Fix every type error in test/

[Jarred-Sumner]

What does this PR do?

cd test && bun check (#44361) reported 8,080 type errors in 1,107 files. Now it reports none. tsc 7.0.2 agrees on both numbers.

$ cd test && bun check
✓ No type errors in 2,615 files [418.81ms]

Apart from the few files listed under "The JavaScript that did change", every edit to a test is erased by the transpiler: annotations, type arguments, !, casts, import type, // @ts-expect-error. That is checked mechanically, see below.

test/tsconfig.json

• baseUrl is gone. TypeScript 7 rejects it (TS5102) and stops before checking anything. paths resolve relative to the tsconfig.json without it, in tsc and in Bun's resolver. Of the 1,697 distinct (directory, bare specifier) pairs imported anywhere below test/, .js files included, one resolved through baseUrl: "harness.js" in pnpm-migration.test.ts. It is "harness" now, which is the same file.
• lib.dom is gone. The config says "lib": ["ESNext"], but one unused svelte fixture had /// <reference lib="dom" />, which adds lib.dom to the whole program. With lib.dom loaded, bun-types steps aside for ReadableStream, WebSocket, CompressionStream, fetch and others, so type: "direct" streams, new CompressionStream("zstd"), new WebSocket(url, { headers }) and so on were all errors.
• composite: false, like src/js/tsconfig.json. Tests emit no declarations, and they import files from all over the repository, each of which was a TS6307.
• bun-types comes in through include, like in src/js/tsconfig.json. A types entry is looked up from the directory of the config that extends this one, so bundler/transpiler/tsconfig.json could not find it, and neither could an editor or bun check <file> for a file in that directory.
• Excluded: code vendored from Node.js and the React Compiler, esbuild-decorator-tests.ts (standard decorators, this project sets experimentalDecorators), the bun-types fixture (declares globals such as ProcessEnv.FOO, and bun-types.test.ts checks it with its own config), and six fixture apps that have their own package.json and tsconfig.json and whose dependencies the test installs.
• ../src/runtime/bake/client/**.ts is no longer included. Tests import two of those files, which still brings them in. The rest needs lib.dom and belongs to src/runtime/bake/tsconfig.json.

Two small ambient files are new. test/internal-for-testing.d.ts declares the 9 $ intrinsics that src/js/internal-for-testing.ts calls (src/js/builtins.d.ts and private.d.ts declare them next to changes to Error, Function and other globals that tests should not see). test/asset-imports.d.ts declares *.c, *.cc, *.h, *.pem, *.br and *.gzip, which tests import as a path or as text.

Tests import a few files from outside test/, so those are part of the project: 5 files in packages/bun-error, packages/bun-release and scripts/build got the same kind of erased fix.

bun-types

Correct tests that did not type check because the declarations were wrong. Each has a case in test/integration/bun-types/fixture.

	before
test.todo("label"), describe.todo("label"), and the same for skip	TS2554, fixes #25959. The runtime allows a missing callback for both. Parameters<typeof test.skip> is unchanged, and describe.skip(SomeClass) is still an error: on its own, a function is the body
test("label", { retry: 1 }, () => {})	TS2769. It is the form in docs/test/index.mdx. Parameters<typeof test> is unchanged
test.each(["a", "b"] as const), describe.each(...)	"readonly ... cannot be assigned to the mutable type 'unknown[]'"
expect(await sql`select 1`).toEqual([{ x: 1 }])	"not assignable to parameter of type 'undefined'". For a call that is only generic in its return type, T was inferred as never from expect(actual?: never), so that overload won. Same for webview.evaluate()
Bun.write(path, Bun.TOML.stringify({ ... }))	string | undefined for every input. It is undefined only for undefined, a function or a symbol, and the return type says so now. This was about 350 of the errors
Bun.YAML.parse(buffer)	string only. The runtime takes what Bun.TOML.parse takes: typed arrays, ArrayBuffer, DataView, Blob
new ReadableStream({ type: "bytes" }) without lib.dom	TS2769, and a comment said Mode "bytes" is not supported. The overload is the last one, so a source typed any still gives ReadableStream<any>
new Blob().slice() without lib.dom	TS2339
new TextDecoderStream("utf-16le", { fatal: true }) without lib.dom	TS2554
webview.goBack(), webview.goForward()	declared as back() and forward(), which do not exist at runtime

The JavaScript that did change

For the type check:

