refactor: pass arrays to AST builder methods by overlookmotel · Pull Request #10419 · rolldown/rolldown

overlookmotel · 2026-07-23T22:54:44Z

Follow-on after #10018.

The new AST builder methods allow passing arrays where a Vec is required. Use this facility to remove a lot of repetitious boilerplate.

Before:

FunctionBody::new(
  SPAN,
  oxc::allocator::Vec::new_in(&self.ast_builder),
  oxc::allocator::Vec::from_value_in(try_stmt, &self.ast_builder),
  &self.ast_builder,
)

After:

FunctionBody::new(SPAN, [], [try_stmt], &self.ast_builder)

Note: Like #10418, diff is quite large, but these changes were almost entirely produced using the same deterministic codemod we used to migrate Oxc repo to new AST builder, with only some final tweaks by an LLM. I've reviewed it all and, even though I'm unfamiliar with Rolldown's codebase, I'm pretty confident it looks correct.

overlookmotel · 2026-07-23T22:54:58Z

How to use the Graphite Merge Queue

Add the label graphite: merge-when-ready to this PR to add it to the merge queue.

You must have a Graphite account in order to use the merge queue. Sign up using this link.

_{An organization admin has enabled the Graphite Merge Queue in this repository.} _{Please do not merge from GitHub as this will restart CI on PRs being processed by the merge queue.}

This stack of pull requests is managed by Graphite. Learn more about stacking.

Copilot

Pull request overview

This PR continues the AST-construction refactor (follow-on after #10018) by leveraging oxc’s updated per-type AST constructors that accept array literals where an arena Vec was previously required, reducing boilerplate and improving readability at many call sites.

Changes:

Replaces oxc::allocator::Vec::{new_in, from_value_in, from_array_in} usages at constructor call sites with [] / [...] array literals where supported.
Simplifies construction of common AST nodes (calls, function bodies/params, object expressions, programs) across finalizers, HMR codegen, and plugins.
Keeps existing arena-allocated Vec usage where mutation/capacity management is still needed.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/rolldown/src/utils/tweak_ast_for_scanning.rs	Uses `[]` / `[...]` when constructing export decls and call arguments during preprocessing rewrites.
crates/rolldown/src/module_finalizers/mod.rs	Replaces many arena `Vec` constructions with array literals in scope-hoisting finalizer AST generation.
crates/rolldown/src/module_finalizers/impl_visit_mut.rs	Simplifies `ImportMeta` rewrite to an empty object literal via `new_object_expression(SPAN, [], ...)`.
crates/rolldown/src/hmr/utils.rs	Uses array literals for object properties and call arguments in HMR runtime registration AST.
crates/rolldown/src/hmr/impl_traverse_for_hmr_ast_finalizer.rs	Simplifies try/finally wrapper block/function construction using `[]` / `[...]`.
crates/rolldown/src/hmr/hmr_ast_finalizer.rs	Converts multiple call/sequence/function-body argument lists to array literals in HMR finalization logic.
crates/rolldown_plugin_vite_web_worker_post/src/ast_visitor.rs	Uses array literal for the single-property `importMeta` object expression.
crates/rolldown_plugin_vite_build_import_analysis/src/ast_utils.rs	Uses array literals for pattern properties and small single-item declaration lists.
crates/rolldown_plugin_lazy_compilation/src/runtime_injector.rs	Uses array literals for `.then(...)` args, formal params, and var decls in injected helper/function bodies.
crates/rolldown_ecmascript/src/ecma_compiler.rs	Builds a program from a parsed expression using `[]` / `[...]` for directives/comments/body.
crates/rolldown_ecmascript_utils/src/ast_factory.rs	Updates factory helpers to pass `[]` / `[...]` for params/bodies/args and keeps mutable arena `Vec` where needed.
crates/rolldown_common/src/ecmascript/json_to_program.rs	Builds a minimal program from JSON using array literals for directives/comments/body.

codspeed-hq · 2026-07-23T23:21:37Z

Merging this PR will not alter performance

✅ 7 untouched benchmarks
⏩ 10 skipped benchmarks¹

_{Comparing om/07-23-refactor_pass_arrays_to_ast_builder_methods (d5762eb) with om/07-23-refactor_shorten_ast_builder_code (4e5b677)²}

10 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. ↩
No successful run was found on om/07-23-refactor_shorten_ast_builder_code (8e20bae) during the generation of this report, so e803c3a was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

hyfdev

— Review by @hyfdev, assisted by GPT-5

graphite-app · 2026-07-24T03:38:45Z

Merge activity

Jul 24, 3:38 AM UTC: hyfdev added this pull request to the Graphite merge queue.
Jul 24, 3:54 AM UTC: Merged by the Graphite merge queue.

