PIFE is the abbreviation of "Possibly-Invoked Function Expressions". It is a function expression wrapped with a parenthesized expression.
PIFEs annotate functions that are likely to be invoked eagerly. When v8 encounters such expressions, it compiles them eagerly (rather than compiling it later). See [v8's blog post](https://v8.dev/blog/preparser#pife) for more details.

The blog post only mentions regular FunctionExpressions, but ArrowFunctions are also supported. The cases that will be eagerly compiled are:

- when `!` comes before function literals ([code](https://github.com/v8/v8/blob/328f6c467b940f322544567740c9c871064d045c/src/parsing/parser-base.h#L3730-L3733)) (e.g. `!function(){}`)
- when a function expression is wrapped with parenthesis ([code](https://github.com/v8/v8/blob/328f6c467b940f322544567740c9c871064d045c/src/parsing/parser-base.h#L2243-L2248)) (e.g. `(function () {})`, `(async function () {})`)
- when an arrow function is wrapped with parenthesis ([code1](https://github.com/v8/v8/blob/328f6c467b940f322544567740c9c871064d045c/src/parsing/parser-base.h#L2173-L2174), [code2](https://github.com/v8/v8/blob/328f6c467b940f322544567740c9c871064d045c/src/parsing/parser-base.h#L2232-L2259), [code3](https://github.com/v8/v8/blob/328f6c467b940f322544567740c9c871064d045c/src/parsing/parser-base.h#L3297-L3298)) (e.g. `console.log((() => {}))`)
- when `()` or ``` `` ``` (tagged templates) comes after function literals (only in some cases) ([code1](https://github.com/v8/v8/blob/328f6c467b940f322544567740c9c871064d045c/src/parsing/parser-base.h#L3987-L3992), [code2](https://github.com/v8/v8/blob/328f6c467b940f322544567740c9c871064d045c/src/parsing/parser-base.h#L4344-L4348)) (e.g. `~function(){}()`, ```~function(){}`` ```)
- when [explicit compile hints](https://v8.dev/blog/explicit-compile-hints) are used ([code1](https://github.com/v8/v8/blob/328f6c467b940f322544567740c9c871064d045c/src/parsing/parser.cc#L2717-L2720), [code2](https://github.com/v8/v8/blob/328f6c467b940f322544567740c9c871064d045c/src/parsing/parser-base.h#L5070-L5073)) (e.g. `//# allFunctionsCalledOnLoad`)

Keeping PIFEs as-is in the code generation will unlock optimizations like rolldown/rolldown#5319.

_Note: this PR only implements arrow function PIFEs for now._

Same with #5319 but for `__esm`.

This change causes many diffs against esbuild. Should I add something to
reduce the diff?

Same with #5319 but for `createEsmInitializer`.

…wrapper (#5426)

Same with #5319 but for `__commonJSMin` / `_commonJS`.

Same with #5319 but for `createCjsInitializer`.

## [1.0.0-beta.30] - 2025-07-30

### 💥 BREAKING CHANGES

- rolldown: remove unfinished module federation support (#5471) by @Boshen
- disable `strictExecutionOrder` by default (#5436) by @hyf0

### 🚀 Features

- hmr: multiple changes should result to multiple updates (#5500) by @hyf0
- binding: add memory adjustment hint in fn write (#5375) by @Brooooooklyn
- store sideEffects information about global var access (#5495) by @IWANABETHATGUY
- merge side effects detail (#5486) by @IWANABETHATGUY
- plugin/vite-resolve: add warn / debug logs (#5476) by @sapphi-red
- plugin/vite-resolve: avoid wrapping errors with napi errors (#5483) by @sapphi-red
- add `this.fs` support (#5475) by @sapphi-red
- rolldown_plugin_asset: align `generate_bundle` logic (#5480) by @shulaoda
- hmr: prepare to launch that batched edits should result to multiple hmr output (#5458) by @hyf0
- hmr: support `import.meta.hot.invalidate` (#5457) by @hyf0
- mark all `toESM` as pure (#5461) by @IWANABETHATGUY
- rolldown_plugin_asset: align load hook logic (#5452) by @shulaoda
- rolldown_plugin_utils: align `file_to_built_url` (#5450) by @shulaoda
- rolldown_plugin_utils: align `should_inline` logic (#5308) by @AliceLanniste
- rolldown_plugin_asset: add partial `file_to_built_url` support (#5445) by @shulaoda
- expose `optimization.pifeForModuleWrappers` option (#5433) by @sapphi-red
- add `optimization.pifeForModuleWrappers` option (#5432) by @sapphi-red
- use PIFE for callback passed to `createCjsInitializer` (#5427) by @sapphi-red
- use PIFE for callbacks passed to `__commonJSMin` / `_commonJS` wrapper (#5426) by @sapphi-red
- use PIFE for callback passed to `createEsmInitializer` (#5425) by @sapphi-red
- use PIFE for callbacks passed to `__esm` wrapper (#5424) by @sapphi-red
- use PIFE for callbacks passed to `__esmMin` wrapper (#5319) by @sapphi-red
- rolldown: oxc v0.78.0 (#5421) by @Boshen
- rolldown: support `output.sourcemapBaseUrl` (#5413) by @situ2001
- mark all `__commonJS` CallExpression as **Pure** (#5419) by @IWANABETHATGUY
- rolldown_plugin_alias: warn if alias resolves to non-absolute path (#5417) by @shulaoda
- rolldown_plugin_asset: align `encode_uri_path` logic (#5410) by @shulaoda
- add warning and conversion for `import.meta` for non-`esm` output format (#5378) by @7086cmd

