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Included review availability: Your plan provides up to 5 included reviews per hour; 0 remain after this review. WalkthroughChangesThe request-body ownership documentation now covers shared references and releases the hive handle after fully buffered bodies become internal blobs. New ASAN subprocess tests cover aborted, terminated, collected, truncated, and fully buffered request lifecycles. Request body cleanup
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Status: ready for review. CI is green on the current head (Buildkite build 101599, 179 of 179 jobs). The earlier build had two Reproduced with the ASAN debug build and the script from the report ( The diff is one release in |
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I reviewed this PR and didn't find any bugs. Because it moves a refcount release point in RequestContext's request-body lifecycle — the most-scrutinized category in this codebase — a human look would still be worthwhile.
What was reviewed:
end_request_streamingruns on every end/abort path anddeinitcalls it first (line 856), so the removeddeinitrelease is covered.request_body_take_unrefis idempotent (replace(None)), so repeatedend_request_streamingcalls and the pre-existing early release atRequestContext.rs:4042compose safely.- The
scopeguard::defer!orders the release afterrequest_body_mut()/to_error_instance, so theLockedrejection still runs while the context holds its ref. - LSan tests follow harness conventions (
tempDir, drained pipes,skipIf(!isASAN), combined-object assertion).
Extended reasoning...
Overview
Moves the RequestContext's +1 release on the pooled request-body slot from deinit to end_request_streaming, so a handler promise that never settles (which pins the context past VM teardown via NativePromiseContext) no longer keeps buffered body bytes alive past the body pool's lifetime. Two comment updates in server_body.rs name the new release point, and two new LSan cells in serve-body-leak.test.ts cover client-abort and Worker-terminate.
Security risks
None. This is a leak fix; no user-controlled input parsing, no auth/crypto surface. The only risk class is memory safety (double-unref or use-after-unref of the body slot).
Level of scrutiny
High. Bun.serve's RequestContext is production-critical hot path, and REVIEW.md flags refcount balance as the most-blocked category. The change itself is tiny (one line moved into a scopeguard::defer!), and I verified: deinit still reaches the release via end_request_streaming_and_drain() at line 856; request_body_take_unref is a replace(None) so repeat calls are no-ops; the defer ordering keeps the context's ref live across the Locked rejection (which the PR notes may otherwise run on the slot's last ref); and no caller re-populates request_body after an end path. The PR description enumerates every post-end reader of the slot and why each is unreachable — that argument reads correct against the source, but it is exactly the kind of "provably balanced on every terminal path" claim a maintainer should sign off on.
Other factors
The PR description is unusually thorough (traces, related-PR analysis, per-path reasoning, full suite list). Tests are LSan-gated to the ASAN lane, use describe.concurrent, and the Worker cell's setImmediate hop is explained to avoid a race that would make the unfixed build pass. No prior human review comments to address.
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Updated 5:28 AM PT - Aug 20th, 2026
✅ @robobun, your commit 26cd2276e6c3a7a05f2b4ac594bb236966316507 passed in 🧪 To try this PR locally: bunx bun-pr 39660That installs a local version of the PR into your bun-39660 --bun |
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I reviewed this PR and didn't find any bugs. Because it moves a refcount release in RequestContext's body-slot lifecycle — the memory-safety category the review guide flags as most-blocked — a human look from someone familiar with this file would still be worthwhile.
What was reviewed:
request_body_take_unrefis idempotent (replace(None)), so the new release inon_buffered_body_chunkfollowed by thescopeguard::defer!inend_request_streaming(and again viadeinit→end_request_streaming_and_drain) cannot double-unref.- The
&mut bodyinto the hive slot is not touched after the release atRequestContext.rs:4136; the immediatereturnprevents a dangling deref. - The defer in
end_request_streamingfires afterbody.to_error_instance, so theLockedrejection runs on a live slot on all three return paths including the?error path. is_dead_requestis the only remaining reader ofself.request_bodyafter last-chunk; it handlesNonecorrectly.
Extended reasoning...
Overview
This PR changes when RequestContext releases its +1 ref on the pooled Body::Value slot that stores a buffered request body. Previously the release happened only in deinit; now it happens (a) immediately after the last buffered chunk is stored and resolved in on_buffered_body_chunk, and (b) via a scopeguard::defer! at the end of end_request_streaming for bodies that never completed. The explicit release in deinit is removed since deinit already calls end_request_streaming_and_drain first. Two comment-only edits in server_body.rs update the ownership doc, and five new tests cover LSan-verified leaks (client abort, parked pull(), Worker termination) and post-response body readability.
Security risks
None identified. This is an internal refcount-timing change with no user-facing input validation, auth, or crypto surface.
Level of scrutiny
High. This is a lifecycle/ownership change in RequestContext, which the repo's review guide calls out as the most-blocked category ("pair every acquisition with its release", "reference counts provably balanced on every terminal path"). The reasoning is subtle enough that the PR's own first revision missed a branch (on_abort with a response stream) and a behavioral regression (end_request_streaming rejecting a completed body's Locked value). The final revision addresses both, but the correctness argument depends on non-local invariants: that nothing reads the slot after the last chunk except is_dead_request, that the prepare-time Locked callbacks die with the value resolve consumed, and that Body::Value::resolve hands bytes to its consumer synchronously so releasing right after is safe. These claims look right from the code I read, but they're exactly the kind a maintainer who owns this file should confirm.
Other factors
- I verified the idempotence of
request_body_take_unref(dropsOption::Noneon repeat calls), so the multiple call sites ofend_request_streaming(lines 1410, 1486, 2264) plus the last-chunk release cannot double-unref. - I verified the
&mut bodyborrow into the hive slot at line 4115 is not used after the release at 4136 — there is an immediatereturn. - The
scopeguard::defer!ordering is correct: it fires afterto_error_instanceon theLockedbranch, after the readable-stream error branch, and on the?early-error path, always with the slot still live during the user-JS rejection. - The tests are well-constructed: three LSan cells gated on
isASAN && !isWindowswith subprocess isolation andBUN_DESTRUCT_VM_ON_EXIT, plus two in-process cells that exercise the behavioral fix (reading a complete body after the response). The PR states all five fail on main. - The comment-cop bot flagged the added comments; the author shortened them and the threads are resolved. The remaining comments state ownership facts, not workaround justifications, which is the repo's stated bar.
Given the subtlety of the refcount reasoning and that this is Bun.serve's per-request hot path, I'm deferring rather than approving.
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Inline comments:
In `@test/js/bun/http/serve-body-leak.test.ts`:
- Around line 418-425: Update the child socket setup around write and error
handling so short writes throw instead of logging, and socket.error rejects a
shared socket-failure promise. Add awaitWithSocketFailure and use it for both
aborted.promise waits and the handler progress wait, ensuring any child I/O
failure rejects immediately rather than leaving the test pending.
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test/harness.tstest/js/bun/http/serve-body-leak.test.ts
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🤖 Prompt for all review comments with AI agents
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Inline comments:
In `@test/js/bun/http/serve-body-leak.test.ts`:
- Line 425: Update the short-write error in the test’s write path to identify
the affected client socket, state the expected-versus-actual byte-count
violation, include the write failure cause when available, and provide a
concrete corrective action for the subprocess failure.
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Fix all unresolved CodeRabbit comments on this PR:
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I reviewed this PR and didn't find any bugs. Because it reworks the refcount lifecycle of RequestContext::request_body — a memory-safety change on a hot Bun.serve path — a human look would still be worthwhile.