• cli/install/migration/pnpm-migration.test.ts: "harness.js" is "harness", see above.
• js/sql/wire-frames.ts declared export function pgParameterStatus twice, with the same body (TS2393). The second one is gone.
• bundler/transpiler/macro-test.test.ts: its three assert { type: "macro" } imports are with { type: "macro" }. In TypeScript 7 assert is a syntax error (TS2880), which // @ts-expect-error cannot suppress and which stops the check of the whole project. The transpiled imports are the same. One test is new: it covers assert for a named, aliased, default and namespace import and for "bun", from a fixture string.
• js/bun/xml/generate_xml_test_suite.ts emits the expect<unknown>(...) that the generated suite now has.
• harness.ts passes toMatchNodeModulesAt, toHaveBins, toBeValidBin and toBeWorkspaceLink to its own expect.extend(). It declares them on Matchers<T> now, which applies to the whole project, so a test that forgot to register them would type check and then fail with "toHaveBins is not a function".
• 6 files in integration/bun-types/fixture have new cases. They are only type checked.

Bugs in tests that a type error pointed at, where the alternative was a cast that hides it. Each was run on main and on this branch:

	on main	now
js/web/fetch/headers.undici.test.ts	14 lines are expect(actual, expected): no matcher, the second argument is the failure message	expect(actual).toBe(expected), all pass
js/node/crypto/crypto.key-objects.test.ts	an expect() without a matcher, publicKey.y compared with itself (2x), 8 assertions after publicKeyFromJwk / privateKeyFromJwk that check the other key, a callback for generateKeyPairSync() that uses undeclared resolve / reject	they assert what they mean to, the callback is gone, same pass count
js/bun/shell/test_builder.ts	import { ShellError } from "bun" is undefined, so .error(aShellError) throws Right hand side of instanceof is not an object. doChecks() is not awaited in the catch path	$.ShellError, awaited. The shell suite gives the same results
js/bun/http/bun-serve-ssl.test.ts	keepAlive: false, which fetch does not read	keepalive
js/bun/websocket/websocket-server-backpressure-buffer.test.ts	maxBackpressure, which Bun.serve does not read, so both tests ran with the default limit	backpressureLimit
bundler/bundler_splitting.test.ts	10 tests pass env: "inline", which is the environment of the subprocess (0=i, 1=n, ...)	dotenv: "inline"
bundler/esbuild/default.test.ts	automaticRuntime: false, which the helper does not read, so the test was a todo	runtime: "classic", passes, not a todo
js/web/fetch/body.test.ts	const { readable } = file(url) is undefined, so the case was skipped as "fails, text is empty"	file(url).stream(), passes, not skipped
js/web/fetch/fetch.test.ts	first[0] on an ArrayBuffer: compares undefined with undefined	Uint8Array views, so it checks that arrayBuffer() returns a copy
js/bun/util/password.test.ts	the async hash helper calls hashSync()	password.hash()
js/node/http/node-http.test.ts	socket => expect(socket).toBe(socket) shadows the socket it means to compare with	compares with the outer one
cli/install/bun-install.test.ts	with --todo, two todo tests fail in their setup: ctx is not defined, and join({ root }, ...)	they reach their assertions. Still todo
js/bun/test/fake-timers/sinonjs/fake-timers.test.ts	let timersModule, timersPromisesModule shadows the two imports (inside describe.todo)	the let is gone
harness.ts	toHaveBins() passes for an empty .bin directory, [].every(...) is true	compares the number of bins. The 56 call sites pass, also on Windows
harness.ts, cli/install/bun-install-registry.test.ts	new Error("Failed to create user:", response.statusText) drops the status text	it is in the message
docker/index.ts	waitTcp() calls Bun.connect() without socket, which throws, so it times out on an open port	resolves in 2 ms, still times out on a closed port
js/bun/archive-extract-leak-repro.ts	Bun.Archive.from() does not exist	new Bun.Archive(), the script runs

With TypeScript 6.0.2

cd test && bun run typecheck goes from 8,065 errors to 2, both TS2786 in jsx-production.tsx and jsx-dev.tsx. TypeScript 6 adds an implicit react/jsx-runtime import to every file of a react-jsx project, also to ../src/js/internal-for-testing.ts, where it resolves to the root's @types/react 18.3 instead of test/'s 18.0. TypeScript 7 only adds it to files that have JSX.

Not in this PR

• Nothing in CI type checks test/, so this can regress. .github/workflows/lint.yml checks scripts, src/js, src and src/runtime/bake.
• bun check at the repository root follows the references in the root tsconfig.json, and src/tsconfig.json, src/js/tsconfig.json and src/runtime/bake/tsconfig.json still have baseUrl.

How did you verify your code works?

