[robobun]

Problem

• src/codegen/generate-classes.ts emits a js<Class>Constructor custom getter for each of the 67 constructible generated classes. Nothing installs it on a prototype and nothing references it.
• src/codegen/generate-jssink.ts has the same pattern: function<Sink>__getter for the 7 sinks, with no reference.
• A few handwritten items have no users left: createStreamsBoundHandler (last caller removed in Bun.serve direct streams: flush on controller.close(), end the response once, call cancel() only on a client abort #41894), the empty POSIX signalHandler(int), two builtin names, two write-only struct fields, and some re-exports.

Fix

• Remove both getter templates. ZigGeneratedClasses.cpp shrinks by 871 lines, JSSink.cpp and JSSink.h by 63.
• Remove the six sink constructor accessors in ZigGlobalObject.h that only the sink getter called, and the other items listed in Notes. Each one has zero references in src/, packages/, the codegen scripts and the generated output.
• Verified: bun bd builds and links. bun run rust:check-all is 12 of 12 ok. arraybuffersink.test.ts, streams.test.js, cpu-prof.test.ts and test/internal/source-lints/ pass. X.prototype.constructor === X holds for the generated classes, before and after.
• No test file: the change only deletes unreferenced code, so no behavior changes, and test/internal/source-lints/CLAUDE.md asks for no tests for dead symbols.

Background

• generate-classes.ts turns each *.classes.ts definition into a C++ wrapper class, a prototype class and a constructor class. The constructor property of a prototype comes from the constructor class, not from this getter.
• generate-jssink.ts does the same for the JSSink stream sink classes.
• No open dead-code PR removes any of these lines. Remove dead code from bun_core, the JSC bindings, the debugger, and 24 other crates #41385 edits lines next to the sink accessors in ZigGlobalObject.h, so one of the two needs a rebase after the other merges.

Notes

Removed symbols:

• js${typeName}Constructor getter template (generate-classes.ts). A relink of the debug binary with --gc-sections --print-gc-sections drops all 67 instances.
• function${name}__getter template (generate-jssink.ts). The same relink drops all 7.
• Zig::GlobalObject::FileSink(), HTTPResponseSink(), HTTPSResponseSink(), NetworkSink(), FetchRequestBodySink(), HTMLRewriterSink(). ArrayBufferSink() stays, BunObject.cpp and BunStreamConsumers.cpp call it. The *Structure() accessors stay, JSSink.cpp calls them.
• Bun::WebStreams::createStreamsBoundHandler (WebStreamsMisc.cpp, WebStreamsInternals.h).
• Bun::signalHandler(int) in BunProcess.cpp. The body was empty on POSIX. The only reference, &signalHandler, is inside the Windows branch and takes the uv_signal_t* overload, which stays.
• onClose and onDrain in BunBuiltinNames.h. No $onClose or $onDrain in src/js, no onClosePublicName, onClosePrivateName, onDrainPublicName or onDrainPrivateName in C++. bundle-functions.ts adds a private name on its own when a builtin starts to use one.
• CPUProfilerConfig::interval. run_command.rs passes the interval to set_sampling_interval directly.
• MultiPartUpload::global_this. Both constructors wrote it, nothing read it.
• Re-exports with no user on Linux, Windows or macOS: ten names in runtime/image/mod.rs, mode_from_js and dirent::Dirent in runtime/node.rs.

Test counts: streams.test.js 549, arraybuffersink.test.ts 14, cpu-prof.test.ts 12, test/internal/source-lints/ 172.

Method: one pass that marks every pub item pub(crate) per crate and reads the dead_code output, then a second pass that tags each hit #[deprecated] and collects the use sites from cargo check --workspace on 9 targets. For C++, the --print-gc-sections list from a relink, then rg for each name.

Found but left alone:

• About 400 more lines of Rust with zero uses on every target. Open PRs Remove dead code from the Windows bunx shim, bun_sys, libuv_sys and mimalloc_sys #40172, Remove dead code from the WebCore bindings and 20 Rust crates #40525, Remove dead code from the inspector protocol package, bun_jsc, bun_install, and the Windows named pipe modules #40557, Remove dead code from bun_jsc, bun_core, the bindgenv2 codegen, 15 error types, and the C++ bindings #40915, Remove dead code from bun_bundler, bun_install, bun_runtime, bun_parsers, and the JSC private host functions #41088, Remove dead code from bun_js_parser, bun_sys, bun_perf, the bake router, and the root-certs script #41127, Remove dead code from bun_collections, bun_core, the JSC bindings, and 37 re-exports #41268, Remove dead code from bun_collections, libuv_sys, bun_core, and the build scripts #41335 and Remove dead code from bun_core, the JSC bindings, the debugger, and 24 other crates #41385 already remove nearly all of them.
• mockedFunction in BunBuiltinNames.h looks unused to rg, but BunCommonStrings.cpp builds the accessor name with ##. The build caught it.
• 105 Feature variants in src/css/compat.rs are never constructed. The file is generated from upstream data, so this PR does not edit it.

[robobun]

^{Updated 8:34 PM PT - Sep 10th, 2026}

✅ @robobun, your commit 552d3876fb16173cf496407d7faa856b11bb04fe passed in Build #114110! 🎉

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🧪   To try this PR locally:

bunx bun-pr 42266

That installs a local version of the PR into your bun-42266 executable, so you can run:

bun-42266 --bun

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Essentials

Run ID: a56d78f8-847b-4add-adb8-8d828b8090a1

📥 Commits

Reviewing files that changed from the base of the PR and between f4f2a7c and 552d387.

📒 Files selected for processing (2)

• src/runtime/webcore/s3/client.rs
• src/runtime/webcore/s3/multipart.rs

Included review availability: Your plan provides up to 10 included reviews per hour; 9 remain after this review.