What was reviewed:
- Traced every
request_bodyconsumer:request_body_take_unrefis idempotent (replace(None)),deinitstill releases viaend_request_streaming_and_drainat line 856, and thedefer_deinitearly return is covered. - Checked the
&mut bodyborrow atRequestContext.rs:4060ends at its last use (line 4130) beforerequest_body_take_unref()may free the slot; the immediatereturnprevents any post-free access. - Confirmed
on_start_buffering(line 4277) can't fire after the last-chunk unref, sinceresolveconsumes theLockedvalue that carried that callback. - The scopeguard in
end_request_streamingfires on both the?path and bothreturn Ok(...)paths, and runs afterto_error_instanceso the rejection acts on a live slot.
Extended reasoning...
Overview
The PR moves the RequestContext's release of its +1 on the pooled Body::Value slot from deinit to the two points where the context stops feeding the slot: the last buffered chunk in on_buffered_body_chunk, and a scopeguard::defer! in end_request_streaming for the incomplete-body path. It also removes the now-redundant explicit unref from deinit (which still releases via the end_request_streaming_and_drain call at its top). Two comments in server_body.rs are updated to point at the field doc. test/harness.ts gains a leakSanitizerEnv() helper, and serve-body-leak.test.ts gains seven cells: four LSan leak cells, one ASAN ordering cell, and two behavioral cells for reading a fully-buffered body after the response.
Security risks
None identified. This is a resource-lifetime fix; no user-controlled input parsing, auth, or crypto is touched.
Level of scrutiny
High. This is a refcount-lifecycle change in RequestContext, which the repo's own review guidance flags as the most-blocked category ("reference counts provably balanced on every terminal path"). The body: &mut Body::Value at line 4060 becomes dangling if used after request_body_take_unref() frees the slot's last ref; the diff places the unref immediately before return and the borrow's last use is at line 4130, so NLL ends it before the unref — but this ordering is load-bearing and only guarded by a comment. The scopeguard in end_request_streaming must fire after to_error_instance (which can enter JS and be the slot's last consumer), and it does — but the ordering-pinning ASAN cell is the only mechanical guard.
Other factors
The PR is unusually well-documented and well-tested: six of the seven new cells are stated to fail on main and pass with the fix, the LSan cells directly reproduce the reported leak, and the collected-Request cells prove the release is safe as the slot's last ref. All comment-cop and CodeRabbit threads are resolved. I traced every reader of self.request_body (is_dead_request, request_body_mut at 2281/4060/4277, on_start_buffering) and each is either idempotent on None or cannot fire after the new release points. I found nothing wrong. Deferring only because refcount-lifecycle changes on the request hot path are the canonical "maintainer should look" category, and the PR itself notes adjacent out-of-scope leaks (parked-context pool slot, cookies) that a maintainer may want to weigh in on.
The request context and the JS Request each hold a ref on the pooled Body::Value slot that stores a buffered request body. The context released its ref in deinit. A request parked on a promise that never settles (the handler's, or a response stream's pull()) is deinit'd only when GC collects that promise, and never when the VM is torn down first, so the body bytes outlived the body pool and LeakSanitizer reported them (allocated in on_buffered_body_chunk). The same late release made end_request_streaming reject a Locked value that request.body had created over a complete body, so reading the body after the response was sent gave "" or "The connection was closed". Release the context's ref as soon as the last chunk is stored and resolved, as the streaming arm of on_buffered_body_chunk already does. From then on only the Request owns the bytes. A body that never completes is still released in deinit.
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I reviewed this PR and didn't find any bugs. The single-line release in on_buffered_body_chunk mirrors what the streaming arm already does at RequestContext.rs:4036, and I traced the downstream readers (end_request_streaming, is_dead_request, deinit, on_start_buffering) to confirm they all tolerate request_body being None after the last chunk. Because this shifts a refcount release point on a shared pooled slot in Bun.serve's hot path, a maintainer look at the "nothing reads the slot after the last chunk" invariant would still be worthwhile.
What was reviewed:
- Confirmed
body(the&mutinto the hive slot) is last used at theresolvecall beforerequest_body_take_unref(), so the drop that may free the slot does not alias a live borrow. - Checked that
deinit's existingrequest_body_take_unref()at line 890 is idempotent overNone, so the incomplete-body path is unchanged. - The two open comment-cop flags on lines 153/4133 are length-heuristic hits on ownership docs; the author already justified them on the earlier round and REVIEW.md asks for exactly this kind of "who frees this, when" comment.
Extended reasoning...
Overview
The PR adds one line to src/runtime/server/RequestContext.rs: this.request_body_take_unref() at the end of the if last branch in on_buffered_body_chunk, releasing the request context's ref on the pooled body slot as soon as the final chunk is stored and resolved. The streaming arm of the same function already does this at line 4036. Two doc comments are updated to reflect the new release point, and two comments in server_body.rs are reworded to point at the field doc. Seven new test cells (~300 lines) in serve-body-leak.test.ts cover the leak (LSan under abort / parked pull() / Worker terminate / Request-collected-first), the resolve-before-drop ordering under ASAN, and the user-visible fix that a fully buffered body remains readable after the response is sent.
Security risks
None identified. This is a resource-lifetime change with no input parsing, auth, or trust-boundary implications. The risk class is memory safety (early release → UAF), which the tests address directly: the "resolves a pending read from the last chunk when the Request was collected" cell exercises the case where request_body_take_unref() is the slot's final deref, with ASAN watching the read that resolve performs from the slot just before the drop.
Level of scrutiny
High. This is native refcount-lifecycle code in RequestContext, the per-request state machine of Bun.serve, and REVIEW.md flags exactly this category ("every allocation has exactly one named owner, released exactly once") as the most-blocked. The change is small and mirrors an existing sibling arm, and the PR description enumerates every post-last-chunk reader of the slot with why each tolerates None. I verified those claims against the source: is_dead_request (line 842) and end_request_streaming (line 2278) both branch on Some, deinit (line 890) drops None harmlessly, and on_start_buffering is only reachable via the Locked value that resolve consumes here. That said, a maintainer who knows the full set of paths through RequestContext should confirm no other reader exists.
Other factors
The test coverage is thorough and follows harness conventions (subprocess pipes drained concurrently, bunEnv spread, tempDir, port: 0, socket-error wired to reject the awaited condition per the CodeRabbit round). All CodeRabbit threads are resolved. The two remaining unresolved inline comments are from the comment-cop length heuristic, not human review; the author already argued (and I agree) that the flagged comments state non-local ownership facts rather than justify a workaround. CI build #101596 is referenced as building on the head commit. Given the memory-safety sensitivity and that approval guidelines say not to approve changes to critical code paths, I'm deferring rather than approving.
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I reviewed this PR and found no bugs. The single-line refcount release in on_buffered_body_chunk mirrors the streaming arm and is placed after resolve so the context's ref still pins the slot while user JS runs; body is not touched after the drop. Because this adjusts refcount lifecycle on a hot Bun.serve path where the &mut into the hive slot is derived through unsafe, a human look is still worthwhile.
Checked: the new request_body_take_unref() call is idempotent with the existing one in deinit (RequestContext.rs:890); end_request_streaming tolerates request_body_mut() returning None; the body reference is last used at line 4127 before the drop at 4134; the two non-gated tests in the last describe block exercise the observable Locked-rejection fix on all platforms.