• bun check, tsc 7.0.2: 0 errors. tsc 6.0.2: the 2 above.
• Same JavaScript. A script transpiles each changed file at main and on this branch (bun build --no-bundle, so with this tsconfig.json's emitDecoratorMetadata) and compares the output: of 662 files, 634 are byte-identical, 1 differs in the line breaks of an object literal that prettier re-wrapped (identical with --minify-whitespace), and 27 are the ones listed above.
• Same test results. Line numbers, columns and file sizes do change, and some tests look at their own (response.test.ts snapshots Response (8.0 KB) for its own source file). So I ran the 1,322 test files that changed or that sit next to a changed helper or fixture, on main and on this branch, with the same release build (linux x64, no docker): 49,644 tests pass on main. 1,302 files have the same exit code, the same pass / fail / skip / todo counts and the same failing tests. The other 20 differ in both directions (11 better, 9 worse). Run twice more on each side, each of them gets the same result on both sides at least once, and the one that looked worst (serve-http2-lifecycle.test.ts) fails 3 of 5 runs on main and 1 of 5 here. The files touched after that run were run again (191, then 161 files), with the same outcome. 70 of the 1,322 import bun:internal-for-testing, which a release build only allows with BUN_FEATURE_FLAG_INTERNAL_FOR_TESTING and BUN_GARBAGE_COLLECTOR_LEVEL set, so they failed to load on both sides in that run. Run again on both sides with the two variables (3,682 tests pass on main): 67 are the same, and the other 3 are the same when run on their own. I did not run anything with a debug build: there is no native change.
• No hunk is unnecessary. For each hunk: revert it, run bun check, keep the revert if there is still no error. 504 hunks were reverted that way, most of them workarounds that the bun-types fixes above made unnecessary. 2,908 hunks are left.
• bun test test/integration/bun-types/bun-types.test.ts: 22 pass, with and without lib.dom.

Other bugs in tests that the type errors pointed at. Not fixed here

Each was confirmed by reading what the test calls or by running it. They need a service, another OS, the network, or a decision about what the test should do. Paths are relative to test/.

