dart_monty_core 0.18.1

Sandboxed Python scripting for Dart. Low-level binding for pydantic/monty's interpreter.

Changelog

0.18.1

Added

• open() / file I/O. memoryMountedOsHandler now services the Open OS-call (existence-check for r/rb, truncate-create for w/wb, create-preserving for a/ab) and the append_text/append_bytes calls the interpreter emits. Python can open() files, read/write/append, and use with open(...) as f: against an in-memory mount. A new MontyFileHandle MontyValue represents the returned file object.
• resolveOpenCall(...) — the store-agnostic open() primitive that owns the mode→effect mapping (existence-check / truncate / create → file handle, with typed errors). memoryMountedOsHandler delegates to it, and any OsCallHandler (e.g. a package:file-backed one) can support open() by supplying its exists/truncate/createIfMissing primitives.
• Typed OS exceptions. OS-handler errors are now delivered to Python as their real class — except FileNotFoundError: / PermissionError: etc. work. Previously every OsCallException surfaced as RuntimeError (REPL/run path). New FFI + WASM resume entry points: monty_repl_resume_with_exception and DartMontyBridge.replResumeWithException.

Fixed

• memoryMountedOsHandler's Path.read_bytes now returns a typed bytes value instead of a bare list, so binary open(..., 'rb').read() buffers correctly.

Changed

• Snapshot bytecode format (monty 0.18, breaking). The upgrade changed monty's instruction encoding: the monty_snapshot byte stream for "2 + 2" shrank from 74 to 60 bytes. Snapshots are NOT portable across the 0.17 → 0.18 upgrade — consumers persisting snapshots across versions must regenerate them. Pinned by snapshot_format_pinning in native/tests/integration.rs.

Known limitations

• with__cm_* use monty's synthetic _test_cm(), which only exists under the testing-only test-hooks cargo feature (never shipped). They have dedicated conformance on both backends via opt-in test-hooks builds that never touch the shipped binaries: bash tool/test_cm.sh (FFI — marker-gated oracle + dylib) and bash tool/test_cm_wasm.sh (WASM — a staged test-hooks .wasm with the corpus runner compiled -DMONTY_TEST_HOOKS=true). The default suites skip them. Real with open(...) is covered by with__all.
• range__ops exercises 2**63 range membership where the shared monty wasm32 engine diverges from native; skipped on the WASM runners only.
• edge__int_float_mod (int % float) should yield a float; native FFI returns 2.0 but the monty wasm32 engine returns 2 (an upstream wasm number-coercion divergence). Skipped on the WASM runners only; the reverse edge__float_int_mod is unaffected.
• open__fs / open__fs_windows and pyobject__cycle_* pass on both backends.

0.18.0

Tracks upstream monty v0.0.18.

Changed

• Upgraded the embedded interpreter to monty v0.0.18. Headline upstream additions: an open() builtin with buffered file I/O and with / context-manager support, plus a large batch of garbage-collector, exception-safety, and performance fixes.
• resolveFutures per-call errors are now catchable in Python. An errors entry on resolveFutures is raised as a RuntimeError at the await point, so a wrapping try/except RuntimeError catches it normally. Previously this short-circuited past Python's exception handling and terminated the script with MontyScriptError. Scripts that relied on the old script-terminating behavior (without a try/except) still surface a terminal error.

Build

• Building from source now requires Rust 1.95+ (upstream monty v0.0.18 raised its MSRV). Run rustup update stable.

Known limitations

Some v0.0.18 interpreter features are not yet surfaced through this binding. Their corpus fixtures are skipped in the WASM runners (and pass the oracle suite only because FFI and the oracle binary agree on the same gap):

• open() / file I/O — the new Open OS-call is not yet dispatched through the Dart OS handler + WASM VFS (open__fs, open__fs_windows, with__all).
• with context-manager edge cases driven by the test-hooks-only _test_cm() synthetic CM (with__cm_*) — not built into the shipped crate.
• Cyclic-container result comparison in the WASM fixture runner (pyobject__cycle_*); FFI returns the correct cyclic value.
• range__ops — dart2js divergence on 2**63-scale range membership.

Internal

• Adapted the native shim to v0.0.18's restructured OsCall (function / args / kwargs fields replaced by a typed function_call projected via take_function_call().to_args()) and added a JSON mapping for the new MontyObject::FileHandle variant. The new file-handle value currently decodes on the Dart side as a generic MontyDict (__type: "filehandle"); a dedicated MontyValue subtype is a follow-up.

0.17.1

Breaking

• MontyCallback is now (List<Object?> args, Map<String, Object?>? kwargs). Positional args by index (args[0]…); keyword args in kwargs. Old single-map form (args['_0']) no longer compiles.
• .arguments renamed to .args on MontyPending, MontyOsCall, CoreProgressResult, and WasmProgressResult.
• useFutures removed from feedRun/feedStart/Monty.run. Use externalAsyncFunctions instead.

Added

• inputs: on Monty.run/feedRun/feedStart — inject Dart values as Python variables for one execution.
• externalAsyncFunctions — callbacks dispatched via resumeAsFuture; Python can await them and asyncio.gather runs them concurrently.
• MontyInternalError — new MontyError subtype for interpreter-internal failures.
• MontyNone literal — feedRun('None') now returns MontyNone.

0.17.0

Re-cut release: align versioning with dart_monty. Supersedes the retracted 0.0.17 (which omitted native/src/bin/oracle.rs from the published archive, breaking the build hook for consumers).

0.0.17

Initial release.