wasi-fixtures

name	wasi-fixtures
description	Add or update WASI preview1/wasip2 fixture smokes, regenerate catalogs, and run coverage runtime gates. Use when working on fixtures/wasip1, fixtures/wasip2, smoke_templates, generate_fixtures, or RUNTIME_EXCEPTIONS.

WASI fixture maintenance (Ark)

Layout

Path	Role
fixtures/wasip1/	Preview1 runtime fixtures (tests/wasip1_spec/generate_fixtures.py)
fixtures/wasip2/runtime/	Component runtime smokes (tier=runtime)
fixtures/wasip2/compile_only/	Import ABI stubs + blocked cases
tests/wasip2_spec/smoke_templates.py	Runtime smoke bodies + RUNTIME_EXCEPTIONS
tests/wasip2_spec/wasip2_sig.py	Canonical import signatures for codegen
tests/wasip2_spec/runtime_exceptions.txt	Human-readable blocked list (doc)

Regenerate

python3 tests/wasip2_spec/generate_fixtures.py
python3 tests/wasip1_spec/generate_fixtures.py   # if wasip1 touched
python3 scripts/gen_fixture_remediation_doc.py

Catalogs updated: tests/wasip2_spec/{functions,runtime,compile_only}.catalog.

Gates (native)

moon test -p coverage --target native --filter "wasip1 runtime fixture execution"
moon test -p coverage --target native --filter "wasip2 native command runtime fixture wasmtime execution"
moon test -p coverage --target native --filter "wasip2 native command compile_only compile and WIT import ABI"
moon test -p cmd/ark --target native --filter "wasip2 compat"

Adding a wasip2 runtime smoke

1. Implement render_wasip2_smoke() branch or helper in smoke_templates.py.
2. If the import cannot run under component-wasi02-command + wasmtime, add (wit_iface, field) to RUNTIME_EXCEPTIONS and document in runtime_exceptions.txt.
3. Regenerate fixtures; run both wasip2 gates above.
4. moon info && moon fmt in touched MoonBit packages.

Patterns that work

• Stdout marker: expect_guest_stdout=tag: + blocking_write_and_flush(get_stdout(), ...).
• Sockets: create_*_socket(0, 256) → handle at load_i32(260); start-bind / start-connect use address args 0, 128, 16 (not p0=128).
• TCP/UDP lifecycle methods: listed in _SOCKET_RUNTIME_ALLOW (finish-bind, start-bind, local-address, etc.).
• Wall clock now: import alias wall_clock_now — now is an Ark keyword; tag-only smoke (datetime bytes OK on resolution via write_datetime_bytes).
• Monotonic subscribe: drop(subscribe_instant(0)) / subscribe_duration(0) + tag stdout.

Permanently blocked (keep compile_only)

Area	Reason
wasi:http/types ctors/static	wasmtime missing http resource linker
wasi:http/outgoing-handler handle	live HTTP / proxy
resolve-addresses, resolve-address-stream	CI network + invalid handles
UDP datagram-stream receive/send/subscribe	invalid handle / ABI mismatch
get-random-bytes, get-insecure-random-bytes	list-u8 return ABI vs guest len, buf stub
poll	guest list ABI vs component typecheck (list<borrow<pollable>> lowering)
filesystem-error-code, error.to-debug-string	borrow handle 0 invalid at runtime
wasi:cli/exit	runtime smoke writes exit:42 then calls exit(0) (wasmtime does not surface guest status 42)
wasi:clocks/timezone@0.2.0	not in command world (experimental compile_only only)

HTTP bulk (~50 compile_only)

Do not delete RUNTIME_EXCEPTIONS entries for http types until linker resources exist in the component pipeline. Optional future work: narrow http-proxy world in compile/component_build.mbt + coverage gate.

Target isolation gates

coverage/gate.mbt rejects cross-target WASI imports in compiled wasm:

• wasip1: check_no_wasip2_import_modules — no wasi: WIT module names in preview1 fixtures.
• wasm2: check_no_wasi_import_modules — no wasi* import modules in core wasm2 fixtures.

Do not repeat

• http ctors without linker resources
• UDP receive hang / datagram streams without lifecycle fix
• resolve-address-stream with dummy handle 20
• start-bind with p0=128 (use p0=0, p1=128, p2=16)