• js/bun/http/bun-serve-ssl.test.ts:128: The loop over serverNames only sets the Host request header, which never selects the TLS SNI name in Bun's fetch; SNI is always the URL hostname (localhost). The localhost2.com entry of the valid 2 fixture is never exercised, even if keepAlive is corrected to keepalive; tls: { serverName } would be needed.
• js/bun/perf_hooks/histogram.test.ts:537: The "toJSON method" test wraps all its assertions in if (typeof h.toJSON === "function"). Bun's histogram has no toJSON, so the test only logs a message and passes with zero assertions.
• js/node/http/node-http.test.ts:1340: "should noop keepSocketAlive" never calls agent.keepSocketAlive(): the call sits in the request handler of a server that never listens, so the only assertion that runs is agent.keepAlive === true. The dead handler also passes a ClientRequest instead of a socket and calls server.end(), which does not exist, and keepSocketAlive is no longer a no-op in Bun.
• js/sql/sql.test.ts:1224: "Transaction throws on uncaught named savepoint" calls the misspelled sql.savepoit("watpoint", ...). The call throws TypeError: sql.savepoit is not a function, .catch(() => "fail") maps any error to "fail", and the test passes without ever creating a savepoint.
• js/valkey/reliability/connection-failures.test.ts:307: "should handle rapid connection/disconnection" pushes client.close() results into promises and awaits Promise.all, but close() returns undefined, so nothing is awaited. The clients never connect either, because new RedisClient() is lazy. The test has no expect and opens no socket.
• js/web/abort/abort.test.ts:9: "AbortSignal > spawn test" never runs the 23 tests in abort.ts. It copies them to <tmpdir>/bun.test.XXXX/abort.test.ts, then runs bun test /abort.test.ts with cwd: os.tmpdir(); that filter matches nothing and the child exits 1, but the test only asserts that stderr lacks "✗" and never checks the exit code. abort.ts is referenced nowhere else.
• regression/issue/25589-frame-size-connect.test.ts:147: The three tests in HTTP/2 FRAME_SIZE_ERROR with @connectrpc/connect-node never send a request: each one only does assert.ok(transport) on the object returned by createGrpcTransport(). makes basic gRPC request without FRAME_SIZE_ERROR makes no gRPC request, the 50-header interceptor in transport with large headers in interceptor never runs, and the EchoService definition is unused.
• bundler/cli.test.ts:271: describe.concurrent("bun build", () => {...}, 10_000) passes a timeout as third argument to describe. describe parses it but never applies it, so the tests in the block run with the default timeout instead of 10 s.
• js/bun/http/async-iterator-stream.test.ts:245: "async generator aborted doesn't crash" has its only assertions (toBeInstanceOf(DOMException), name === "AbortError") inside catch; if fetch resolved instead of rejecting, the test would pass with zero assertions. Today fetch does reject, so the assertions run.
• js/bun/http/bun-serve-ssl.test.ts:144: The last fetch of the valid/valid 2 tests (Host: "badhost.com") assigns const res and the test ends without any assertion on it, so the only thing checked is that the fetch does not reject.
• js/bun/image/image.test.ts:1425: "BMP 32-bit BI_RGB is XRGB" passes { backend: "bun" } to the Bun.Image constructor, which has no such option, so it is silently ignored. The backend is the process-global Bun.Image.backend. On macOS and Windows that global is "system" at this point, so the test decodes through ImageIO/WIC and not through Bun's own BMP decoder, which it means to cover.
• js/bun/perf_hooks/histogram.test.ts:474: "percentiles map properties" asserts that the values of h.percentiles are bigint and equal to those of h.percentilesBigInt. This bakes in Bun's divergence from Node, where percentiles holds numbers. In Node the assertion only holds because both getters return the same Map object, which the percentilesBigInt getter has just refilled.
• js/bun/test/parallel/test-http-get-can-use-Agent.ts:7: test-http-get-can-use-Agent.ts and test-https-get-can-use-Agent.ts make real requests to google.com, which the repo's test rules forbid ("Never contact the public internet"). The tests depend on external network access.
• js/bun/util/filesink.test.ts:74: Bun.file(path).stream(64), commented "test it on a small chunk size", has no effect. The chunk size is used only for in-memory blobs and is dropped for file-backed ones, so the FIFO reader runs with the default chunking.
• js/first_party/ws/ws.test.ts:172: In the send() tests the typeof data === "string" branch is dead code: the ws client always emits a Buffer, and the echo server re-sends the Buffer it received, so string messages come back as binary frames and take the else branch (isBinary true). expect(isBinary).toBeFalse() never runs, so no test in the file checks isBinary === false on a client socket (only server sockets are checked, in isBinary and handles data passed along with the upgrade request).
• js/node/tls/test-system-ca-https.test.ts:40: test.skip(skipReason) is called from inside the running test to skip it. bun:test throws Cannot call test.skip() inside a test. Call it inside describe() instead., so on a Linux machine with no system CA bundle the test fails instead of being skipped (reached only with BUN_TEST_ALLOW_NET=1; otherwise the whole test is test.skip).
• js/web/fetch/response.test.ts:52: The print size test snapshots Bun.inspect(new Response(Bun.file(import.meta.filename))), which prints the size of the test file itself. The snapshot Response (8.0 KB) holds only while the file is 8000 to 8049 bytes, so any edit that moves the size out of that window breaks the test, including adding a test to the file.

Gaps in bun-types that are left. The tests use a cast there, never @ts-expect-error, so fixing the types breaks nothing

Each was checked against the runtime (release build) and the current declarations.

Web globals without lib.dom:

• Request#clone(), Response#clone(), formData() and bytes() are inherited from undici-types and return undici's Request / Response / FormData / Uint8Array<ArrayBufferLike>. Bun.serve({ fetch: () => res.clone() }), new Response(await req.formData()) and const r: Request = req.clone() are errors.
• The global FormData has no [Symbol.iterator], and values() / entries() are typed as yielding string only.
• ReadableStream#getReader() returns the reader of node:stream/web, which is not assignable to the global ReadableStreamDefaultReader. So stream.getReader().readMany() does not type check.
• new Request(url: URL, init?) has no overload, and there is no RequestInfo.
• ResponseInit.headers is undici's HeadersInit, not Bun.HeadersInit (RequestInit overrides it). Bun.HeadersInit has no iterable member, so new Headers(map) is an error.
• port.onmessage = (e: MessageEvent) => {} on a MessagePort or BroadcastChannel is an error: the handler gets undici's MessageEvent, and Bun.MessageEventSource is undefined. MessageEventInit has no ports.
• Blob#stream(chunkSize): declared without parameters, two docs guides show blob.stream(1024).
• URLSearchParams#toJSON() returns string[] for a repeated key, typed Record<string, string>.
• WebAssembly.Exception and WebAssembly.Tag are missing.
• Client WebSocket: binaryType rejects "blob", send() / ping() / pong() reject a Blob, WebSocketEventMap has no ping / pong.
• Bun.WorkerOptions has no execArgv.

bun:test:

• jest.mock() and jest.now() are missing from namespace jest. jest.now() is in docs/test/dates-times.mdx.
• toHaveReturnedWith(), toHaveLastReturnedWith(), toHaveNthReturnedWith(n): expected is optional at runtime and in Jest's types.
• expect.extend({ toBeEven(received: number) {} }) is an error: the first parameter can only be unknown or any. Jest's types use any.
• expect({ value: 1, name: undefined }).toEqual({ value: 1 }), the example in the JSDoc of toStrictEqual, is an error.

