fix(minifier): keep Object introspection calls on a possible Proxy by Dunqing · Pull Request #23483 · oxc-project/oxc

Dunqing · 2026-06-16T08:38:02Z

Summary

Object.keys, getOwnPropertyDescriptor(s), getOwnPropertyNames, getOwnPropertySymbols, getPrototypeOf, hasOwn, isExtensible, isFrozen, and isSealed introspect their target through internal methods a Proxy can trap ([[OwnPropertyKeys]], [[GetOwnProperty]], …), so they have observable side effects when the target is a Proxy. They were treated as unconditionally pure and dropped when unused — so Object.getOwnPropertyDescriptor(proxy, "foo") / Object.keys(proxy) were silently removed, skipping the trap.

They are now treated as side-effect-free only when the target is provably not a Proxy (a determined, non-null value type — i.e. a literal), unless the bundler opts out of property-read side effects. A null/undefined/missing target is also kept (it throws a TypeError).

Object.create(proto) is pure only with an object/null prototype and no properties argument (read via [[OwnPropertyKeys]]/[[Get]]).
Object.values/entries are no longer treated as pure at all — they invoke [[Get]] and run getters even on a plain object.
Object.is stays unconditionally pure.

Credit

Adapted from #21056 by @gthb. Their proxy_sensitive_arg_index approach is preserved; this version adds corrections for the getter-invoking methods (values/entries, and create with properties) and the throw-on-null/undefined cases that the original treated as droppable.

Verified by cargo test -p oxc_minifier / -p oxc_ecmascript; minsize unchanged.

cloese #21056

Dunqing · 2026-06-16T08:38:18Z

fix(minifier): keep Object introspection calls on a possible Proxy #23483 👈 (View in Graphite)
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codspeed-hq · 2026-06-16T08:47:12Z

Merging this PR will not alter performance

✅ 62 untouched benchmarks
⏩ 9 skipped benchmarks¹

_{Comparing fix/minifier-proxy-sensitive-object-methods (ccea0ac) with main (1a40b71)}

9 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

oxc-guard · 2026-06-16T09:53:01Z

Monitor Oxc

Commit: d30cfba376da

suite	result
Build	✅
Isolated Declarations	✅
(transformer)	❌
(formatter_dcr)	✅
(codegen)	✅
(formatter)	❌
(dce)	✅
(compressor)	✅
(mangler)	❌
(whitespace)	✅

Dunqing · 2026-06-17T08:06:57Z

Merge activity

Jun 17, 8:06 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Jun 17, 8:07 AM UTC: Dunqing added this pull request to the Graphite merge queue.
Jun 17, 8:13 AM UTC: Merged by the Graphite merge queue.

Dunqing · 2026-06-17T08:07:23Z

Feel free to review after merging.

@gthb

…23483) ## Summary Closes #17157. `Object.keys`, `getOwnPropertyDescriptor(s)`, `getOwnPropertyNames`, `getOwnPropertySymbols`, `getPrototypeOf`, `hasOwn`, `isExtensible`, `isFrozen`, and `isSealed` introspect their target through internal methods a `Proxy` can trap (`[[OwnPropertyKeys]]`, `[[GetOwnProperty]]`, …), so they have observable side effects when the target is a Proxy. They were treated as unconditionally pure and dropped when unused — so `Object.getOwnPropertyDescriptor(proxy, "foo")` / `Object.keys(proxy)` were silently removed, skipping the trap. They are now treated as side-effect-free only when the target is provably not a Proxy (a determined, non-null value type — i.e. a literal), unless the bundler opts out of property-read side effects. A `null`/`undefined`/missing target is also kept (it throws a `TypeError`). - `Object.create(proto)` is pure only with an object/`null` prototype and no `properties` argument (read via `[[OwnPropertyKeys]]`/`[[Get]]`). - `Object.values`/`entries` are no longer treated as pure at all — they invoke `[[Get]]` and run getters even on a plain object. - `Object.is` stays unconditionally pure. ## Credit Adapted from #21056 by @gthb. Their `proxy_sensitive_arg_index` approach is preserved; this version adds corrections for the getter-invoking methods (`values`/`entries`, and `create` with properties) and the throw-on-`null`/`undefined` cases that the original treated as droppable. Verified by `cargo test -p oxc_minifier` / `-p oxc_ecmascript`; `minsize` unchanged. cloese #21056

