A constructor-function stream now reads `_final` and `_flush` when its
writable side finishes, and `_transform` for each chunk, as Node does. A hook
assigned after `Writable.call(this)` or `Transform.call(this)` runs, and an
override of a PassThrough's `_transform` replaces the pass-through. Without
`_final` or `_flush` the finish continues as Node's does.
A runtime stream passed to a constructor-function stream's listeners, such
as the source of a 'pipe' event, is the view whose pipe and unpipe accept
constructor-function streams, so `src.unpipe(this)` in a 'pipe' listener
unpipes instead of throwing.
The backend can emit scr_wasm_memory_construct, scr_wasm_table_construct,
scr_wasm_global_construct, scr_wasm_construct_without_new,
scr_wasm_module_imports, scr_wasm_module_exports,
scr_wasm_module_custom_sections and scr_wasm_value_of (#1410), and
scr_stream_dyn_native, scr_stream_pipe_dyn and scr_stream_unpipe_dyn
(#1524). Their prototypes were in scr_wasm.c or nowhere, so the runtime
ABI guard failed. They are now in scr_wasm.h and scr_stream.h, and
scr_wasm.c no longer repeats the header's declarations.
The speculative-hoisting test relied on `v instanceof Num` in a
JavaScript function failing, which constructor-function instanceof now
compiles (#1512). Its hoisted function reads the prototype through
Reflect.getPrototypeOf instead, which still fences.
With checked-dynamic stream slots, readable.unpipe() also unpipes every
JavaScript destination stream.pipeDyn registered from the source, oldest
pipe first. Each destination hears 'unpipe' and the source pauses, as in
Node's unpipe(), which empties every pipe. Before, those pipes stayed
attached and later chunks still reached them.
pipe() into an untyped destination now comes from main's pipeIntoDyn
(stream.unboxDyn); programs with constructor-function streams unbox
through scr_dyn_builtin_stream.c, which also takes those streams, so the
separate dyn.builtinStreamPipe entry point is gone.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Bundled npm code (from2, bl, tar-stream, yazl, multistream) builds its
streams as ES5 constructor functions: util.inherits(Ctor, Readable) and
Readable.call(this, opts), with _read/_write/_transform on the
prototype. Readable.call(this) threw SC2020.
A new runtime unit, scr_dyn_builtin_stream.c (feature
dynBuiltinStream), gives the untyped stream constructors their stream
half. Base.call(this, opts) creates a runtime stream over the receiver
and keeps it in a hidden slot; the runtime calls the receiver's
underscore methods through its property lookup; the stream prototypes
carry Node's methods and accessors over the hidden stream; and
EventEmitter's methods register listeners with the runtime stream's
emitter, so runtime events and pipes reach JavaScript listeners with the
receiver as this. _readableState/_writableState are live views.
Stream class values now come from dyn.builtinStreamClass, so only
programs that use them link the stream half. Typed code sees these
objects as their runtime streams: checked casts to the stream classes
take them, readable.pipe() into an untyped destination pipes into them,
and runtime streams crossing into JavaScript answer the constructor
object.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
readMemargFlags took its reader as a `{ u32(): number }` record, and the
validator (Reader) and translator (WasmCursor) pass class instances. The
self-hosted compiler refuses a class instance in a record-typed parameter
(SC2002), so the self-hosted LLVM emitter, the native frontend programs
and the bootstrap seed builds failed. readMemargFlags now takes the
reader's u32 function, and each caller passes `() => r.u32()`.
Object.fromEntries(...) as T passed the entries through the
checked-dynamic bridge, which copies native arrays and records: an array
shared by two entries, or held elsewhere, became separate copies, and
writes through the asserted object no longer reached it. The bridge now
applies only when the entries' values are scalars or checked-dynamic
values, which pass by value or by identity; other entries keep the
exact-shape fence (SC2002). Corpus 6467 checks that entries held as
unknown keep their identity; diagnostics fixture
fromentries-aliased-entries.ts pins the fence.
The bakeability check tracks the unions it is inside as well as the
records, so a union reachable from itself through an array
(`type Tree = number | Tree[]`) reports SC1090 instead of recursing without
end. The message names both recursive records and recursive unions.
- Merge origin/main (e9fb01603); the import lines at the top of
lowerer.ts conflicted and both are kept.
- Corpus 6385 gains a wrapper whose block-local `args` alias shadows an
outer one in the same function; each call forwards its own arguments.
- EventEmitter.defaultMaxListeners on the untyped constructor is Node's
accessor over the default the typed EventEmitter reads: assignments
validate as validateNumber(arg, 'defaultMaxListeners', 0) does, and
getMaxListeners() of emitters without their own limit answers the new
value.