Follow-on after #10018. The new AST builder methods allow passing arrays where a `Vec` is required. Use this facility to remove a lot of repetitious boilerplate. Before: ```rust FunctionBody::new( SPAN, oxc::allocator::Vec::new_in(&self.ast_builder), oxc::allocator::Vec::from_value_in(try_stmt, &self.ast_builder), &self.ast_builder, ) ``` After: ```rust FunctionBody::new(SPAN, [], [try_stmt], &self.ast_builder) ``` Note: Like #10418, diff is quite large, but these changes were almost entirely produced using the same [deterministic codemod](https://github.com/oxc-project/oxc/tree/overlookmotel/ast-builder-codemod) we used to migrate Oxc repo to new AST builder, with only some final tweaks by an LLM. I've reviewed it all and, even though I'm unfamiliar with Rolldown's codebase, I'm pretty confident it looks correct.

overlookmotel marked this pull request as ready for review July 23, 2026 23:13

overlookmotel requested review from h-a-n-a, hyfdev and shulaoda as code owners July 23, 2026 23:13

Copilot AI review requested due to automatic review settings July 23, 2026 23:13

overlookmotel requested review from IWANABETHATGUY and sapphi-red as code owners July 23, 2026 23:13

Copilot started reviewing on behalf of overlookmotel July 23, 2026 23:14 View session

Copilot AI reviewed Jul 23, 2026

View reviewed changes

overlookmotel force-pushed the om/07-23-refactor_pass_arrays_to_ast_builder_methods branch from de7535b to d5762eb Compare July 24, 2026 00:02

overlookmotel force-pushed the om/07-23-refactor_shorten_ast_builder_code branch from 4e5b677 to 8e20bae Compare July 24, 2026 00:02

hyfdev approved these changes Jul 24, 2026

View reviewed changes

graphite-app Bot added the graphite: merge-when-ready label Jul 24, 2026

graphite-app Bot force-pushed the om/07-23-refactor_shorten_ast_builder_code branch from 8e20bae to 9886244 Compare July 24, 2026 03:43

graphite-app Bot force-pushed the om/07-23-refactor_pass_arrays_to_ast_builder_methods branch from d5762eb to 4240c14 Compare July 24, 2026 03:44

Base automatically changed from om/07-23-refactor_shorten_ast_builder_code to main July 24, 2026 03:50

graphite-app Bot removed the graphite: merge-when-ready label Jul 24, 2026

graphite-app Bot merged commit 4240c14 into main Jul 24, 2026
32 checks passed

graphite-app Bot deleted the om/07-23-refactor_pass_arrays_to_ast_builder_methods branch July 24, 2026 03:54

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

refactor: pass arrays to AST builder methods#10419

refactor: pass arrays to AST builder methods#10419
graphite-app[bot] merged 1 commit into
mainfrom
om/07-23-refactor_pass_arrays_to_ast_builder_methods

overlookmotel commented Jul 23, 2026 •

edited

Loading

Uh oh!

overlookmotel commented Jul 23, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

codspeed-hq Bot commented Jul 23, 2026 •

edited

Loading

Uh oh!

hyfdev left a comment

Uh oh!

graphite-app Bot commented Jul 24, 2026 •

edited

Loading

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Uh oh!

Conversation

overlookmotel commented Jul 23, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

overlookmotel commented Jul 23, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

How to use the Graphite Merge Queue

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

codspeed-hq Bot commented Jul 23, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Merging this PR will not alter performance

Footnotes

Uh oh!

hyfdev left a comment

Choose a reason for hiding this comment

Uh oh!

graphite-app Bot commented Jul 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Merge activity

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

overlookmotel commented Jul 23, 2026 •

edited

Loading

overlookmotel commented Jul 23, 2026 •

edited

Loading

codspeed-hq Bot commented Jul 23, 2026 •

edited

Loading

graphite-app Bot commented Jul 24, 2026 •

edited

Loading