Extended reasoning...
Overview
The PR adds one functional line in src/runtime/server/RequestContext.rs: this.request_body_take_unref() at the end of the last-chunk branch of on_buffered_body_chunk, immediately after Body::Value::resolve and before return. This releases the request context's +1 on the pooled body slot as soon as the buffered body is complete, matching what the streaming arm already does at line 4036. The remaining diff is doc-comment updates on the request_body field and the two server_body.rs allocation sites, plus ~300 lines of new tests in serve-body-leak.test.ts.
Security risks
None identified. This is a resource-lifetime fix; no untrusted input parsing, auth, or crypto is touched.
Level of scrutiny
High. This is refcount lifecycle in Bun.serve's per-request hot path. request_body_mut() hands out an unbounded &mut Body::Value into the hive slot via unsafe { &mut (*h.as_ptr()).value }; the new call may free that slot, so the ordering against the live body borrow and against resolve (which enters JS) is load-bearing. I traced: (1) body is last dereferenced at line 4127 inside resolve, before the new drop at 4134; (2) during resolve the context still holds its ref, so reentrant JS cannot free the slot out from under body; (3) request_body_take_unref is replace(None) + drop, so the existing call in deinit:890 becomes a no-op rather than a double-deref; (4) end_request_streaming:2278 and is_dead_request handle None correctly.
Other factors
The PR description is unusually thorough and enumerates every reader of the slot after the last chunk. Six of seven new tests are stated to fail on main. The five LSan cells are gated to ASAN/non-Windows; the two behavioural tests (body readable after response) run everywhere. The comment-cop bot flagged the new comments repeatedly and the author pushed back with justification each time — those threads are all resolved. No human reviewer has weighed in yet. Given the unsafe-pointer subtlety and that this is a first human review of a memory-lifetime change in the server, I'm deferring rather than approving.
… waiting for GC (#39743) Fixes #39739. ### Problem - When a `Bun.serve` handler returns a promise that never settles, or a direct stream parks inside `pull()`, the end of the request does not free its context. The `NativePromiseContext` cell's ref keeps the context parked until GC collects the promise: the pool slot, the body slot, the stream refs, the sink, and `server.pendingRequests` all stay held. At VM teardown the cell's deref is skipped on purpose, so the context is never torn down. - With a response sink, `on_abort` also returns before `end_request_streaming`, so a pending body read (`request.text()` or `textStream()`) on a cut-off upload stays unrejected. ### Fix - The context remembers its live cell in a new `promise_cell` field. `reclaim_promise_cell` calls the cell's `take()` and derefs, so the context is torn down when the response ends. A later settle reaction gets null from `take()` and no-ops, which the reactions already tolerate. - Every termination path reclaims: `on_abort` (both branches), the end family (`end`, `end_stream`, `end_without_body`, `force_close`, `end_already_responded_stream`), and `server.upgrade()`. The 413 path and the upgrade need this because they disarm `onAborted`, so `on_abort` can never run after them. - `on_abort` orders the reclaim after `end_request_streaming`, and its sink branch now calls `end_request_streaming` itself. A `Used` body (`textStream()`) can only be rejected through a stream ref that `finalize_without_deinit` drops without erroring. - The settle paths clear the field after `take()`. The cell's destructor clears it during sweep, so the field never dangles. - Verified: test/js/bun/http/serve-pending-promise-abort-leak.test.ts (nine new tests, all fail on unfixed bun). Three of them are the parked pull() scenarios from #36567. Also body.test.ts, the serve stream, leak, and abort suites, serve.test.ts, bun-server.test.ts, serve-http3.test.ts, websocket-server.test.ts, the worker teardown tests, and the html-rewriter suites. ### Background - `NativePromiseContext` (src/jsc/bindings/NativePromiseContext.h) is a GC cell that carries one native ref across a promise reaction. A settle reaction `take()`s the pointer and derefs. If the promise is collected unsettled, the cell's destructor releases the ref on the next tick. - That destructor path was the only release the termination paths had. It needs a GC run, and at VM teardown it is skipped because a `RequestContext` deref is not sweep-safe. - `server.pendingRequests` counts contexts between creation and `deinit`, so each parked context kept it incremented. Related: #36567 (closed: its accounting special case is not needed with this change, and its scenarios are pinned here), #39660, #37513. <details><summary>Notes</summary> - At most one cell claim is outstanding per context: the handler promise cell is taken before the stream pump cell is created, the pump cell before the flush cell, and the flush or pump cell before the error-handler promise cell. `create_promise_cell` asserts this in debug builds. - The destructor clear runs inside GC sweep. It is a plain `Cell<JSValue>` write on the context, which the unreleased claim keeps alive (pool slots survive teardown for exactly this case, #37513). - The H3 early return in `on_abort` (stream destroyed after a successful `end()`) leaves the field alone: the promise settles normally there. - Repro from the issue: `pendingRequests` is now 0 right after the abort, with no `Bun.gc(true)`. - An earlier revision reclaimed in `on_abort` before `is_dead_request`. That dropped the claim's ref too early, `finalize_without_deinit` cleared the body stream ref without erroring it, and a parked `textStream()` read hung (body.test.ts "rejects when the client aborts mid-upload server-side"). The reclaim now runs after `end_request_streaming`. - A body consumed with `for await (req.body)` stays `Locked`, so `deinit` still rejects it through `end_request_streaming`. Only a `Used` body (`textStream()`) needs the sink-branch call. Tests cover both. - The upgrade case needs an async `server.upgrade()` while the handler promise parks with a reachable resolve. A sync upgrade has no cell, and a settled handler releases the claim through `take()`. - Pre-existing failures seen while running the suites (IPv6 requestIP, root range port, #6583, /bun:info loopback, bun-server source map on port 3000, abruptly closed upload, URL buffer leak under ASAN, two worker terminate tests, 8 websocket-server send timeouts) all reproduce on a baseline build without this diff. </details> <!