Bun.*:

• Bun.JSON5.parse takes string only. Like Bun.TOML.parse, the runtime takes typed arrays, ArrayBuffer, DataView and Blob.
• Bun.YAML.stringify returns undefined for undefined, a function or a symbol. It is typed string, where TOML.stringify and JSON5.stringify are string | undefined.
• SyncSubprocess.exitCode is null when a signal killed the child, typed number.
• Bun.spawn: cmd and stdio reject readonly arrays, stdin rejects ArrayBuffer / SharedArrayBuffer. The error lands on cmd ("does not exist in type 'string[]'").
• Bun.udpSocket({ socket: { error(socket, error) {} } }): the runtime calls error with one argument, the error, and this is the socket. The sockets have [Symbol.dispose], undeclared.
• Bun.serve({ unix, http2 }) and { unix, idleTimeout } are errors: those options are only on HostnamePortServeOptions. server.fetch(url, init) takes one parameter. WebSocketHandler.message is required, the runtime wants any one handler.
• Bun.connect({ fd, socket }) has no overload, although Bun.FdSocketOptions is declared.
• Bun.TLSOptions lacks crl, sigalgs, ecdhCurve, allowPartialTrustChain, sessionTimeout. The Error of handshake() and getAuthorizationError() always has a code, undeclared.
• BuildConfig.metafile is boolean. string and { json?, markdown? } are documented and work.
• Bun.Transpiler: no minify option, scan() / scanImports() take no loader, transform(code, loader) rejects json, toml, yaml, text and others.
• BuildMessage#notes, line, column and ResolveMessage#line, column are missing.
• Bun.file("s3://...", s3Options) is an S3File at runtime, typed BunFile. Bun.write(dest, data, options) does not take S3Options, and Bun.write(S3File, Response | Request) has no overload.
• BunFile#write() rejects a Blob. Its options are typed { highWaterMark }, the runtime reads createPath and type.
• Bun.hash(data) always returns a bigint, typed number | bigint.
• Bun.peek(rejected) returns the rejection reason, typed Promise<T> | T. The example in docs/runtime/utils.mdx does not type check.
• new Bun.CryptoHasher(algorithm, hmacKey) rejects an ArrayBuffer key.
• RedisClient: psubscribe(), punsubscribe(), pubsub() are missing, KeyLike excludes ArrayBuffer.
• sql.array() rejects typed arrays, and Bun returns int[] columns as Int32Array.
• $.ShellPromise has no bytes().
• Bun.WebView overloads addEventListener for CDP events, not removeEventListener.
• JSCallback (bun:ffi) has [Symbol.dispose], undeclared.

Runtime behavior noticed on the way

Each was reproduced with the release build, and compared with Node 26.3 where that applies.

• src/js/internal/sql/shared.ts:1342: sql.close({ timeout: 0 }), documented as closing all connections immediately, behaves like close() with no timeout and waits for pending queries, so it never resolves while a connection is stuck mid-handshake. hasTimeout = !!timeout is false for the number 0, so the timeout === 0 branch is only reached by the string "0". sql-close-pending-connection.test.ts passes "0" to get the forced close.
• src/ast/scope.rs:494: Bun accepts an ES module with two top-level function f / export function f declarations and silently keeps the last one. Node rejects the same file with SyntaxError: Identifier 'f' has already been declared, because top-level function declarations are lexical in a module. Bun also does not report the duplicate export name.
• src/jsc/bindings/JSNodePerformanceHooksHistogram.cpp:232: Histogram.percentiles returns a Map with bigint values in Bun (Map { 0: 5n, 100: 5n }), where Node returns numbers (Map { 0 => 5, 100 => 5 }). getPercentiles has the same body as getPercentilesBigInt.
• src/jsc/bindings/JSNodePerformanceHooksHistogramPrototype.cpp:39: perf_hooks.createHistogram() objects have no toJSON() in Bun. JSON.stringify(histogram) gives {}, where Node gives {"count":1,"min":5,"max":5,"mean":5,"exceeds":0,"stddev":0,"percentiles":{...}}.
• src/jsc/bindings/webcore/JSDOMFormData.cpp:314: A plain Blob appended to a FormData without a filename comes back from get() and from Response.formData() as instanceof File with name === undefined and constructor.name === "Blob", and is serialized with filename="". The XHR spec and Node give such an entry the name "blob" (filename="blob"). test/js/web/html/FormData-multipart-serialization.test.ts asserts the current behaviour (name: undefined, filename="").
• src/runtime/ffi/FFI.h:222: Calling a cc()-compiled function whose argument is "cstring" with a JS string or a CString object segfaults, while the same call through dlopen works and the shared types allow string. This is the "FIXME: bus error" behind the skipped block in test/js/bun/ffi/cc.test.ts.
• src/js/node/inspector.ts:526: inspector.Session#post(method) without a callback returns the result object in Bun and throws synchronously on an error such as an unknown method. Node returns undefined and does not throw. test/js/node/inspector/inspector-profiler.test.ts asserts the Bun-only return value, e.g. expect(session.post("Profiler.enable")).toEqual({}).
• src/runtime/crypto/PBKDF2.rs:164: crypto.pbkdf2(password, salt, iterations, keylen, "md55") with no callback throws ERR_CRYPTO_INVALID_DIGEST in Bun and ERR_INVALID_ARG_TYPE (The "callback" argument must be of type function) in Node, because Bun validates the digest name before the callback. The digest test in test/js/node/crypto/pbkdf2.test.ts omits the callback and so pins the Bun-only order.

