to README by @strawgate in #502
• fix(asyncio): raise RuntimeError on cross-gather coroutine reuse by @samuelcolvin in #503
• fix CI since subprocesses by @samuelcolvin in #505
• Async memory limits by @samuelcolvin in #504
• uprev ruff and ty crates by @samuelcolvin in #506
• move py_eq to accept &Value for RHS by @davidhewitt in #508
• use published ruff and ty crates by @samuelcolvin in #512
• reintroduce feed_start API to both python & JS by @davidhewitt in #507
• use stable clippy in ci by @samuelcolvin in #513
• Publish all library crates to crates.io by @samuelcolvin in #514
• websocket protocol by @samuelcolvin in #509
• Support multi-level (transitive) closure capture by @samuelcolvin in #516
• move recursion count from heap to VM by @davidhewitt in #511
• monty-cpython: rich sandbox tracebacks with source previews and carets by @samuelcolvin in #517
• fix various bugs with global name scoping by @davidhewitt in #510
• ci: try newer manylinux version by @davidhewitt in #519
• Add unicodedata module, refactor and improve FromArgs macros by @samuelcolvin in #522
• rename and change behaviour of external_lookup by @samuelcolvin in #520
• encode and decode codecs and error types by @samuelcolvin in #523
• Fix wasm CI by @samuelcolvin in #526
• Add resume_auto() to iteratively drive feed_start snapshots by @samuelcolvin in #527
• User-defined classes by @samuelcolvin in #515
• small perf wins by @samuelcolvin in #528
• Add benchmarks covering real agent workloads by @samuelcolvin in #530
• Bound native evaluate_function re-entry to prevent infinite recursion by @samuelcolvin in #529
• Restrict git commit and git push for claude by @samuelcolvin in #532
• Regex perf improvements by @samuelcolvin in #531
• String cheap wins (perf track 3) by @samuelcolvin in #537
• add ci stage for browser testing by @davidhewitt in #539
• prep for beta release by @samuelcolvin in #540
• Fixing CI for0.0.19-beta.2 by @samuelcolvin in #542
• merge DropWithHeap / DropWithVM by @davidhewitt in #521
• fix interned longint ops by @davidhewitt in #547
• Add per-crate READMEs, rename monty-cli to monty-runtime by @samuelcolvin in #544
• migrate from ava to vitest by @davidhewitt in #548
• use web workers for browser wasm by @davidhewitt in #525
• remove cargo config by @davidhewitt in #546
• Monty-proto moves by @samuelcolvin in #549
• JSON error data, and type conversion to cpython by @samuelcolvin in #552
• Prep for 0.0.19-beta.3 by @samuelcolvin in #555
• monty-wasm-runtime publish false, prep 0.0.19-beta.4 by @samuelcolvin in #559
• clean up js packaging / smoke test by @davidhewitt in #550
• build and release the monty-cpython container by @samuelcolvin in #563
• remove mod eq optimization by @davidhewitt in #565
• Add pytest-style assert failure messages by @samuelcolvin in #556
• remove monty-cpython by @samuelcolvin in #571
• improve error messages from suspensions in evaluate_function by @davidhewitt in #573
• inline clone_immediate into clone_with_heap by @davidhewitt in #578
• Make an existing iterator self-iterable by @rewitt94 in #579
• Move mounting to the host-side and move fs to monty-fs by @samuelcolvin in #576
• Arg fixes, int(), str(), round() by @samuelcolvin in #584
• Public API fixes by @samuelcolvin in #587
• add iterator to PyTrait by @davidhewitt in #575
• Support class decorators by @rewitt94 in #582
• Implement iter(callable, sentinel) by @rewitt94 in #581
• Retain the OS-call payload in suspended state and drop OsFunctionCall::Used by @samuelcolvin in #583
• avoid collisions in id by @davidhewitt in #580
• migrate iterator callsites to py_iter by @davidhewitt in #588
• stop uninstalling workspace in make install-py by @davidhewitt in #595
• use web-time for the resource-tracker clock so max_duration works on wasm32-unknown-unknown by @Butch78 in #554
• Allow any iterable after *, not just five container types by @rewitt94 in #589
• monty-types crate by @samuelcolvin in #592
• Teach the type checker about iter/next by @rewitt94 in #596
• Bump version to 0.0.19-beta.5 by @samuelcolvin in #597
• fix npm publish by @davidhewitt in #603
• Fix leaks and panics on MontyObject conversion error paths by @samuelcolvin in #600
• release 0.0.19b6 by @davidhewitt in #604
• make dev-py install python dev deps by @davidhewitt in #606
• Cap CollectString/CollectStreams so print loops can't OOM the host by @Shaurya-Sethi in #558
• Remove ResourceError::Exception and fix check_replace_size shrinking bypass by @samuelcolvin in #610
• Remove max_allocations from resource limits by @samuelcolvin in #611
• Reject action-less open modes, fix mixed-indent traceback dedent by @samuelcolvin in #612
• use same build profile for codspeed as release by @samuelcolvin in #614
• Prep for v0.0.19 by @samuelcolvin in #616

New Contributors

• @arkuhn made their first contribution in #485
• @tontinton made their first contribution in #493
• @strawgate made their first contribution in #502
• @rewitt94 made their first contribution in #579
• @Shaurya-Sethi made their first contribution in #558

Full Changelog: v0.0.18...v0.0.19