Skip to content

feat(minfier): drop last break from last switch case#24673

Merged
Dunqing merged 1 commit into
oxc-project:mainfrom
armano2:fix/drop-last-break-from-switch-case
Jul 20, 2026
Merged

feat(minfier): drop last break from last switch case#24673
Dunqing merged 1 commit into
oxc-project:mainfrom
armano2:fix/drop-last-break-from-switch-case

Conversation

@armano2

@armano2 armano2 commented Jul 19, 2026

Copy link
Copy Markdown
Contributor

After many trial and errors, this seem to be the best way to remove break stmts in switch cases,

This change targets only last break in last case of switch smts if its unlabelled

this change differs from #23914 as its no longer targets all branches as that should not be no longer necessary if all cases are correctly rewritten

#24672


cases like switch (a) { case 3: if (b) break; } are not changed


ref: #17544

@codspeed-hq

codspeed-hq Bot commented Jul 19, 2026

Copy link
Copy Markdown

Merging this PR will not alter performance

✅ 57 untouched benchmarks
⏩ 19 skipped benchmarks1


Comparing armano2:fix/drop-last-break-from-switch-case (6360f93) with main (dd18383)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 (0ed53f1) during the generation of this report, so dd18383 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report.

@armano2
armano2 marked this pull request as ready for review July 19, 2026 15:03
@Dunqing

Dunqing commented Jul 20, 2026

Copy link
Copy Markdown
Member

@codex review

@chatgpt-codex-connector

Copy link
Copy Markdown

Codex Review: Didn't find any major issues. Hooray!

Reviewed commit: 6360f9359b

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

  • Open a pull request for review
  • Mark a draft as ready
  • Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

@Dunqing Dunqing changed the title feat(minifer): drop last break from last switch case feat(minfier): drop last break from last switch case Jul 20, 2026

@Dunqing Dunqing left a comment

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Nice!

@Dunqing
Dunqing merged commit 7b045cd into oxc-project:main Jul 20, 2026
42 checks passed
@armano2
armano2 deleted the fix/drop-last-break-from-switch-case branch July 20, 2026 12:47
camc314 added a commit that referenced this pull request Jul 21, 2026
### 💥 BREAKING CHANGES

- 54cc121 ast: [**BREAKING**] Split `MetaProperty` into `ImportMeta` and
`NewTarget` (#24557) (camc314)

### 🚀 Features

- 4c71560 parser: More friendly error for spread element in dynamic
imports (#24705) (sapphi-red)
- 7b045cd minfier: Drop last break from last switch case (#24673)
(Armano)
- 7d3c178 minifier: Remove unreachable recursive functions (#24125)
(Dunqing)
- 94f99b3 ast: Allow `NONE` to be passed to AST builder methods where
`Option<ArenaVec>` is expected (#24629) (overlookmotel)
- 77230c5 ast: Accept arrays for `ArenaVec` params of AST builder
methods (#24621) (overlookmotel)
- f08b152 allocator: Implement `FromIn` for array to `Vec` conversion
(#24620) (overlookmotel)
- 2338c13 track-memory-allocations: Track heap deallocs, alloc bytes,
and peak growth (#24619) (Boshen)
- 7aa4739 syntax,transformer: Move JSX entity decoder to `oxc_syntax`
(#24617) (camc314)
- 2b097c4 str: Export `Str` as `ArenaStr` (#24604) (overlookmotel)
- 3acf4c1 minifier: Expand switch optimiation to remove empty cases
(#24520) (Armano)
- 129b759 parser: Improve diagnostics for unparenthesized LHS on
exponential expr (#24569) (camc314)
- 4d0c601 minifier: Fold arithmetic over undefined and null operands
(#24485) (Dunqing)
- 91541dd minifier: Drop empty switch statements  (#24527) (Armano)
- d05224d ast_visit: Generate VisitJs visitor that skips TypeScript
type-space (#24499) (Boshen)
- 3d22307 parser: Add `ParseOptions::enable_ident_hashes` (#24491)
(Boshen)

### 🐛 Bug Fixes

- 64c2241 minifier: Align class heritage removal with assumptions
(#24533) (Dunqing)
- 48b59f4 parser: Span ambient generator diagnostics (#24711) (camc314)
- e750a82 ecmascript: Fix false negative for may_have_side_effects on
dynamic property access (#24709) (sapphi-red)
- f145d73 minifier: Guard reordered identifier reads (#24698) (Dunqing)
- a2ef382 isolated-declarations: Reject `window.Symbol` as global symbol
reference (#24689) (camc314)
- b1bcf72 minifier: Invalidate facts for redeclared bindings (#24658)
(Dunqing)
- 921b834 minifier: Don't treat a conditionally-assigned var as
write-once (#24650) (Dunqing)
- 061af1f minifier: Avoid stale pure function summaries (#24636)
(Dunqing)
- 40c2f43 allocator: `Vec::from_array_in` do not allocate zero-length
array (#24628) (overlookmotel)
- 70994ae codegen: Preserve comments before expression operands (#24510)
(Dunqing)
- 7b4baff parser: Reject new import member access (#23459) (camc314)
- 128b385 minifier: Clippy warning with no-debug-assertions (#24547)
(camc314)
- 8421feb parser: Use first `as` span for imported name (#24537)
(leaysgur)
- c517aa0 parser: Reject invalid accessor assertions (#24504) (camc314)

