Refactor to reduce Rollup 5 upgrade diff by lukastaegert · Pull Request #6246 · rollup/rollup

lukastaegert · 2026-01-24T09:22:55Z

This PR contains:

Are tests included?

yes (bugfixes and features will not be merged without tests)
no

Breaking Changes?

yes (breaking changes will not be merged unless absolutely necessary)
no

List any relevant issue numbers:

Description

In order to reduce the friction in the code base for the Rollup 5 update, this refactors to consistently use declare over "!".

vercel · 2026-01-24T09:23:00Z

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Project	Deployment	Review	Updated (UTC)
rollup	Ready	Preview, Comment	Jan 24, 2026 1:31pm

github-actions · 2026-01-24T09:27:46Z

Thank you for your contribution! ❤️

You can try out this pull request locally by installing Rollup via

npm install rollup/rollup#refactor-for-rollup-5

Notice: Ensure you have installed the latest nightly Rust toolchain. If you haven't installed it yet, please see https://www.rust-lang.org/tools/install to learn how to download Rustup and install Rust.

or load it into the REPL:
https://rollup-o0bgolabx-rollup-js.vercel.app/repl/?pr=6246

github-actions · 2026-01-24T09:28:23Z

Performance report

BUILD: 6882ms, 832 MB
- initialize: 0ms, 24.6 MB (+7%)
- generate module graph: 2621ms, 632 MB
  - generate ast: 1412ms, 626 MB
- sort and bind modules: 394ms (-11ms, -2.8%), 685 MB
- mark included statements: 3865ms, 832 MB
  - treeshaking pass 1: 2243ms, 835 MB (+2%)
  - treeshaking pass 2: 454ms, 843 MB
  - treeshaking pass 3: 393ms, 842 MB (+2%)
  - treeshaking pass 4: 381ms, 851 MB
  - treeshaking pass 5: 379ms, 832 MB
GENERATE: 685ms, 931 MB
- initialize render: 0ms, 832 MB
- generate chunks: 37ms, 842 MB
  - optimize chunks: 0ms, 834 MB
- render chunks: 630ms, 905 MB
- transform chunks: 17ms, 931 MB
- generate bundle: 0ms, 931 MB

Copilot

Pull request overview

Refactors TypeScript class property declarations to more closely match the Rollup 5 code style by replacing declare properties with definite assignment assertions (!:), aiming to reduce the eventual Rollup 5 upgrade diff.

Changes:

Replaced many declare class properties with definite assignment assertions (!:) across AST nodes, scopes, variables, and Module.
Minor import cleanup in UpdateExpression.
package-lock.json updated with substantial metadata/structure churn.

