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fix(minifier): keep new Map/WeakSet/WeakMap with a string argument#23470

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fix/minifier-keep-collection-string-throws
Jun 16, 2026
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fix(minifier): keep new Map/WeakSet/WeakMap with a string argument#23470
graphite-app[bot] merged 1 commit into
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fix/minifier-keep-collection-string-throws

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@Dunqing Dunqing commented Jun 16, 2026

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Summary

new Map("ab") / new WeakSet("ab") / new WeakMap("ab") throw at runtime ("a" is not a [k, v] entry, and is not an object), but the shared collection purity table treated Set, Map, WeakSet, and WeakMap identically and marked any string argument pure — so these throwing constructions were dropped when unused, silently removing an observable TypeError.

Split Set (which accepts any iterable of values, so a string argument is pure) from Map / WeakSet / WeakMap (which require [k, v] entries / object keys). A degenerate empty-string argument (new Map("") — pure, but never written in practice) is conservatively kept rather than special-cased.

This aligns with esbuild, which requires array-literal entries for these constructors. Pre-existing bug, surfaced while reviewing the parent PR (#23469).

Dunqing commented Jun 16, 2026

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@Dunqing Dunqing marked this pull request as ready for review June 16, 2026 04:12
@github-actions github-actions Bot added the A-minifier Area - Minifier label Jun 16, 2026
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codspeed-hq Bot commented Jun 16, 2026

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Merging this PR will not alter performance

✅ 52 untouched benchmarks
⏩ 19 skipped benchmarks1


Comparing fix/minifier-keep-collection-string-throws (e409fe0) with main (3fa8051)2

Open in CodSpeed

Footnotes

  1. 19 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.

  2. No successful run was found on main (b02444e) during the generation of this report, so 3fa8051 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report.

@Dunqing Dunqing force-pushed the fix/minifier-keep-collection-string-throws branch from 4e06c45 to 3f90446 Compare June 16, 2026 04:20
@Dunqing Dunqing force-pushed the feat/minifier-pure-typed-arrays-and-collections branch from 48bb82e to bee3c28 Compare June 16, 2026 04:29
@Dunqing Dunqing force-pushed the fix/minifier-keep-collection-string-throws branch from 3f90446 to 6e47b47 Compare June 16, 2026 04:29
@Dunqing Dunqing requested a review from sapphi-red June 16, 2026 07:30
@Dunqing Dunqing added the 0-merge Merge with Graphite Merge Queue label Jun 16, 2026

Dunqing commented Jun 16, 2026

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@graphite-app graphite-app Bot force-pushed the feat/minifier-pure-typed-arrays-and-collections branch from bee3c28 to 53509a8 Compare June 16, 2026 07:46
graphite-app Bot pushed a commit that referenced this pull request Jun 16, 2026
…ent (#23470)

## Summary

`new Map("ab")` / `new WeakSet("ab")` / `new WeakMap("ab")` throw at runtime (`"a"` is not a `[k, v]` entry, and is not an object), but the shared collection purity table treated `Set`, `Map`, `WeakSet`, and `WeakMap` identically and marked any string argument pure — so these throwing constructions were dropped when unused, silently removing an observable `TypeError`.

Split `Set` (which accepts any iterable of values, so a string argument is pure) from `Map` / `WeakSet` / `WeakMap` (which require `[k, v]` entries / object keys). A degenerate empty-string argument (`new Map("")` — pure, but never written in practice) is conservatively kept rather than special-cased.

This aligns with esbuild, which requires array-literal entries for these constructors. Pre-existing bug, surfaced while reviewing the parent PR (#23469).
@graphite-app graphite-app Bot force-pushed the fix/minifier-keep-collection-string-throws branch from 6e47b47 to d63771e Compare June 16, 2026 07:47
Base automatically changed from feat/minifier-pure-typed-arrays-and-collections to main June 16, 2026 07:51
@graphite-app graphite-app Bot removed the 0-merge Merge with Graphite Merge Queue label Jun 16, 2026
…ent (#23470)

## Summary

`new Map("ab")` / `new WeakSet("ab")` / `new WeakMap("ab")` throw at runtime (`"a"` is not a `[k, v]` entry, and is not an object), but the shared collection purity table treated `Set`, `Map`, `WeakSet`, and `WeakMap` identically and marked any string argument pure — so these throwing constructions were dropped when unused, silently removing an observable `TypeError`.

Split `Set` (which accepts any iterable of values, so a string argument is pure) from `Map` / `WeakSet` / `WeakMap` (which require `[k, v]` entries / object keys). A degenerate empty-string argument (`new Map("")` — pure, but never written in practice) is conservatively kept rather than special-cased.

This aligns with esbuild, which requires array-literal entries for these constructors. Pre-existing bug, surfaced while reviewing the parent PR (#23469).
@graphite-app graphite-app Bot force-pushed the fix/minifier-keep-collection-string-throws branch from d63771e to e409fe0 Compare June 16, 2026 07:52
@graphite-app graphite-app Bot merged commit e409fe0 into main Jun 16, 2026
36 checks passed
@graphite-app graphite-app Bot deleted the fix/minifier-keep-collection-string-throws branch June 16, 2026 07:56
Boshen added a commit that referenced this pull request Jun 18, 2026
### 💥 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>
camc314 pushed a commit that referenced this pull request Jul 3, 2026
…ent (#23470)

## Summary

`new Map("ab")` / `new WeakSet("ab")` / `new WeakMap("ab")` throw at runtime (`"a"` is not a `[k, v]` entry, and is not an object), but the shared collection purity table treated `Set`, `Map`, `WeakSet`, and `WeakMap` identically and marked any string argument pure — so these throwing constructions were dropped when unused, silently removing an observable `TypeError`.

Split `Set` (which accepts any iterable of values, so a string argument is pure) from `Map` / `WeakSet` / `WeakMap` (which require `[k, v]` entries / object keys). A degenerate empty-string argument (`new Map("")` — pure, but never written in practice) is conservatively kept rather than special-cased.

This aligns with esbuild, which requires array-literal entries for these constructors. Pre-existing bug, surfaced while reviewing the parent PR (#23469).
camc314 pushed a commit that referenced this pull request Jul 3, 2026
### 💥 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>
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