### ⚡ Performance

- 884d9eb parser: Pre-size cover-grammar assignment target buffers
(#24683) (Boshen)
- d3f07a0 diagnostics: Box OxcDiagnosticInner to reduce binary size
(#24665) (Boshen)
- bcc9de0 parser: Defer diagnostic creation until parse exit (#24663)
(Boshen)
- c35d8ab allocator: Mark `ReplaceWith` panic path cold (#24515)
(camc314)
- ba65790 semantic, allocator: Branchless `clone_in` for semantic IDs
(#24564) (overlookmotel)
- 747feec parser: Build AST nodes with the AST builder instead of
cloning (#24540) (Boshen)
- ba35a0d react_compiler: Use IndexVec for dense id-keyed maps (#24549)
(Boshen)
- b685062 react_compiler: Keep small hot-path collections inline
(#24514) (Marius Schulz)
- a149e95 transformer: Outline rare expression exits (#24512) (camc314)
- 7808a6e react_compiler: Make aliasing effects cheap to intern and
clone (#24506) (Marius Schulz)
- 3a36f2a react_compiler: Store AbstractValue reasons as a u16 bitmask
(#24480) (Boshen)
- 1c96753 react_compiler: Use FxHashMap for the lookup-only aliasing
node map (#24490) (Boshen)

Co-authored-by: Cameron <[email protected]>
camc314 added a commit that referenced this pull request Jul 21, 2026
# Oxlint
### 💥 BREAKING CHANGES

- 54cc121 ast: [**BREAKING**] Split `MetaProperty` into `ImportMeta` and
`NewTarget` (#24557) (camc314)

### 🚀 Features

- 7b045cd minfier: Drop last break from last switch case (#24673)
(Armano)
- dd18383 linter/node: Implement no-top-level-await rule (#24634)
(Connor Shea)
- 16a65f2 linter/react: Implement function-component-definition rule
(#24471) (Cole Ellison)
- 7f1f585 linter: Reuse `jest/padding-around-test-blocks` for
`vitest/padding-around-test-blocks` (#24519) (Mikhail Baev)
- 99978a8 linter/import/consistent-type-specifier-style: Support
`prefer-top-level-if-only-type-imports` option (#24502) (camc314)

### 🐛 Bug Fixes

- 0184ad6 linter/unicorn/no-useless-undefined: Preserve valid parameter
defaults (#24686) (camc314)
- 8694167 linter/eslint/prefer-destructuring: Handle typed declarations
(#24616) (camc314)
- 477cf0f linter/eslint/no-throw-literal: Handle assigned errors
(#24561) (Cole Ellison)
- ac9200a linter: Detect React components from returned JSX (#24521)
(camc314)
- c0a6522 linter/eslint/no-useless-computed-key: Allow TS syntax in
computed keys (#24524) (Cole Ellison)

### ⚡ Performance

- 346eed1 linter/unicorn/prefer-event-target: Only run on `Class` and
`NewExpression` nodes (#24685) (Mikhail Baev)
- 7be5cf0 oxlint/lsp: Only invoke lint on code actions when document is
not opened (#24676) (Sysix)
- d3f07a0 diagnostics: Box OxcDiagnosticInner to reduce binary size
(#24665) (Boshen)
- 90ae040 linter/reporter/stylish: Compute diagnostic Info once per
diagnostic (#24525) (connorshea)

### 📚 Documentation

- e6f7174 linter/valid-expect: Fix correct example being identical to
incorrect one (#24468) (mkan0141)
# Oxfmt
### 💥 BREAKING CHANGES

- 54cc121 ast: [**BREAKING**] Split `MetaProperty` into `ImportMeta` and
`NewTarget` (#24557) (camc314)

### 🚀 Features

- 3d22307 parser: Add `ParseOptions::enable_ident_hashes` (#24491)
(Boshen)

### 🐛 Bug Fixes

- 6fe866a oxfmt: Keep tailwind classes glued to template expr with
`preserveWhitespace` (#24609) (leaysgur)
- 33e32d8 formatter_css: Use `line_suffix` for EOL line comment (#24580)
(leaysgur)
- 5f76998 formatter_graphql: Keep same line comments pending across
intervening tokens (#24579) (leaysgur)

Co-authored-by: Boshen <[email protected]>
Co-authored-by: Cameron <[email protected]>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

2 participants