-- robobun:evidence:begin --> --- **[review]** gate passed · iteration 0 · 4 files touched <details><summary>fails on main (without fix)</summary> ```console ASAN without fix: BUILD FAILED (no junit output) $ BUN_DEBUG_QUIET_LOGS=1 bun scripts/build.ts --profile=debug --quiet test "--reporter=junit" "--reporter-outfile=/tmp/mechgate.xml" test/js/bun/http/serve-pending-promise-abort-leak.test.ts ninja: Entering directory `/workspace/bun/build/debug' [1/177] gen ErrorCode+*.h [2/177] gen ProcessBindingHTTPParser.lut.h Generating /workspace/bun/build/debug/codegen/ProcessBindingHTTPParser.lut.h from /workspace/bun/src/jsc/bindings/ProcessBindingHTTPParser.cpp [3/177] gen JSEvent.lut.h Generating /workspace/bun/build/debug/codegen/JSEvent.lut.h from /workspace/bun/src/jsc/bindings/webcore/JSEvent.cpp [4/177] gen JSBuffer.lut.h Generating /workspace/bun/build/debug/codegen/JSBuffer.lut.h from /workspace/bun/src/jsc/bindings/JSBuffer.cpp [5/177] gen ProcessBindingConstants.lut.h Generating /workspace/bun/build/debug/codegen/ProcessBindingConstants.lut.h from /workspace/bun/src/jsc/bindings/ProcessBindingConstants.cpp [6/177] gen NodeModuleModule.lut.h Generating /workspace/bun/build/debug/codegen/NodeModuleModule.lut.h from /workspace/bun/src/jsc/modules/NodeModuleModule.cpp [7/177] gen BunProcess.lut.h Generating /workspace/bun/build/debug/codegen/BunProcess.lut.h from /wor ... (truncated) release without fix: 9 FAILED bun test v1.4.0-canary.1 (6e906e4) test/js/bun/http/serve-pending-promise-abort-leak.test.ts: (pass) RequestContext is freed when client aborts before Promise<Response> settles [71.60ms] (pass) Promise<Response> still works normally when not aborted [3.59ms] (pass) resolve() inside abort handler is handled safely [1.28ms] (pass) streaming 413 detaches the response so a late resolve/reject is a no-op [77.54ms] (pass) chunked request body consumed as a ReadableStream is capped at maxRequestBodySize [17.09ms] (fail) client abort frees the context even while the resolve function stays reachable [5001.80ms] ^ this test timed out after 5000ms. (fail) client abort while a direct stream pull() is parked frees the context and rejects a pending req.text() read [5000.75ms] ^ this test timed out after 5000ms. (fail) client abort while a direct stream pull() is parked frees the context and rejects a pending for await (req.body) read [5001.26ms] ^ this test timed out after 5000ms. (fail) client abort while a direct stream pull() is parked frees the context and rejects a pending req.textStream() read [5000.95ms] ^ this test timed out after 5000ms. (fail) pendingRequests ... (truncated) ``` </details> <details><summary>passes on PR (with fix)</summary> ```console ASAN with fix: all passed $ BUN_DEBUG_QUIET_LOGS=1 bun scripts/build.ts --profile=debug --quiet test "--reporter=junit" "--reporter-outfile=/tmp/mechgate.xml" test/js/bun/http/serve-pending-promise-abort-leak.test.ts bun test v1.4.0 (6e906e4) test/js/bun/http/serve-pending-promise-abort-leak.test.ts: (pass) RequestContext is freed when client aborts before Promise<Response> settles [3476.82ms] (pass) Promise<Response> still works normally when not aborted [62.73ms] (pass) resolve() inside abort handler is handled safely [62.86ms] (pass) streaming 413 detaches the response so a late resolve/reject is a no-op [10409.91ms] (pass) chunked request body consumed as a ReadableStream is capped at maxRequestBodySize [950.16ms] (pass) client abort frees the context even while the resolve function stays reachable [69.65ms] (pass) client abort while a direct stream pull() is parked frees the context and rejects a pending req.text() read [92.25ms] (pass) client abort while a direct stream pull() is parked frees the context and rejects a pending for await (req.body) read [74.05ms] (pass) client abort while a direct stream pull() is parked frees the context and rejects a pending req.textStream() read [6 ... (truncated) release with fix: all passed $ bun scripts/build.ts --profile=release [configured] bun-profile → bun (stripped) target linux-x64-gnu build type Release build dir ./build/release revision fa4a83e features baseline 23 deps, 120 codegen, 1172 objects in 1769ms ninja: Entering directory `/workspace/bun/build/release' [1/1235] gen bindgenv2 [2/1235] fetch tinycc [tinycc] up to date [3/1234] gen ErrorCode+*.h [4/1234] fetch zlib [zlib] up to date [5/1234] fetch libjpeg-turbo [libjpeg-turbo] up to date [6/1207] install /workspace/bun bun install v1.4.0-canary.1 (6e906e4) Checked 26 installs across 63 packages (no changes) [162.00ms] [7/1207] gen JSBuffer.lut.h Generating /workspace/bun/build/release/codegen/JSBuffer.lut.h from /workspace/bun/src/jsc/bindings/JSBuffer.cpp [8/1207] gen ProcessBindingConstants.lut.h Generating /workspace/bun/build/release/codegen/ProcessBindingConstants.lut.h from /workspace/bun/src/jsc/bindings/ProcessBindingConstants.cpp [9/1207] install /workspace/bun/packages/bun-error bun install v1.4.0-canary.1 (6e906e4) Checked 1 install across 2 packages (no changes) [7.00ms] [10/1207] subst deps/zlib/zlib.h [11/1207] fetch nodejs (prebui ... (truncated) ``` </details> <details><summary>diff hotspot</summary> ``` src/runtime/api/NativePromiseContext.rs | 36 +- src/runtime/server/RequestContext.rs | 84 ++++- src/runtime/server/server_body.rs | 4 + .../http/serve-pending-promise-abort-leak.test.ts | 403 +++++++++++++++++++-- 4 files changed, 487 insertions(+), 40 deletions(-) ``` </details> **gate history** · 9 passed · 0 rejected · iteration 0 <details><summary>evidence per changed file</summary> ``` file reads edits tests src/runtime/api/NativePromiseContext.rs 1 1 0 src/runtime/server/RequestContext.rs 12 17 0 src/runtime/server/server_body.rs 1 2 0 …st/js/bun/http/serve-pending-promise-abort-leak.test.ts 6 17 0 ``` </details> **root cause** · written by the author bot When a request handler or stream promise never settles, the NativePromiseContext cell created to observe it holds a reference on the request context, so an aborted request's context could only be torn down when GC collected the promise, and never at VM teardown since the deferred dereference is skipped during the sweep. This left aborted requests holding their pool slot, body, streams, sink, and a reference to the server indefinitely. The fix has the request context remember its outstanding promise cell and reclaim it, taking the cell's claim and dereferencing, on abort and every other term… <!-- robobun:evidence:end -->
…r req.clone() (#42017) ### Problem - A `Bun.serve` handler that calls `req.clone()` and reads neither body leaks about 7.3 KB per request, independent of body size. Full GC keeps it. - The root is the `protect()`ed pull promise of the request body's `ByteStream`. `end_request_streaming` (`src/runtime/server/RequestContext.rs`) reached that stream only through the body `Value`, and `clone()` re-points `Locked.readable` at a tee branch. It aborted that reader-less branch (a no-op) and returned before erroring the source the context holds in `request_body_readable_stream_ref`. `finalize_without_deinit` then dropped that ref silently. ### Fix - `end_request_streaming` rejects a `Locked` body as before, then errors and releases the `ByteStream` behind `request_body_readable_stream_ref` whenever that stream has not already ended. `finalize_without_deinit` leaves the ref to that call. - Correct because the context is the stream's only producer and nothing feeds it once request streaming ends. Erroring the source settles the parked pull and errors both branches, so a pending clone read rejects with the `AbortError` an un-cloned read already gets. - Self-reviewed: 2 concerns raised, 2 addressed (a guard so the non-clone paths do not deliver a second error, and