[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

Beyond the inline findings, I also checked the new conditional return type of Bun.TOML.stringify against the runtime (src/runtime/api/TOMLObject.rs:65-84): arrays, Dates, Temporal objects and primitives at the top level throw rather than return undefined, so string for object inputs and undefined only for undefined/function/symbol matches what the runtime actually returns.

Extended reasoning...

The change is a 670-file sweep of type-only edits across test/ plus declaration changes in packages/bun-types (test.d.ts, bun.d.ts, globals.d.ts) and a rewritten test/tsconfig.json; it touches no security-sensitive surface. The bug hunt stopped at its finding cap rather than running dry, and the inline findings on the bun-types declaration changes are the part a human should weigh, so this is not an approval.

Additional findings (outside the current diff — GitHub can't attach inline comments there):

• 🟡 packages/bun-types/test.d.ts — nit: Users calling test.skip("reason") with only a label still get a type error after this PR, even though the runtime accepts it exactly like test.todo("label"), which this PR fixes. The diff adds the label-only overload to todo at packages/bun-types/test.d.ts:532 but leaves skip: Test<T> at test.d.ts:524 (and Describe.skip at test.d.ts:242) without it, and instead silences the two in-tree callers with (test.skip as any)(...). Fix: declare skip: Test<T> & ((label: string) => void) (and the Describe twin) so the types mirror the runtime, then drop the as any wrappers at test/regression/issue/09469.test.ts:5 and test/js/node/tls/test-system-ca-https.test.ts:40. [also at: packages/bun-types/test.d.ts:532 - nit: users of bun-types still get a type error for test.skip("label") and describe.skip("label"), which the runtime accepts exactly like .todo, and this PR hides the two in-tree callers behind as any instead.]

  Why this was flagged

  The runtime treats skip and todo the same for a missing callback: src/runtime/test_runner/ScopeFunctions.rs:152 maps SelfMode::Skip | SelfMode::Todo => CallbackMode::Allow, so test.skip("label") is accepted. This PR adds todo: Test<T> & ((label: string) => void) at packages/bun-types/test.d.ts:532, but skip at test.d.ts:524 stays Test<T>, which requires a function. Rather than add the overload, the diff wraps the two callers that use label-only skip in (test.skip as any)(...) at test/regression/issue/09469.test.ts:5 and test/js/node/tls/test-system-ca-https.test.ts:40. On the base branch those sites were plain test.skip(...) calls that typechecked against an incomplete declaration; after merging, any user writing test.skip("label") still gets TS2554 while test.todo("label") now typechecks, and the repo's own .d.ts rule (declare only what is implemented, never as any to silence a call site) is not met for skip.

  Verification: src/runtime/test_runner/ScopeFunctions.rs:152 maps SelfMode::Skip | SelfMode::Todo => CallbackMode::Allow, so a label-only skip call is accepted. packages/bun-types/test.d.ts:532 adds todo: Test<T> & ((label: string) => void); while line 524 remains skip: Test<T>;, so test.skip("label") is still TS2554. test/regression/issue/09469.test.ts:5 is cast with as any instead.

[Jarred-Sumner]

Review, the finding outside the diff: test.skip("label") and describe.skip("label") type check as of 0581fb7, like todo (ScopeFunctions.rs maps SelfMode::Skip | SelfMode::Todo to CallbackMode::Allow, and a file with both reports 1 skip). The two (test.skip as any)(...) are gone, so 09469.test.ts and test-system-ca-https.test.ts are the same as on main again.

