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Pass the exports object as this to exported functions that read sibling exports - #1610
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…ling exports
retry 0.13.1's `exports.timeouts` reads `this.createTimeout`, and
`exports.operation` calls it through the exports object; async-retry wraps
every request in an operation. A call through the exports object passes
that object as `this`, which compiles to a static table, so the call was
fenced ("calling 'exports.timeouts' through the module's exports object
when the function may read 'this'").
When every `this` in an exported function expression names another
export the module writes (`this.X` with `exports.X = …`), the exports
object is never replaced, and the module calls the function only through
`exports.f(…)`, a package-file stage now respells `this.X` as `exports.X`:
the member Node reads for those calls. Only a caller that detaches the
function or rebinds its `this` would observe a difference.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
…/npm-exports-this
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
# Conflicts: # tests/harness/npm-cases.ts # tests/harness/npm-static.test.ts
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…t shadow exports - A sibling read as a value through `this.f` inside the module (`var g = this.b; g()`) now counts as a detached use, as `exports.f` already did, so `b` keeps its `this`. - An exported function that declares its own `exports` binding (a parameter, a `var`, an arrow parameter or its own name) keeps its text, and so does a module that declares `exports` at module scope: the respelled reads would name that binding instead of the exports object.
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Pass the exports object as
thisto exported functions that read sibling exportsStacked on #1558.
Summary
Some CommonJS modules export plain functions that reach their sibling exports through
this:Node runs these with the exports object as
this, because callers writeretry.operation(...). scriptc compiled the function bodies without a receiver, so the firstthis.createTimeoutfailed. retry 0.13.1 is the most common example.A new package-file stage,
npm-static-exports-this.ts, runs before the interop-helper stage. Inside a top-levelexports.f = function () {…}, it respellsthis.Xasexports.X. It does so only when all of these hold:thisin the function, including inside arrows, is a read ofthis.<name>where<name>is one of the module's exports;exports =and nomodule.exports =);exports.fis only stored or called asexports.f(...), never passed around as a value.Under those rules,
thisandexportsare the same object for every call a consumer can make through the namespace, so the respelling preserves behavior. Any other shape keeps its text and its current diagnostics.Evidence
npm-static-exports-this.test.tsrun rewritten modules against their originals under Node. They also pin the shapes that must keep their text: athisvalue escaping, a non-export member, a replaced exports object, andexports.fused as a value.2597-exports-this: a generic package whose exported functions call each other throughthis, including from an arrow function. Its output is byte-identical to Node's.2598-retry-timeouts: the unmodified retry 0.13.1 package (MIT) as a fixture. It callsretry.timeouts(...)andretry.operation(...). Its output is byte-identical to Node's; before this change it failed at load.--corpus=all --timing-runs=3: 3433 of 3434 programs are identical. The one difference,fs-extra-package, is only the fs-extra shim's absolute checkout path.pnpm lint,pnpm format:checkandtest:ts7 --baselines-onlypass. The only baseline changes are new entries for the new cases.package-shimssuites, plus the frontend unit tests, pass 1153 of 1154. The one failure,node24-url-authority, is caused by the sandbox's Node 24.15 and also fails on the base.self-hosting-native-driver.test.tspasses (1092 s).🤖 Generated with Claude Code