a test for the client-abort path). - Verified: three new tests in `test/js/web/fetch/body-clone.test.ts` fail on 1.4.3 and with `src/` reverted, and pass with the fix. ### Background - `req.body`, `clone()` and `textStream()` wrap an incoming body in a native `ByteStream` source that the `RequestContext` feeds from the socket. - A pull with nothing buffered parks. Its promise stays `protect()`ed until the producer settles it, and it roots the whole tee. - `clone()` tees that stream and each branch pulls at once. A synchronous handler's response ends before uWS delivers the body bytes, and `detach_response` stops reading them. So only `end_request_streaming` can settle that pull. <details><summary>Notes</summary> - The `has_received_last_chunk` guard keeps the non-clone paths byte-identical. There, `to_error_instance` reaches the same `ByteStream` through the body `Value` and errors it first, and the context still holds its ref. `ByteStream::on_data` does tolerate a repeated `AbortReason` (the `done` arm returns early, a stored `Err` is a plain enum value), but the fix does not want to depend on that. - Repro from the report on release 1.4.3, 20k requests, `req.clone()` only: `4000:+40MB 8000:+69MB 12000:+97MB 16000:+123MB 20000:+149MB => ~7811 B/request`. `no-clone`, `clone-consume-clone` and `clone-consume-original` plateau. `heapStats()` per leaked request: +3 `ReadableStream`, +3 `ReadableStreamDefaultController`, +1 `ReadableStreamDefaultReader`, +1 `BytesInternalReadableStreamSource`, +1 `NativeStreamSourceAdapter`, +1 `ReadRequest`, +1 `StreamTeeState`, +1 `Uint8Array`, +3 `Promise`, +3 `FullPromiseReaction`; `protectedObjectTypeCounts`: +1 `Promise`, +1 `Uint8Array`. That graph is exactly what the protected pull promise reaches. - Why the body size does not matter: the response of a synchronous handler ends inside uWS's request callback, before uWS delivers the body bytes of the same packet, and `detach_response()` clears the body handler. The bytes are never buffered; only the tee machinery is retained. - `req.body.tee()` done by hand did not leak: the body `Value` still pointed at the native stream, so `to_error_instance` errored the `ByteStream` directly. Only the native clone paths (`Request.prototype.clone`, `BunRequest` clone, with or without `.body` observed first) re-point the body at a branch. The first new test covers all three. - Two tests pin the observable behaviour of a `clone().text()` started in the handler, for a body the client never sends: it rejects when the response ends first, and when the client disconnects while the handler is still parked. Before, both stayed pending forever. `req.text()` without a clone already rejects in both cases. - `finalize_without_deinit` is the first place that sees the held ref when `on_abort` takes the `is_dead_request()` shortcut with a `Used` (`textStream()`) body. Dropping the ref there left that read pending too; it now goes through the same erroring path thirty lines later. - The fetch client's `Response.clone()` with nothing read does not leak (checked separately, 500 iterations, zero retained streams). - Suites run on the debug ASAN build: `test/js/web/fetch/body-clone.test.ts` (65 pass), `test/js/bun/http/serve-body-leak.test.ts` (15 pass, HTTP/1 and HTTP/2), `test/js/bun/http/serve.test.ts` (295 pass; 2 failures that also fail on the release binary in this container: root port range, `/bun:info` loopback), `serve-http2-lifecycle.test.ts`, `serve-pending-promise-abort-leak.test.ts`, `bun-serve-routes.test.ts`, `bun-serve-body-json-async.test.ts`, `test/js/web/fetch/body.test.ts`, `body-stream.test.ts`, `body-mixin-errors.test.ts`, `wpt/textstream-wpt.test.ts`, `fetch-abort-stream-body.test.ts`. - Related open PRs that touch the same function but not this bug: #33524 (keep delivering a late body after the response), #39660 (release the body slot once complete). </details> <!-- robobun:evidence:begin --> --- **[human-review]** gate passed · iteration 1 · 2 files touched <details><summary>fails on main (without fix)</summary> ```console ASAN without fix: BUILD FAILED (no junit output) $ BUN_DEBUG_QUIET_LOGS=1 bun scripts/build.ts --profile=debug --quiet test "--reporter=junit" "--reporter-outfile=/tmp/pr_gate.xml" test/js/web/fetch/body-clone.test.ts ninja: Entering directory `/workspace/bun/build/debug' [1/162] gen generated_host_exports.rs generated_host_exports.rs: 122 exports (host=5, lazy=10, generic=107, rust=0); 242 extern-C blocks audited [2/162] gen cpp.rs (cppbind) [2/162] cargo bun_runtime → libbun_runtime.a FAILED: rust-target/x86_64-unknown-linux-gnu/debug/libbun_runtime.a /workspace/bun/build/release/bun /workspace/bun/scripts/build/stream.ts rust --console --cwd=/workspace/bun --env=CARGO_TERM_COLOR=always --env=BUN_CODEGEN_DIR=/workspace/bun/build/debug/codegen --env=CC=/usr/lib/llvm-21/bin/clang --env=CXX=/usr/lib/llvm-21/bin/clang++ --env=AR=/usr/lib/llvm-21/bin/llvm-ar --env=CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER=/usr/lib/llvm-21/bin/clang++ --env=CARGO_HOME=/root/.cargo --env=RUSTUP_HOME=/root/.rustup --env=RUSTUP_TOOLCHAIN=nightly-2026-07-20 --env=CARGO_PROFILE_RELEASE_LTO=off --env=CARGO_PROFILE_RELEASE_CODEGEN_UNITS=16 --env=CARGO_PROFILE_RELEASE_DEBUG_ASSERTIONS=true --env=CARGO_ENCODED_RUSTFLAGS='-Crelocation-mod ... (truncated) release without fix: all passed bun test v1.4.3-canary.1 (427e0a0) test/js/web/fetch/body-clone.test.ts: (pass) Request with streaming body can be cloned [0.30ms] (pass) Response with streaming body can be cloned [0.15ms] (pass) Request with large streaming body can be cloned [5.63ms] (pass) Request with large streaming body can be cloned (pull) [4.43ms] (pass) Response with chunked streaming body can be cloned [30.88ms] (pass) Request with streaming body can be cloned multiple times [0.33ms] (pass) Request with string body can be cloned [0.11ms] (pass) Response with string body can be cloned [0.07ms] (pass) Request with ArrayBuffer body can be cloned [0.15ms] (pass) Response with ArrayBuffer body can be cloned [0.09ms] (pass) Request with Uint8Array body can be cloned [0.11ms] (pass) Response with Uint8Array body can be cloned [0.07ms] (pass) Request with mixed body types can be cloned [0.30ms] (pass) Response with mixed body types can be cloned [0.21ms] (pass) Request with non-ASCII string body can be cloned [0.10ms] (pass) Response with non-ASCII string body can be cloned [0.06ms] (pass) Request with streaming non-ASCII body can be cloned [0.12ms] (pass) Response with streaming non-ASCII bod ... (truncated) ``` </details> <details><summary>passes on PR (with fix)</summary> ```console ASAN with fix: all passed $ BUN_DEBUG_QUIET_LOGS=1 bun scripts/build.ts --profile=debug --quiet test "--reporter=junit" "--reporter-outfile=/tmp/pr_gate.xml" test/js/web/fetch/body-clone.test.ts bun test v1.4.3 (f42e980) test/js/web/fetch/body-clone.test.ts: (pass) Request with streaming body can be cloned [37.67ms] (pass) Response with streaming body can be cloned [12.72ms] (pass) Request with large streaming body can be cloned [25.39ms] (pass) Request with large streaming body can be cloned (pull) [32.80ms] (pass) Response with chunked streaming body can