### 🐛 Bug Fixes

- use uuid_v4 to generate unique id for hook calls (#5501) by @hyf0
- modules that are sideeffect free but relies on the execution order is not wrapped (#5498) by @IWANABETHATGUY
- missing_export warning should not be an hard error (#5493) by @sapphi-red
- cli: remove unnecessary `await` (#5487) by @situ2001
- browser: stub fs/promises for browser build (#5484) by @sapphi-red
- indirect requiring external module  is not wrapped by `__toESM` in cjs format (#5454) by @IWANABETHATGUY
- Panic on reexport external module in  CJS format (#5430) by @IWANABETHATGUY
- handle top-level return statements in CommonJS modules (#5437) by @hyf0
- panic when using preserveModules: true and certain dependencies (#5415) by @IWANABETHATGUY
- rolldown_plugin_alias: only replace the first matched alias (#5412) by @shulaoda
- canonical name not found panic happens with treeshake.commonjs=true (#5409) by @IWANABETHATGUY
- hmr: shouldn't consider self-accepting module as hmr boundary for its importee (#5405) by @hyf0
- hmr: should detect hmr boundary correctly (#5400) by @hyf0
- optimization.inlineConst: true generates invalid code when importing a module statically and dynamically (#5398) by @IWANABETHATGUY
- top level VarDeclaration is not hoisted when wrapped in `__esm` (#5396) by @IWANABETHATGUY

### 🚜 Refactor

- use pascal case when naming bitflags field (#5497) by @IWANABETHATGUY
- test/hmr: use sensible time to wait (#5490) by @hyf0
- hmr: update message types to use 'hmr:update' (#5489) by @hyf0
- hmr: replace `HmrOutput` with `HmrUpdate` (#5488) by @hyf0
- node/hmr: re-organize file structures (#5485) by @hyf0
- rolldown_plugin_utils: improve `asset_to_data_url` (#5481) by @shulaoda
- replace pattern match for SideEffectsDetail with bitflags api (#5479) by @IWANABETHATGUY
- rename stmtSideEffect to SideEffectDetail (#5478) by @IWANABETHATGUY
- use bitflags store more details about side effects (#5477) by @IWANABETHATGUY
- node/hmr: tweak package `test-dev-server` (#5462) by @hyf0
- hmr: tweak naming and add comments (#5459) by @hyf0
- test/hmr: remove hard-code edited content (#5189) by @hyf0
- rust: make `Log#code` an `Option` (#5416) by @shulaoda
- hmr: should mark self-accept module correctly (#5406) by @hyf0
- hmr: remove unnecessary data during `propagate_update` (#5402) by @hyf0
- hmr: make hmr patch output less changeable (#5401) by @hyf0
- `__esm` top level bindings hoisted (#5397) by @IWANABETHATGUY
- skip fast in  esm format when transform import.meta (#5395) by @IWANABETHATGUY

### 📚 Documentation

- clarify rolldown-rollup behavior difference around output generation (#5439) by @sapphi-red

### ⚡ Performance

- reduce runtime symbol memory usage and hashtable lookup (#5460) by @IWANABETHATGUY

### 🧪 Testing

- hmr: support to run mutiple test fixtures (#5456) by @hyf0
- basic tests for `optimization.pifeForModuleWrappers` (#5435) by @sapphi-red

### ⚙️ Miscellaneous Tasks

- deps: update github-actions (#5509) by @renovate[bot]
- debug: update default session ID to meaningful `unknown-session` (#5502) by @hyf0
- deps: update dependency rolldown-plugin-dts to v0.14.2 (#5492) by @renovate[bot]
- auto generated runtime_helper bitflags (#5474) by @IWANABETHATGUY
- fix wasi build failed (#5470) by @IWANABETHATGUY
- deps: lock file maintenance (#5467) by @renovate[bot]
- deps: lock file maintenance (#5466) by @renovate[bot]
- deps: lock file maintenance rust crates (#5465) by @renovate[bot]
- deps: lock file maintenance npm packages (#5464) by @renovate[bot]
- deps: update github-actions (#5463) by @renovate[bot]
- export `__commonJSMin` in runtime-base.js (#5455) by @IWANABETHATGUY
- rolldown_plugin_utils: remove `file_to_dev_url` temporarily (#5446) by @shulaoda
- rolldown_plugin_asset: move `remove_url_query` into `rolldown_plugin_utils` (#5444) by @shulaoda
- rolldown: disable aarch64 atomics (#5447) by @Brooooooklyn
- remove diff with esbuild (#5428) by @IWANABETHATGUY
- dx/ai: add deepwiki badge to enable automatic refresh (#5423) by @hyf0
- dx/ai: Use `.cursorignore` to ignore meaningless files for AI (#5422) by @hyf0
- rolldown_plugin_alias: inline matches and remove redundant comment (#5418) by @shulaoda
- rolldown_plugin_asset: remove unnecessary comments (#5411) by @shulaoda
- rolldown_plugin_manifest: remove unnecessary code (#5408) by @shulaoda
- deps: update dependency tsdown to v0.13.0 (#5392) by @renovate[bot]