CI on c59a61c, build 123496: the one hard failure is test/js/bun/spawn/spawn.test.ts on debian 13 x64-asan, stdout reader of an unref'd child and process lifetime > an idle reader stopped at the highwater mark does not keep the process alive. This PR changes 4 lines of that file, all erased casts, none in that test. The same test fails on builds of unrelated branches from the same hours: 123480 (hard failure), 123485 and 123490 (passed on retry). claude-find-issues fails on every PR at the moment, before it reads anything.

[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

Still open from earlier reviews (5):

• Unresolved: 5 minor or pre-existing.

[claude]

I re-reviewed after the latest push and found no bugs; the follow-ups to the earlier inline comments look right, but with 668 files and public bun-types changes a human look is still worthwhile.

What was reviewed:

• 21aa092a: ((label) => void) & Test<T> / & Describe<T> ordering — the one-arg signature is tried first (so test.skip("x", fn) falls through on arity) and Parameters<> still reads the last Test<T> signature; the new fixture lines in test/integration/bun-types/fixture/test.ts lock this in.
• Test<T> gaining (label, options, fn) ahead of (label, fn, options?): Parameters<typeof test> is unchanged because it takes the last signature.
• each(table: readonly T[]) widening and expect(): Matchers<undefined> — no new overload-resolution regressions spotted beyond what was already raised inline.

Extended reasoning...

The PR is a type-error sweep across test/ (668 files) plus changes to the public declarations in packages/bun-types (test.d.ts, bun.d.ts, globals.d.ts), test/tsconfig.json restructuring, and small typed edits in packages/bun-error, packages/bun-release and scripts/build. It touches no security-sensitive surface. The latest commit only reorders the skip/todo intersection types and adds fixture assertions, which addresses the previously raised Parameters<> regression. The sheer size, the public .d.ts surface (including the WebView back/forward rename and overload reordering that affects downstream inference), and my inability to run the bun-types fixture test in this session are what rule out approving.

Still open from earlier reviews (2):

• Unresolved: 2 minor or pre-existing.

[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

[robobun]

^{Updated 12:43 AM PT - Oct 6th, 2026}

❌ @Jarred-Sumner, your commit 37c653b has 2 failures in Build #123529 (All Failures):

• test/js/sql/sql-close-pending-connection.test.ts - code 1 on 🍎 27 aarch64
• test/js/node/net/node-net.test.ts - code 1 on 🍎 27 aarch64

---

🧪   To try this PR locally:

bunx bun-pr 44614

That installs a local version of the PR into your bun-44614 executable, so you can run:

bun-44614 --bun

[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

[claude]

🟡 nit (optional): Users without lib.dom who call new Blob([...]).slice("text/plain") or .slice(1, "text/plain") get a type error after merging, although the runtime accepts both. The new Blob.slice declaration at packages/bun-types/globals.d.ts:1517 lists only (start?, end?, contentType?), while the shared runtime implementation also takes a string first or second argument. Fix: give the new Blob.slice the same three overloads BunFile.slice already declares at packages/bun-types/bun.d.ts:2696-2715, so a plain Blob no longer needs a BunFile cast to type-check. The PR hides the gap at test/js/web/fetch/blob.test.ts:66 with (blob as Bun.BunFile) on a plain new Blob(["Bun", "Foo"]).

Why this was flagged

A bun-types consumer without lib.dom writes new Blob(["a"]).slice("text/plain") or .slice(1, "text/plain"). packages/bun-types/globals.d.ts:1517 is the only slice on interface Blob, typed slice(start?: number, end?: number, contentType?: string): Blob, so a string in the first or second position is TS2345. At runtime get_slice in src/runtime/webcore/Blob.rs:1844-1851 moves a string found in args[0] or args[1] into the contentType slot for every Blob, and test/js/web/fetch/blob.test.ts:26-66 asserts blob.slice("text/plain;charset=utf-8").type for a plain new Blob(["Bun", "Foo"]). The PR makes that line type-check by casting the plain Blob to Bun.BunFile (blob.test.ts:66), whose declaration at packages/bun-types/bun.d.ts:2696-2715 has the three overloads the runtime implements. On the base branch slice was not declared on Blob at all without lib.dom, so the declaration this PR adds is new surface that is narrower than the runtime it documents.