be cloned [51.79ms] (pass) Request with streaming body can be cloned multiple times [14.25ms] (pass) Request with string body can be cloned [8.76ms] (pass) Response with string body can be cloned [7.99ms] (pass) Request with ArrayBuffer body can be cloned [11.92ms] (pass) Response with ArrayBuffer body can be cloned [9.39ms] (pass) Request with Uint8Array body can be cloned [9.30ms] (pass) Response with Uint8Array body can be cloned [8.50ms] (pass) Request with mixed body types can be cloned [22.29ms] (pass) Response with mixed body types can be cloned [20.63ms] (pass) Request with non-ASCII string body can be cloned [7.49ms] (pass) Res ... (truncated) release with fix: all passed $ bun scripts/build.ts --profile=release [configured] bun-profile → bun (stripped) in 812ms (unchanged) ninja: Entering directory `/workspace/bun/build/release' [1/123] gen generated_host_exports.rs generated_host_exports.rs: 122 exports (host=5, lazy=10, generic=107, rust=0); 242 extern-C blocks audited [2/123] gen cpp.rs (cppbind) [2/123] cargo bun_runtime → libbun_runtime.a �[1m�[92m Compiling�[0m bun_core v0.0.0 (/workspace/bun/src/bun_core) �[1m�[92m Compiling�[0m bun_errno v0.0.0 (/workspace/bun/src/errno) �[1m�[92m Compiling�[0m bun_ptr v0.0.0 (/workspace/bun/src/ptr) �[1m�[92m Compiling�[0m bun_boringssl_sys v0.0.0 (/workspace/bun/src/boringssl_sys) �[1m�[92m Compiling�[0m bun_safety v0.0.0 (/workspace/bun/src/safety) �[1m�[92m Compiling�[0m bun_base64 v0.0.0 (/workspace/bun/src/base64) �[1m�[92m Compiling�[0m bun_cares_sys v0.0.0 (/workspace/bun/src/cares_sys) �[1m�[92m Compiling�[0m bun_zlib_sys v0.0.0 (/workspace/bun/src/zlib_sys) �[1m�[92m Compiling�[0m bun_zstd v0.0.0 (/workspace/bun/src/zstd) �[1m�[92m Compiling�[0m bun_picohttp v0.0.0 (/workspace/bun/src/picohttp) �[1m�[92m Compiling�[0m bun_brotli v0.0.0 (/workspace/bun/src/ ... (truncated) ``` </details> <details><summary>diff hotspot</summary> ``` src/runtime/server/RequestContext.rs | 49 ++++++------ test/js/web/fetch/body-clone.test.ts | 141 +++++++++++++++++++++++++++++++++++ 2 files changed, 164 insertions(+), 26 deletions(-) ``` </details> **gate history** · 2 passed · 0 rejected · iteration 1 <details><summary>evidence per changed file</summary> ``` file reads edits tests src/runtime/server/RequestContext.rs 9 5 19 test/js/web/fetch/body-clone.test.ts 6 6 19 ``` </details> <!-- robobun:evidence:end -->
…er a streamed response (#42844) ### Problem - Over HTTP/2 and HTTP/3, a streamed response that the sink ends from the writable callback never releases its `RequestContext`. `pendingRequests` stays up and a graceful `stop()` hangs. - A client controls how often. On one h2c connection with a 4-byte initial window, 200 of 200 requests leak, and they outlive the connection. - `on_abort` (`RequestContext.rs:1468`) sees `has_responded()` and only drops `resp`. The body stream's reaction then finds no `resp`, so nothing releases the base ref. ### Fix - `on_abort` now ends the request there, through `end_already_responded_stream()`: the HTTP/1 path for a response the sink ended. That branch can reject a parked request-body read, so the event loop scope now covers both arms. - Correct because every other path that clears `resp` also releases the base ref. The late reaction finds the request ended, and no-ops. - Verified: 9 new cases in `serve-http3.test.ts` and `serve-http2.test.ts` fail on main, pass here. Other suites: Notes. - Self-reviewed: 17 concerns raised, 16 addressed. The last is a follow-up, named in Notes. ### Background - A `RequestContext` holds a base ref while `resp` is set. Each end path clears `resp` and releases it. - The sink (`HTTPServerWritable`) writes a streamed body and can end the uWS response itself, for example once flow control reopens. The context hears of that from the stream's reaction. - HTTP/2 and HTTP/3 free a stream once both sides finish. uWS reports that through `onAborted`, also after a complete response. It is the last call on `resp`. <details><summary>Notes</summary> - The ASAN lane's signature for this is `Direct leak of 15 byte(s)` from `RequestContext::on_buffered_body_chunk` (`RequestContext.rs:4249`). - Found by the ASAN lane in build 115959 on `test/js/bun/http/serve-http3.test.ts`: all tests pass, then LeakSanitizer reports the buffered request body (`request-content`, 15 bytes). The pool slot of the context is not visible to LeakSanitizer. Only the buffered body bytes are, so the report needs a request body. The leak itself does not: a plain GET leaks the context too. - Every streamed body shape leaks: a `ReadableStream`, a direct `ReadableStream`, and an async generator. A string body does not use the sink and does not leak (checked on main). - The leak reproduces on the release build. Script: `Bun.serve({ tls, http3: true, fetch: () => new Response(new ReadableStream({ async pull(c) { c.enqueue(bytes); c.close(); } })) })`, one `fetch(..., { protocol: "http3" })`, then read `server.pendingRequests`. Before: 1, and `await server.stop()` hangs. After: 0, and `stop()` resolves in a few ms. - The ordering a reviewer would want checked is the nested one: `on_abort` firing while `do_render_stream` is still on the stack. `server.stop(true)` inside `pull()` after the sink ended the response drives it. The debug log shows `doRenderStream -> onAbort -> endAlreadyRespondedStream -> aborted while attaching the stream -> deinit`, so the arm ends the request, `discard_stream_after_abort` cleans up the sink the arm left behind, and the context is freed only after the outer frame unwinds. Clean under ASAN, and a late `controller.write()` after the teardown still fails with the normal closed-sink error. It leaks on main (`pendingRequests` 1) and is the ninth new case. - `wrapper.sink.res = None` in that arm: the sink outlives the call on this path and its `finalize()` reads `res` unless the sink is done. I could not build a case that dereferences the freed handle, because the JS wrapper rejects a call on a closed controller first, and removing the line changed nothing under ASAN. It is kept because it matches what the sink's own `abort()` does (`streams.rs:1974`) and keeps the guard local instead of resting on a cross-file invariant. - Measured amplification, one h2c connection, client-chosen 4-byte initial window, N=200 sequential requests: on the pre-fix binary `pendingRequests` 200, 201 `Response` objects retained after `Bun.gc(true)`, still 200 after the socket closes, graceful `stop()` hangs. On this branch: 0, 1, 0, and `stop()` resolves. `http2` and `http3` both default to false, so only a server that opts in is affected. - A stress run (10 body shapes, 160 requests on one H3 server, client aborts mixed in) leaves `pendingRequests` at 64 on main and at 0 with this change. It is clean under ASAN. - Follow-ups this PR deliberately leaves out, so it stays at the one-line lifetime fix: a notification from the sink to its context when it ends a response (that is what would also fix the HTTP/1 twin above), a re-entrancy guard in `EventLoop::drain_microtasks_with_global` of the kind already in `VirtualMachine.rs`, and the drain-ordering question in the same helper. The last two are helper-wide and