- dyn.builtinInstanceOf and dyn.functionInstanceOf link the
constructor-function unit and the units it calls (dyn-invoke, inspect,
symbol, emitter), so a program whose only use is `this instanceof F`
links.
- The legacy pipe's cleanup runs once: when the destination emits
'close' from end(), the cleanup still queued on the source's 'end'
finds the listeners removed and emit('end') answers true.
pipe() called from untyped JavaScript on a native stream went through
scr_stream_pipe directly, so a helper that piped into the converted
process.stdout or process.stderr ended it at the source's end, and later
writes through the program's NodeJS.WritableStream slots failed. The
stream view's pipe now calls scr_stream_pipe_general, which keeps end off
for those Writables, as Node's pipe() does for process.stdout and
process.stderr.
Adds corpus 6469.
A method call declared to return `this`, such as setEncoding, resolves to
its receiver's access path, so a 'data' listener on the stream that
`const out = child.stdout.setEncoding("utf8")` returns receives strings.
A setEncoding call that a preceding statement always evaluates (its
expression, a variable initializer, or the receiver of a method chain in
one of those) counts as preceding the listener. Only `new` and the
child_process factories (spawn, fork, exec, execFile) count as creating a
separate stream; any other call result may be a stream another binding
already holds.
Externrefs a guest holds are borrowed pointers. An import's result was
kept only until the outermost call returned, which was before the export
call converted its results to JavaScript, so a result created by an
import was freed before conversion. A table or global slot released the
reference it replaced at once, although the guest may still hold it in a
local after reading the slot. The kept references are now released after
the outermost caller has converted its results (scr_wasm_leave), and a
table or global store during a call keeps the reference it replaces until
then.
Checked memories (explicit bounds checks: sanitized builds, Windows)
grew with realloc, which can move the storage that memory.buffer and its
views alias. They now reserve the address space for their largest size
(mmap on POSIX hosts, VirtualAlloc on Windows) and commit pages as they
grow, so the base never moves. Hosts without address-space reservation
grow in place only until a buffer has been handed out; after that,
growth that would move the storage fails.
Tests: webassembly-externref-lifetimes.mjs (import results through an
export, table and global references replaced by the guest and by
JavaScript), webassembly-memory-growth.test.ts (views written after
growth from JavaScript and from the guest), and translate.test.ts cases
for memargs naming memory 0 explicitly and for local.tee operand types,
which b3bcbaaf7 made consistent with validation. Under SCRIPTC_SAN=1 the
two runtime tests report heap-use-after-free without these changes.
Merges main; internal/compatibility/generated/node-v24-backlog.json is
regenerated with pnpm node-compat.
6490 covers events.once with an AbortSignal: abort, an aborted signal, an
undefined signal, abort-listener order, 'removeListener' events, a
throwing 'newListener' listener and the settlement turns. 6491 covers
stream receivers (file streams, Readable.from, a destroyed PassThrough, a
Writable) and a NodeJS.ReadableStream part raced against its destination.
6492 covers races over events.once results with entries that only reject
and entries of different value types. 6493 covers stream subclasses whose
completion callbacks are typed `Function`. 6494 covers events.once over
checked-dynamic stream slots. The node-types fixture runs the race shapes
under @types/node, where events.once returns Promise<any[]>.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The fallback declaration of events.once takes NodeJS.ReadableStream and
NodeJS.WritableStream emitters like @types/node does. The diagnostics
fixture now pins the forms that stay refused (options that are not an
object literal, a computed name, a stream's 'data' event), and the
limitations page states the supported events.once forms.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Under checked-dynamic NodeJS stream slots, events.once over a
NodeJS.ReadableStream or NodeJS.WritableStream slot unboxes a native
stream by identity and takes the stream path; any other value throws the
not-supported Error that for await and pipeline stages already throw for
JavaScript stream objects.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A stream subclass that declares `_transform(chunk, encoding, cb: Function)`
(or _write, _final, _destroy, _flush with a broad `Function` callback) was
rejected because 'Function' has no lowering, which also blocked every
construction of the class. The callback parameter now takes the
checked-dynamic callable the runtime already passes implicitly typed
callbacks, and calls through it are dynamic calls.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
When the checker's combined type has no representation (events.once's
any[] arrays, or 'void | any[]'), the race result takes the one type the
entries that can fulfill share, or 'unknown' when each of them widens into
it; Promise<never> entries do not take part. An entry whose payload widens
into the result type converts through the checked promise payload
widening, which keeps its settlement turn.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The Promise.race portion of 465abda81 on main, applied unchanged so the
race changes that follow build on it and merge with main cleanly: a
Promise<never> entry can only reject, so it races under any result type
and its fulfillment adapter traps; a Promise<never> executor's
one-parameter resolve validates against the void inner. Includes that
commit's corpus program 6450.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Chris Tate