### 💥 BREAKING CHANGES - 7a76cd3 estree: [**BREAKING**] Make whether to include TS fields a runtime option (#23574) (overlookmotel) - e7b6b68 estree: [**BREAKING**] `ESTree` config use methods not consts (#23573) (overlookmotel) ### 🚀 Features - 556cc6d data_structures: Add `CodeBuffer::as_str` method (#23571) (overlookmotel) - 38c4b06 parser: Add friendly error for adjacent JSX elements (#23378) (sapphi-red) - 53509a8 minifier: Treeshake pure typed arrays and Set/Map array literals (#23469) (Dunqing) - 09762d9 minifier: Inline const value for read-only vars (#22593) (Dunqing) ### 🐛 Bug Fixes - 20375f9 react_compiler: Keep imports referenced only by a computed key (#23586) (Boshen) - 31bfd9b minifier: Keep Object introspection calls on a possible Proxy (#23483) (Dunqing) - 837a395 parser: Treat a line comment after ':' as leading, not trailing (#23515) (Dunqing) - e409fe0 minifier: Keep `new Map`/`WeakSet`/`WeakMap` with a string argument (#23470) (Dunqing) - ae02b4e ci/parser: Use `minimal` for vitest reporter (#23457) (camc314) ### ⚡ Performance - cf24329 mangler: Compile slot sort once instead of per CAPACITY (#23577) (Boshen) - 4058a6a parser: Reduce code bloat from verify_modifiers monomorphization (#23576) (Boshen) - 053b0c1 estree: Remove pointless `mem::take` (#23572) (overlookmotel) - dfb52b6 transformer: Pre-size statement vecs in TS enum & namespace lowering (#23516) (Yunfei He) - 970e09a minifier: Compute template-literal inline checks in a single pass (#23467) (Yunfei He) - 3170c0e semantic,mangler,minifier: Fix `Semantic::stats` node count and reuse stats in mangler builds (#23352) (Boshen) - d1fa6e0 minifier: Evaluate ternary branches once in minimize_conditional_expression (#23479) (Yunfei He) - 3fa8051 transformer: Pre-size JSX props vec to attribute count (#23466) (Yunfei He) - 488b382 react_compiler: Borrow binding names in prefilter instead of allocating (#23471) (Yunfei He) - bcb3894 minifier: Incremental scoping refresh, delete LiveUsageCollector (#23197) (Dunqing) ### 📚 Documentation - f68641e data_structures: Improve docs on safety contract (#23575) (overlookmotel) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>

sapphi-red · 2026-06-18T11:55:06Z

+    test("Object.isExtensible()", true);
+    test("Object.isFrozen()", true);
+    test("Object.isSealed()", true);


Suggested change

test("Object.isExtensible()", true);

test("Object.isFrozen()", true);

test("Object.isSealed()", true);

test("Object.isExtensible()", false);

test("Object.isFrozen()", false);

test("Object.isSealed()", false);

These does not throw an error if the argument is not an object.
https://tc39.es/ecma262/#sec-object.isextensible

@gthb

…23483) ## Summary Closes #17157. `Object.keys`, `getOwnPropertyDescriptor(s)`, `getOwnPropertyNames`, `getOwnPropertySymbols`, `getPrototypeOf`, `hasOwn`, `isExtensible`, `isFrozen`, and `isSealed` introspect their target through internal methods a `Proxy` can trap (`[[OwnPropertyKeys]]`, `[[GetOwnProperty]]`, …), so they have observable side effects when the target is a Proxy. They were treated as unconditionally pure and dropped when unused — so `Object.getOwnPropertyDescriptor(proxy, "foo")` / `Object.keys(proxy)` were silently removed, skipping the trap. They are now treated as side-effect-free only when the target is provably not a Proxy (a determined, non-null value type — i.e. a literal), unless the bundler opts out of property-read side effects. A `null`/`undefined`/missing target is also kept (it throws a `TypeError`). - `Object.create(proto)` is pure only with an object/`null` prototype and no `properties` argument (read via `[[OwnPropertyKeys]]`/`[[Get]]`). - `Object.values`/`entries` are no longer treated as pure at all — they invoke `[[Get]]` and run getters even on a plain object. - `Object.is` stays unconditionally pure. ## Credit Adapted from #21056 by @gthb. Their `proxy_sensitive_arg_index` approach is preserved; this version adds corrections for the getter-invoking methods (`values`/`entries`, and `create` with properties) and the throw-on-`null`/`undefined` cases that the original treated as droppable. Verified by `cargo test -p oxc_minifier` / `-p oxc_ecmascript`; `minsize` unchanged. cloese #21056