already reachable on main over HTTP/1. - Relation to #39660 (open): that PR releases the context's ref on the request body slot after the last chunk. In this repro the last chunk arrives (`onBufferedBodyChunk 0 true`), so with #39660 the 15 bytes are freed and LeakSanitizer goes quiet. The `RequestContext` still leaks and `server.stop()` still hangs. The two changes do not overlap. The new tests assert on `server.pendingRequests` and `server.stop()`, so they fail on main with or without #39660. - Audit of the rule "a path that clears `resp` also releases the base ref". Four sites clear `resp` on main. `detach_response()`: each of its 12 callers ends in `deref()` or `RequestContextRef::adopt`, or is `deinit` at refcount 0. `end_already_responded_stream()`: `take()`, then `deref()`. The WebSocket upgrade (`server_body.rs:2012`): `set(None)`, then `reclaim_promise_cell()` and `deref()`. The `has_responded()` branch of `on_abort` (`RequestContext.rs:1471` on main): `set(None)`, then `return`. It was the one exception. `discard_stream_after_abort` already relies on the rule. - Why not fix the reaction (`handle_resolve_stream`): when the pump promise never settles it never runs. A direct stream whose `pull()` awaits forever after an asynchronous `controller.end()` leaks on main and is fixed here for H2/H3 (the last two new cases). The end has to come from a later microtask: an end inside the first `pull()` leaves the response already finished when the stream is attached, which takes a different path and does not leak. - HTTP/1 has the same never-settling shape and still leaks it after this change (3 requests, `pendingRequests` 1, 2, 3, graceful `stop()` hangs, measured on this branch). An HTTP/1 socket is not freed per request, so there is no equivalent notification to hook. That needs the sink to tell its context when it ends a response, which is a larger change and a follow-up. - lsquic debug log for the first response: `qenc-hdl: not all 0 bytes of encoder stream written out; 1 bytes buffered`, `stream: stashed 49 bytes of header block`, `stream: still sending headers: no writing allowed`. The next write pass sends the block and calls the writable callback, where the sink ends the response. `service_streams` then calls `on_close` in the same `process_conns`. A handler that answers from a timer writes directly, so it does not hit this. A second request on a warm connection does not hit it either. - HTTP/2: `Http2Response::tryEnd` returns false when the stream window is too small. The sink then finishes from `onWritable`, reached from `epilogue -> pump -> drainWritable` in the socket event that carried the WINDOW_UPDATE. `sweepConnection` in the same epilogue calls `onAborted`. The new test drives this with the raw frame client: `SETTINGS_INITIAL_WINDOW_SIZE = 4`, then one `WINDOW_UPDATE`. - The order inside one microtask checkpoint is: JS microtasks, then the deferred tasks (HTTP/2 sweep), then `drain_quic_if_necessary` (HTTP/3). So a response that the sink ends from JS is always detached by the reaction first. Only an end from a native callback loses the race. - `wrapper.sink.res = None`: the sink keeps a raw copy of `resp`. If a frame up the stack keeps the context alive, the sink survives this call, and `HTTPServerWritable::start()` reads `res` without a `done` check. The abort path clears it for the same reason. - Behaviour that does not change: `req.signal` does not fire for a stream that closes after a complete response. A rejection of the body stream that arrives after the stream closed is still not reported on HTTP/2 and HTTP/3. - Suites run on the debug ASAN build: `serve-http3` (69), `serve-http2` (91), `serve-http2-lifecycle` (23), `serve-http2-protocol` (201), `serve-protocols`, `fetch-http3-client`, `fetch-http3-cold-post`, `fetch-http3-adversarial`, `serve-direct-readable-stream`, `serve-async-stream-client-abort`, `serve-pending-promise-abort-leak`, `serve-response-gc-backpressure-abort`, `serve-response-stream-sink-leak`, `serve-stream-reject-flush-leak`, `serve-stream-body-error`, `serve-error-handler-stream`, `async-iterator-stream`. The new cases also pass with `detect_leaks=1` and the CI LeakSanitizer options. </details> <!-- robobun:evidence:begin --> --- **[human-review]** gate passed · iteration 0 · 5 files touched <details><summary>fails on main (without fix)</summary> ```console ASAN without fix: 10 FAILED $ BUN_DEBUG_QUIET_LOGS=1 bun scripts/build.ts --profile=debug --quiet test "--reporter=junit" "--reporter-outfile=/tmp/pr_gate.xml" "test/js/bun/http/serve-http2.test.ts" "test/js/bun/http/serve-http3.test.ts" bun test v1.4.3 (09bb546) test/js/bun/http/serve-http3.test.ts: (node:345180) ExperimentalWarning: quic is an experimental feature and might change at any time (Use `bun-debug --trace-warnings ...` to show where the warning was created) (pass) Bun.serve HTTP/3 > basic GET [2287.19ms] (pass) Bun.serve HTTP/3 > POST echoes body, status, request headers [2254.51ms] (pass) Bun.serve HTTP/3 > 204 with no body [2126.77ms] (pass) Bun.serve HTTP/3 > query string is preserved [2514.46ms] (pass) Bun.serve HTTP/3 > large response body crosses multiple QUIC packets [2436.10ms] (pass) Bun.serve HTTP/3 > concurrent requests across separate connections [2207.70ms] (pass) Bun.serve HTTP/3 > client abort mid-response does not crash the server [2266.73ms] (pass) Bun.serve HTTP/3 > http1: false rejects HTTP/1.1 but accepts HTTP/3 [2128.81ms] (pass) Bun.serve HTTP/3 > http1: false — url/address/stop see the QUIC listener [3110.49ms] (pass) Bun.serve HTTP/3 > maxRequestBodySi ... (truncated) release without fix: 1 skipped bun test v1.4.3-canary.1 (528df8e) test/js/bun/http/serve-http3.test.ts: (node:346139) ExperimentalWarning: quic is an experimental feature and might change at any time (Use `bun --trace-warnings ...` to show where the warning was created) (pass) Bun.serve HTTP/3 > basic GET [150.61ms] (pass) Bun.serve HTTP/3 > POST echoes body, status, request headers [145.86ms] (pass) Bun.serve HTTP/3 > 204 with no body [158.35ms] (pass) Bun.serve HTTP/3 > query string is preserved [147.33ms] (pass) Bun.serve HTTP/3 > large response body crosses multiple QUIC packets [147.97ms] (pass) Bun.serve HTTP/3 > concurrent requests across separate connections [143.88ms] (pass) Bun.serve HTTP/3 > client abort mid-response does not crash the server [146.63ms] (pass) Bun.serve HTTP/3 > http1: false rejects HTTP/1.1 but accepts HTTP/3 [146.71ms] (pass) Bun.serve HTTP/3 > http1: false — url/address/stop see the QUIC listener [1038.10ms] (pass) Bun.serve HTTP/3 > maxRequestBodySize is enforced for H3 bodies without Content-Length [139.51ms] (pass) Bun.serve HTTP/3 > unknown route returns 404 [146.13ms] (pass) Bun.serve HTTP/3 > routes: handler with :params [142.65ms] (pass) Bun.serve HTTP/3 ... (truncated) ``` </details> <details><summary>passes on PR (with fix)</summary> ```console ASAN with fix: all passed $ BUN_DEBUG_QUIET_LOGS=1 bun scripts/build.ts --profile=debug --quiet test "--reporter=junit" "--reporter-outfile=/tmp/pr_gate.xml" "test/js/bun/http/serve-http2.test.ts" "test/js/bun/http/serve-http3.test.ts" bun test v1.4.3 (09bb546) test/js/bun/http/serve-http3.test.ts: (node:353218) ExperimentalWarning: quic is an experimental feature and might change at any time (Use `bun-debug --trace-warnings ...