Verification: nit — triggers when a bun-types consumer without lib.dom calls Blob#slice with a string in the first or second position. The diff adds exactly one slice to interface Blob at packages/bun-types/globals.d.ts:1517. The runtime in src/runtime/webcore/Blob.rs:1844-1851 explicitly shifts a string in position 0 or 1 into the contentType slot for every Blob. Nothing that compiled on the base breaks.

[Jarred-Sumner]

I tried it, and it breaks more than it fixes. With slice(start?: number, contentType?: string) and slice(contentType?: string) added to the global Blob, 9 of the 22 cases in bun-types.test.ts fail, starting with the fixture for #24154:

24154.ts:5:3  TS2322: Type 'import("node:buffer").Blob' is not assignable to type 'Blob'.
  Types of property 'slice' are incompatible.
    Types of parameters 'end' and 'contentType' are incompatible.
      Type 'string' is not assignable to type 'number'.

That is async function example(): Promise<Blob> { return await (await fetch("foo")).blob(); }: response.blob() is the Blob of node:buffer, whose slice has the one standard signature, so it stops being assignable to a global Blob that has more. #41809 came to the same conclusion. The one call in blob.test.ts that uses the string-first form keeps its cast.

[claude]

Code review completed

Nothing new to post: everything this review found is already covered by existing comments on this pull request or didn't merit a separate one.

Still open from earlier reviews (1):

• Unresolved: 1 minor or pre-existing.

[Jarred-Sumner]

CI on 457443d, build 123517: the only hard failure is test/js/bun/s3/s3.test.ts on ubuntu 25.04 x64 and alpine 3.23 aarch64, in the tests that talk to the real R2 bucket:

S3Error: Please look at https://www.cloudflarestatus.com for issues or contact customer support.
 code: "ServiceUnavailable"

A different test fails on each lane, the same file passes on retry on other lanes of that build, and cloudflarestatus.com reports "Partial System Outage" at the moment. The empty commit runs CI again.

All 16 Windows test shards pass (2019 x64 and 11 aarch64), which is what covers the Windows branch of the toHaveBins() change.

[claude]

Code review completed

Nothing new to post: everything this review found is already covered by existing comments on this pull request or didn't merit a separate one.

Still open from earlier reviews (1):

• Unresolved: 1 minor or pre-existing.

[Jarred-Sumner]

CI on af27923, build 123524: R2 is fine this time. The hard failure is spawn.test.ts on debian 13 x64-asan again, an idle reader stopped at the highwater mark does not keep the process alive, the same test as on the first build of this PR (when every test file still emitted the same JavaScript as on main).

How often that test fails elsewhere, from the annotations of builds 123420 to 123525: of the 47 finished builds of other branches, it is a hard failure in 7 (15%) and passes on retry in 19 more (40%).

Hard failures: 123449, 123452, 123469, 123479, 123480, 123489, 123520, on 6 unrelated branches.

Running CI again.

[claude]

Code review completed

Nothing new to post: everything this review found is already covered by existing comments on this pull request or didn't merit a separate one.

Still open from earlier reviews (1):

• Unresolved: 1 minor or pre-existing.

[Jarred-Sumner]

CI on f9c9530, build 123525: spawn.test.ts passes this time. The hard failure is test/js/web/timers/timer-gc-roots.test.ts on debian 13 x64-asan, an RSS threshold:

error: expect(received).toBeLessThan(expected)
Expected: < 8
Received: 8.07421875
✗ AbortSignal.timeout is released when its wrapper is collected > AbortSignal.any([timeout, controller.signal]).abort releases the timeout

This PR does not touch that file, there is no native change, and the measurement runs in a bun -e child that does not import harness. In the annotations of builds 123380 to 123526, the file fails and passes on retry in 17 of the 58 finished builds of other branches (29%), for example 123519, 123507, 123505.

Running CI again.

[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

Still open from earlier reviews (1):

• Unresolved: 1 minor or pre-existing.

[claude]

Code review completed

Nothing new to post: everything this review found is already covered by existing comments on this pull request or didn't merit a separate one.

Still open from earlier reviews (1):

• Unresolved: 1 minor or pre-existing.

[Jarred-Sumner]

CI on 37c653b, build 123529: passed, on every platform. This is the first run of the test fixes of that commit on macOS and Windows.

The 2 failures in the status comment are on darwin 27 aarch64, which is a soft-fail lane: node-net.test.ts (a socket destroyed while connecting ... can connect again at once, connectionAttemptFailed ECONNRESET) and sql-close-pending-connection.test.ts (the process exits after the connection timeout of a dial that never completes). The edits to those two files here are erased by the transpiler. The same two files fail together on that lane in 14 of the 49 finished builds of other branches between 123440 and 123529, for example 123519, 123510, 123507, 123503.