### 💥 BREAKING CHANGES - 7a76cd3 estree: [**BREAKING**] Make whether to include TS fields a runtime option (#23574) (overlookmotel) - e7b6b68 estree: [**BREAKING**] `ESTree` config use methods not consts (#23573) (overlookmotel) ### 🚀 Features - 556cc6d data_structures: Add `CodeBuffer::as_str` method (#23571) (overlookmotel) - 38c4b06 parser: Add friendly error for adjacent JSX elements (#23378) (sapphi-red) - 53509a8 minifier: Treeshake pure typed arrays and Set/Map array literals (#23469) (Dunqing) - 09762d9 minifier: Inline const value for read-only vars (#22593) (Dunqing) ### 🐛 Bug Fixes - 20375f9 react_compiler: Keep imports referenced only by a computed key (#23586) (Boshen) - 31bfd9b minifier: Keep Object introspection calls on a possible Proxy (#23483) (Dunqing) - 837a395 parser: Treat a line comment after ':' as leading, not trailing (#23515) (Dunqing) - e409fe0 minifier: Keep `new Map`/`WeakSet`/`WeakMap` with a string argument (#23470) (Dunqing) - ae02b4e ci/parser: Use `minimal` for vitest reporter (#23457) (camc314) ### ⚡ Performance - cf24329 mangler: Compile slot sort once instead of per CAPACITY (#23577) (Boshen) - 4058a6a parser: Reduce code bloat from verify_modifiers monomorphization (#23576) (Boshen) - 053b0c1 estree: Remove pointless `mem::take` (#23572) (overlookmotel) - dfb52b6 transformer: Pre-size statement vecs in TS enum & namespace lowering (#23516) (Yunfei He) - 970e09a minifier: Compute template-literal inline checks in a single pass (#23467) (Yunfei He) - 3170c0e semantic,mangler,minifier: Fix `Semantic::stats` node count and reuse stats in mangler builds (#23352) (Boshen) - d1fa6e0 minifier: Evaluate ternary branches once in minimize_conditional_expression (#23479) (Yunfei He) - 3fa8051 transformer: Pre-size JSX props vec to attribute count (#23466) (Yunfei He) - 488b382 react_compiler: Borrow binding names in prefilter instead of allocating (#23471) (Yunfei He) - bcb3894 minifier: Incremental scoping refresh, delete LiveUsageCollector (#23197) (Dunqing) ### 📚 Documentation - f68641e data_structures: Improve docs on safety contract (#23575) (overlookmotel) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>

github-actions Bot added the A-minifier Area - Minifier label Jun 16, 2026

Dunqing marked this pull request as ready for review June 16, 2026 08:38

Dunqing force-pushed the fix/minifier-proxy-sensitive-object-methods branch from 83c8b80 to d30cfba Compare June 16, 2026 09:22

Dunqing added the run-monitor-oxc Add to a PR to dispatch oxc-project/monitor-oxc CI against it label Jun 16, 2026

oxc-guard Bot removed the run-monitor-oxc Add to a PR to dispatch oxc-project/monitor-oxc CI against it label Jun 16, 2026

gthb reviewed Jun 16, 2026

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Comment thread crates/oxc_ecmascript/src/side_effects/known_globals.rs Outdated

Comment thread crates/oxc_ecmascript/src/side_effects/expressions.rs Outdated

Dunqing requested a review from sapphi-red June 17, 2026 02:00

Dunqing added the 0-merge Merge with Graphite Merge Queue label Jun 17, 2026

graphite-app Bot force-pushed the fix/minifier-proxy-sensitive-object-methods branch from ccea0ac to 31bfd9b Compare June 17, 2026 08:08

graphite-app Bot merged commit 31bfd9b into main Jun 17, 2026
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graphite-app Bot removed the 0-merge Merge with Graphite Merge Queue label Jun 17, 2026

graphite-app Bot deleted the fix/minifier-proxy-sensitive-object-methods branch June 17, 2026 08:13

oxc-guard Bot mentioned this pull request Jun 18, 2026

release(crates): oxc v0.137.0 #23591

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sapphi-red reviewed Jun 18, 2026

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sapphi-red mentioned this pull request Jun 25, 2026

Object.isExtensible() should be treated as sideeffect free #23779

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fix(minifier): keep Object introspection calls on a possible Proxy#23483

fix(minifier): keep Object introspection calls on a possible Proxy#23483
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Monitor Oxc

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