` to show where the warning was created) (pass) Bun.serve HTTP/3 > basic GET [2242.48ms] (pass) Bun.serve HTTP/3 > POST echoes body, status, request headers [1711.32ms] (pass) Bun.serve HTTP/3 > 204 with no body [1870.53ms] (pass) Bun.serve HTTP/3 > query string is preserved [2143.11ms] (pass) Bun.serve HTTP/3 > large response body crosses multiple QUIC packets [2078.85ms] (pass) Bun.serve HTTP/3 > concurrent requests across separate connections [2294.95ms] (pass) Bun.serve HTTP/3 > client abort mid-response does not crash the server [2178.72ms] (pass) Bun.serve HTTP/3 > http1: false rejects HTTP/1.1 but accepts HTTP/3 [2015.41ms] (pass) Bun.serve HTTP/3 > http1: false — url/address/stop see the QUIC listener [3020.29ms] (pass) Bun.serve HTTP/3 > maxRequestBodySi ... (truncated) release with fix: 1 skipped $ bun scripts/build.ts --profile=release [configured] bun-profile → bun (stripped) in 944ms (unchanged) ninja: Entering directory `/workspace/bun/build/release' [1/133] esbuild bun-error ../../build/release/codegen/bun-error/index.js 34.9kb ../../build/release/codegen/bun-error/bun-error.css 12.8kb ⚡ Done in 23ms [2/133] gen ErrorCode+*.h [3/133] gen compressed/codegen/bun-error/index.js.zst [4/133] gen compressed/codegen/bun-error/bun-error.css.zst [5/133] gen NodeModuleModule.lut.h Generating /workspace/bun/build/release/codegen/NodeModuleModule.lut.h from /workspace/bun/src/jsc/modules/NodeModuleModule.cpp [6/133] gen generated_host_exports.rs generated_host_exports.rs: 122 exports (host=5, lazy=10, generic=107, rust=0); 243 extern-C blocks audited [7/133] gen ZigGeneratedClasses.{cpp,h,rs} Found 2 classes from /workspace/bun/src/jsc/resolve_message.classes.ts - ResolveMessage (15 fields) - BuildMessage (10 fields) Found 1 classes from /workspace/bun/src/runtime/api/Archive.classes.ts - Archive (4 fields, 1 class fields) Found 2 classes from /workspace/bun/src/runtime/api/BunObject.classes.ts - ResourceUsage (8 fields) - Subprocess (20 ... (truncated) ``` </details> <details><summary>diff hotspot</summary> ``` packages/bun-uws/src/Http3Context.h | 5 +- src/runtime/server/RequestContext.rs | 56 ++++++++--------- src/runtime/webcore/streams.rs | 16 +++-- test/js/bun/http/serve-http2.test.ts | 116 +++++++++++++++++++++++++++++++++++ test/js/bun/http/serve-http3.test.ts | 82 +++++++++++++++++++++++++ 5 files changed, 234 insertions(+), 41 deletions(-) ``` </details> **gate history** · 1 passed · 0 rejected · iteration 0 <details><summary>evidence per changed file</summary> ``` file reads edits tests packages/bun-uws/src/Http3Context.h 2 1 25 src/runtime/server/RequestContext.rs 13 9 26 src/runtime/webcore/streams.rs 4 2 25 test/js/bun/http/serve-http2.test.ts 1 4 15 test/js/bun/http/serve-http3.test.ts 6 6 17 ``` </details> <!-- robobun:evidence:end -->
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Problem
pull()) leaks its buffered body. LSan:16 byte(s) leaked in 1 allocation(s)fromRequestContext::on_buffered_body_chunk(RequestContext.rs:4115), after a client abort or at VM teardown.deinit(RequestContext.rs:889). The promise pins the context, sodeinitwaits for GC, and at VM teardown it never runs (NativePromiseContext.rs:204). Bun.serve: an aborted request whose handler or pull() promise never settles is torn down only by GC, never at VM teardown #39739 tracks the rest of what such a context keeps.end_request_streamingreject aLockedvalue thatrequest.bodyhad created over a complete body. Read after the response, it gave""orThe connection was closed.Fix
on_buffered_body_chunkreleases the context's ref right after it stores and resolves the last chunk, as its streaming arm already does (RequestContext.rs:4042). A body that never completes is still released indeinit.Requestholds its own ref, so the bytes live exactly as long as theRequest.test/js/bun/http/serve-body-leak.test.ts. Four LSan cells (abort, parkedpull(), terminated Worker,Requestcollected before the last chunk) and two body reads fail on main. One ASAN cell pins that the read is resolved before the slot is dropped.Background
body_value_pool. TheRequestContextand the JSRequesthold one ref each. VM teardown frees the pool without dropping occupied slots (jsc_hooks.rs:95).NativePromiseContextcell. Only GC of the cell releases it. VM teardown does not deref the context: unsafe during the sweep.request.bodyon a complete body replaces the stored bytes with aLockedvalue over a stream of them.end_request_streaming, run by every end path, rejects aLockedvalue in a slot the context still holds.Notes
BUN_DESTRUCT_VM_ON_EXIT=1 ASAN_OPTIONS=detect_leaks=1 LSAN_OPTIONS=suppressions=test/leaksan.supp: leaks every run on the unfixed debug build, clean with this change. The LSan cells fail on main atRequestContext.rs:4115. TheRequestwrapper is destroyed at teardown and drops its ref, so with this change the slot count reaches zero and the bytes are freed.is_dead_requestonly tests forLockedand toleratesNone.end_request_streaminganddeinittolerateNone.on_start_bufferingis reachable only through theLockedvalue created at prepare time, whichresolveconsumes here.Body::Value::resolvehands the bytes to its consumer synchronously, so the release right after it is safe. The context is pinned for the callback, so the release is safe when it is the slot's last ref too. The two collected-Requestcells exercise that case.end_request_streaming. Review showed that no test can observe that: such a slot holds no allocation of its own, and a slot past the inline pool stays reachable through the parked context, so LSan does not report it either. It is the same class as the other resources a parked context keeps, so it is left to Bun.serve: an aborted request whose handler or pull() promise never settles is torn down only by GC, never at VM teardown #39739, and this PR is reduced to the one release that the failing cells need.setImmediateinside the handler. When it reported synchronously,terminate()sometimes reached the worker beforeon_responsesubscribed to the promise.drain_microtasksthen returnsStopped, the context keeps a single ref, andon_abortfrees it on the spot, so that request never reached the leaking state. The body read cells use the same hop to let a small body be stored without consuming it: it arrives in the same packet as the headers. The collected-Requestcells send the upload by hand and keep the handler promise reachable, so thatBun.gccollects theRequest(aFinalizationRegistryproves it) but not the promise.serve-body-leak.test.ts(whole file),test/js/web/fetch/body*.test.ts(6 files),serve-pending-promise-abort-leak,bun-serve-body-json-async,serve-async-stream-client-abort,serve-request-extra-memory,http-server-chunking,bun-serve-static-stress-access-body,serve.test.ts,bun-server.test.ts,proxy.test.ts,proxy.test.js. The last four have a fewlocalhostand proxy env failures in this container that also occur with the released binary.no test proof · iteration 0 · Platform-specific test(s) that do not run on this machine. Deferring to CI, which covers all platforms: test/js/bun/http/serve-body-leak.test.ts