Reviewed changes

Copilot reviewed 83 out of 84 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
src/ast/variables/NamespaceVariable.ts	Converts `declare` properties to `!:` for Rollup 5 alignment.
src/ast/scopes/ModuleScope.ts	Converts `declare` property to `!:` for Rollup 5 alignment.
src/ast/nodes/shared/Node.ts	Converts core node `declare` properties to `!:`.
src/ast/nodes/shared/MethodBase.ts	Converts `declare` properties to `!:`.
src/ast/nodes/shared/JSXElementBase.ts	Converts `declare` property to `!:`.
src/ast/nodes/shared/FunctionNode.ts	Converts `declare` properties to `!:`.
src/ast/nodes/shared/FunctionBase.ts	Converts `declare` properties to `!:`.
src/ast/nodes/shared/ClassNode.ts	Converts `declare` properties to `!:`.
src/ast/nodes/shared/CallExpressionBase.ts	Converts `declare` property to `!:`.
src/ast/nodes/YieldExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/WhileStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/VariableDeclarator.ts	Converts `declare` properties to `!:`.
src/ast/nodes/VariableDeclaration.ts	Converts `declare` properties to `!:`.
src/ast/nodes/UpdateExpression.ts	Converts `declare` properties to `!:` and removes an unused type import.
src/ast/nodes/UnaryExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/TryStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ThrowStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ThisExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/TemplateLiteral.ts	Converts `declare` properties to `!:`.
src/ast/nodes/TemplateElement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/TaggedTemplateExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/SwitchStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/SwitchCase.ts	Converts `declare` properties to `!:`.
src/ast/nodes/Super.ts	Converts `declare` properties to `!:`.
src/ast/nodes/StaticBlock.ts	Converts `declare` properties to `!:`.
src/ast/nodes/SpreadElement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/SequenceExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ReturnStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/RestElement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/PropertyDefinition.ts	Converts `declare` properties to `!:`.
src/ast/nodes/Property.ts	Converts `declare` properties to `!:` and updates commented placeholders.
src/ast/nodes/Program.ts	Converts `declare` properties to `!:`.
src/ast/nodes/PrivateIdentifier.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ParseError.ts	Converts `declare` properties to `!:`.
src/ast/nodes/PanicError.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ObjectPattern.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ObjectExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/NewExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/MethodDefinition.ts	Converts `declare` properties to `!:`.
src/ast/nodes/MetaProperty.ts	Converts `declare` properties to `!:`.
src/ast/nodes/MemberExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/LogicalExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/Literal.ts	Converts `declare` properties to `!:`.
src/ast/nodes/LabeledStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ImportSpecifier.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ImportNamespaceSpecifier.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ImportExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ImportDefaultSpecifier.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ImportDeclaration.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ImportAttribute.ts	Converts `declare` properties to `!:`.
src/ast/nodes/IfStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/FunctionExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/FunctionDeclaration.ts	Converts `declare` property to `!:`.
src/ast/nodes/ForStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ForOfStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ForInStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ExpressionStatement.ts	Converts `declare` property to `!:`.
src/ast/nodes/ExportSpecifier.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ExportNamedDeclaration.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ExportDefaultDeclaration.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ExportAllDeclaration.ts	Converts `declare` properties to `!:`.
src/ast/nodes/EmptyStatement.ts	Converts `declare` property to `!:`.
src/ast/nodes/DoWhileStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/Decorator.ts	Converts `declare` properties to `!:`.
src/ast/nodes/DebuggerStatement.ts	Converts `declare` property to `!:`.
src/ast/nodes/ContinueStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ConditionalExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ClassExpression.ts	Converts `declare` property to `!:`.
src/ast/nodes/ClassDeclaration.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ClassBody.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ChainExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/CatchClause.ts	Converts `declare` properties to `!:`.
src/ast/nodes/CallExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/BreakStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/BlockStatement.ts	Converts `declare` properties to `!:`.
src/ast/nodes/BinaryExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/AwaitExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/AssignmentPattern.ts	Converts `declare` properties to `!:`.
src/ast/nodes/AssignmentExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ArrowFunctionExpression.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ArrayPattern.ts	Converts `declare` properties to `!:`.
src/ast/nodes/ArrayExpression.ts	Converts `declare` properties to `!:`.
src/Module.ts	Converts `declare` properties to `!:` on the `Module` class.
package-lock.json	Lockfile rewritten/normalized with many metadata/flag changes.

codecov · 2026-01-24T09:35:42Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.83%. Comparing base (7af842b) to head (9eec19b).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #6246   +/-   ##
=======================================
  Coverage   98.83%   98.83%           
=======================================
  Files         273      273           
  Lines       10692    10692           
  Branches     2849     2849           
=======================================
  Hits        10567    10567           
  Misses         82       82           
  Partials       43       43

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lukastaegert · 2026-01-24T13:20:25Z

The AI has some good points, I thought they would be mostly equivalent. I guess I will instead refactor in the Rollup-5 branch

Copilot

Pull request overview

Copilot reviewed 19 out of 20 changed files in this pull request and generated 1 comment.

github-actions · 2026-01-27T07:18:14Z

This PR has been released as part of [email protected]. You can test it via npm install rollup.

Copilot AI review requested due to automatic review settings January 24, 2026 09:22

vercel Bot deployed to Preview January 24, 2026 09:23 View deployment

Copilot started reviewing on behalf of lukastaegert January 24, 2026 09:24 View session

Copilot AI reviewed Jan 24, 2026

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lukastaegert closed this Jan 24, 2026

lukastaegert deleted the refactor-for-rollup-5 branch January 24, 2026 13:20

Refactor to reduce Rollup 5 upgrade diff

9eec19b

lukastaegert restored the refactor-for-rollup-5 branch January 24, 2026 13:29

lukastaegert reopened this Jan 24, 2026

lukastaegert force-pushed the refactor-for-rollup-5 branch from 64024fc to 9eec19b Compare January 24, 2026 13:29

lukastaegert requested a review from Copilot January 24, 2026 13:30

vercel Bot deployed to Preview January 24, 2026 13:31 View deployment

Copilot started reviewing on behalf of lukastaegert January 24, 2026 13:32 View session

Copilot AI reviewed Jan 24, 2026

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Comment thread src/ast/nodes/shared/JSXElementBase.ts

lukastaegert merged commit c519d82 into master Jan 24, 2026
54 checks passed

lukastaegert deleted the refactor-for-rollup-5 branch January 24, 2026 13:52

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Thank you for your contribution! ❤️

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