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Walkthrough

The changes remove obsolete generated getters and stream helpers, narrow runtime public exports, remove profiler configuration state, specialize signal handling for Windows, and remove global_this from multipart upload state.

Changes

Runtime binding and API cleanup

Layer / File(s)	Summary
Generated constructor and sink cleanup src/codegen/generate-classes.ts, src/codegen/generate-jssink.ts	Generated bindings no longer emit custom constructor or sink getter declarations and implementations.
Stream binding helper removal src/jsc/bindings/ZigGlobalObject.h, src/jsc/bindings/webcore/streams/*	Sink constructor accessors and the shared createStreamsBoundHandler declaration and implementation were removed.
Public API and profiler surface cleanup src/js/builtins/BunBuiltinNames.h, src/jsc/BunCPUProfiler.rs, src/runtime/cli/run_command.rs, src/runtime/image/mod.rs, src/runtime/node.rs	Unused builtin names, profiler interval state, and selected public re-exports were removed.
Windows signal handler specialization src/jsc/bindings/BunProcess.cpp	signalHandler is now defined only for Windows and uses the libuv callback signature.
Multipart upload lifetime state removal src/runtime/webcore/s3/client.rs, src/runtime/webcore/s3/multipart.rs	Multipart upload construction no longer stores or initializes global_this; the lifetime comment uses the direct borrow guarantee.

Suggested reviewers: dylan-conway, jarred-sumner, alii

Priority: ⬇️ Low

Merge Risk: ⚪ Minimal · up to 552d3

The cleanup preserves the S3 upload lifetime guarantees and introduces no identified runtime or data-integrity risk.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly summarizes the primary change: removing dead code from class and sink code generation, stream bindings, and bun_runtime.
Description check	✅ Passed	The description explains the problem, lists the fixes, and provides detailed build, check, and test verification. It covers the template requirements despite using additional headings instead of the e…

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_{Comment @coderabbitai help to get the list of available commands.}

[robobun]

Status

• Scope: dead code that no other open dead-code PR removes. I compared each deletion with the diffs of the 26 open sweep PRs, file by file.
• How I found it: a per-crate pub to pub(crate) pass to read rustc's dead_code output, a #[deprecated] tag pass to collect use sites from cargo check --workspace on 9 targets, and the --print-gc-sections list from a relink of the debug binary for C++.
• How I verified it: rg for each name across src/, packages/, src/codegen/ and build/debug/codegen/, then bun bd, bun run rust:check-all (12 of 12 ok), arraybuffersink.test.ts, streams.test.js, cpu-prof.test.ts and test/internal/source-lints/.
• Review: the one review thread (a long comment in s3/client.rs) is fixed in 552d387 and resolved. CodeRabbit has no actionable comments.

[claude]

LGTM — mechanical dead-code sweep, all removals check out.

What was reviewed:

• Grepped for every removed symbol: the six sink constructor accessors, createStreamsBoundHandler, onClose/onDrain private names, and the removed Rust re-exports have zero remaining references in src/.
• &signalHandler at BunProcess.cpp:1652 is inside the #else of #if !OS(WINDOWS), so the POSIX overload was genuinely dead.
• Confirmed global_static in upload_stream is still consumed by S3UploadStreamWrapper.global (line 957), so the updated JSC_BORROW comment is accurate; writable_stream no longer needs one.
• js${typeName}Constructor is not referenced by any HashTableValue emitter in generate-classes.ts — the prototype's constructor comes from LazyClassStructure/createConstructor.

Extended reasoning...

Overview

This PR is a targeted dead-code sweep across 13 files (+4/−79). It removes two unreferenced codegen templates (js${typeName}Constructor custom getter in generate-classes.ts, function${name}__getter in generate-jssink.ts), the six ZigGlobalObject sink-constructor accessors that only those getters called, an empty POSIX signalHandler(int) overload, the unused createStreamsBoundHandler helper, two builtin-name macros, and a handful of unread Rust struct fields and re-exports (CPUProfilerConfig::interval, MultiPartUpload::global_this, image/node module re-exports). No behavior is added; every hunk is a deletion or a struct-init-site adjustment for a deleted field.

Security risks

None. Nothing here touches auth, crypto, input parsing, or any user-reachable validation path. Deleting an unread GlobalRef field on MultiPartUpload cannot affect GC rooting because GlobalRef is a borrow of the process-lifetime global object, not a JS heap root, and the S3 wrapper still holds its own global field where needed.

Level of scrutiny

Low-to-moderate. The change is mechanical and the PR description documents a rigorous verification method (--gc-sections --print-gc-sections relink for C++, per-crate pub(crate) + #[deprecated] sweep across 9 Rust targets, bun bd link, rust:check-all 12/12). I independently grepped the tree for every removed symbol and confirmed zero remaining call sites; spot-checked that the sole &signalHandler reference is Windows-gated; confirmed the removed js<Type>Constructor getter is not wired into any prototype HashTableValue (constructor linkage goes through LazyClassStructure::setConstructor instead); and verified mode_from_js callers in node_fs.rs go through types::mode_from_js directly, not the removed top-level re-export.

Other factors

No CODEOWNERS entries cover the changed paths. The two bot inline threads at client.rs:902 were addressed by commit 552d387, which corrected the JSC_BORROW comment to name the actual storage site (S3UploadStreamWrapper) after the MultiPartUpload field was dropped — that fix is correct. REVIEW.md explicitly requires deleting dead code and naming the deletions in the description, which this PR does thoroughly. The change is small, self-contained, and compiles/links on all targets per the description; there is nothing here a human reviewer would need to weigh in on.