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[v20.x] backport require(esm) and related patches #53500

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joyeecheung
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@joyeecheung joyeecheung commented Jun 18, 2024

This backports #51977 and related bug fixes. To reduce the amount of conflicts some other patches touching adjacent lines are also backported.

Note that src: backport FromV8Array is a special backport of #51758 which implements the internal API using the old array iteration approach, because the new V8 API is not available in v20.x - so it's still not going to get any benefit from the new API, but at least this helps reducing the source conflicts when backporting future commits that make use of the new faster callback-based array iteration API.

Module format detection is not backported because all the recent changes in format detection on the main branch are built on top of #50322. If #50322 is not backported first, rewriting the later changes to use the old internal API is going to make backporting it out-of-order even harder. But since that PR is pretty big and adds a new dependency it seems less risky to just backport that separately.

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Review requested:

  • @nodejs/loaders
  • @nodejs/vm

@nodejs-github-bot nodejs-github-bot added lib / src Issues and PRs related to general changes in the lib or src directory. needs-ci PRs that need a full CI run. v20.x v20.x Issues that can be reproduced on v20.x or PRs targeting the v20.x-staging branch. labels Jun 18, 2024
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cc @marco-ippolito

@joyeecheung joyeecheung added the request-ci Add this label to start a Jenkins CI on a PR. label Jun 18, 2024
@github-actions github-actions bot removed the request-ci Add this label to start a Jenkins CI on a PR. label Jun 18, 2024
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RSLGTM

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We have now the backport #53502 for #50322

joyeecheung and others added 6 commits July 30, 2024 15:53
This patch adds `require()` support for synchronous ESM graphs under
the flag `--experimental-require-module`

This is based on the the following design aspect of ESM:

- The resolution can be synchronous (up to the host)
- The evaluation of a synchronous graph (without top-level await) is
  also synchronous, and, by the time the module graph is instantiated
  (before evaluation starts), this is is already known.

If `--experimental-require-module` is enabled, and the ECMAScript
module being loaded by `require()` meets the following requirements:

- Explicitly marked as an ES module with a `"type": "module"` field in
  the closest package.json or a `.mjs` extension.
- Fully synchronous (contains no top-level `await`).

`require()` will load the requested module as an ES Module, and return
the module name space object. In this case it is similar to dynamic
`import()` but is run synchronously and returns the name space object
directly.

```mjs
// point.mjs
export function distance(a, b) {
  return (b.x - a.x) ** 2 + (b.y - a.y) ** 2;
}
class Point {
  constructor(x, y) { this.x = x; this.y = y; }
}
export default Point;
```

```cjs
const required = require('./point.mjs');
// [Module: null prototype] {
//   default: [class Point],
//   distance: [Function: distance]
// }
console.log(required);

(async () => {
  const imported = await import('./point.mjs');
  console.log(imported === required);  // true
})();
```

If the module being `require()`'d contains top-level `await`, or the
module graph it `import`s contains top-level `await`,
[`ERR_REQUIRE_ASYNC_MODULE`][] will be thrown. In this case, users
should load the asynchronous module using `import()`.

If `--experimental-print-required-tla` is enabled, instead of throwing
`ERR_REQUIRE_ASYNC_MODULE` before evaluation, Node.js will evaluate the
module, try to locate the top-level awaits, and print their location to
help users fix them.

PR-URL: nodejs#51977
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
This refactors the code that compiles SourceTextModule for the
built-in ESM loader to use a common routine so that it's easier
to customize cache handling for the ESM loader. In addition
this introduces a common symbol for import.meta and import()
so that we don't need to create additional closures as handlers,
since we can get all the information we need from the V8 callback
already. This should reduce the memory footprint of ESM as well.

PR-URL: nodejs#52291
Refs: nodejs#47472
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
This patch disallows CJS <-> ESM edges when they come from
require(esm) requested in ESM evalaution.

Drive-by: don't reuse the cache for imported CJS modules to stash
source code of required ESM because the former is also used for
cycle detection.

PR-URL: nodejs#52264
Fixes: nodejs#52145
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Symbol properties are typically more GC-efficient than using WeakMaps,
since WeakMap requires ephemeron GC. `module[kModuleExportNames]`
would be easier to read than `importedCJSCache.get(module).exportNames`
as well.

PR-URL: nodejs#52095
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
PR-URL: nodejs#52437
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Yagiz Nizipli <yagiz.nizipli@sentry.io>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Feng Yu <F3n67u@outlook.com>
Previously there is an edge case where submodules loaded by require()
may not be loaded by import() again from different intermediate
edges in the graph. This patch fixes that, added tests, and added
debug logs.

Drive-by: make loader a private field so it doesn't show up in logs.
PR-URL: nodejs#52487
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
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Rebased this branch. It looks like #53502 is getting stalled. This doesn't need to wait for that PR to get merged to v20.x though @marco-ippolito how should we proceed getting this into 20.x?

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Rebased this branch. It looks like #53502 is getting stalled. This doesn't need to wait for that PR to get merged to v20.x though @marco-ippolito how should we proceed getting this into 20.x?

If CI is green, Ill include it in the next 20 release

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lgtm

@joyeecheung joyeecheung added the request-ci Add this label to start a Jenkins CI on a PR. label Aug 4, 2024
@github-actions github-actions bot removed the request-ci Add this label to start a Jenkins CI on a PR. label Aug 4, 2024
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CI was green, should we merge this?

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I'll backport it today 💪🏻

marco-ippolito pushed a commit that referenced this pull request Aug 8, 2024
This patch adds `require()` support for synchronous ESM graphs under
the flag `--experimental-require-module`

This is based on the the following design aspect of ESM:

- The resolution can be synchronous (up to the host)
- The evaluation of a synchronous graph (without top-level await) is
  also synchronous, and, by the time the module graph is instantiated
  (before evaluation starts), this is is already known.

If `--experimental-require-module` is enabled, and the ECMAScript
module being loaded by `require()` meets the following requirements:

- Explicitly marked as an ES module with a `"type": "module"` field in
  the closest package.json or a `.mjs` extension.
- Fully synchronous (contains no top-level `await`).

`require()` will load the requested module as an ES Module, and return
the module name space object. In this case it is similar to dynamic
`import()` but is run synchronously and returns the name space object
directly.

```mjs
// point.mjs
export function distance(a, b) {
  return (b.x - a.x) ** 2 + (b.y - a.y) ** 2;
}
class Point {
  constructor(x, y) { this.x = x; this.y = y; }
}
export default Point;
```

```cjs
const required = require('./point.mjs');
// [Module: null prototype] {
//   default: [class Point],
//   distance: [Function: distance]
// }
console.log(required);

(async () => {
  const imported = await import('./point.mjs');
  console.log(imported === required);  // true
})();
```

If the module being `require()`'d contains top-level `await`, or the
module graph it `import`s contains top-level `await`,
[`ERR_REQUIRE_ASYNC_MODULE`][] will be thrown. In this case, users
should load the asynchronous module using `import()`.

If `--experimental-print-required-tla` is enabled, instead of throwing
`ERR_REQUIRE_ASYNC_MODULE` before evaluation, Node.js will evaluate the
module, try to locate the top-level awaits, and print their location to
help users fix them.

PR-URL: #51977
Backport-PR-URL: #53500
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
marco-ippolito pushed a commit that referenced this pull request Aug 8, 2024
This refactors the code that compiles SourceTextModule for the
built-in ESM loader to use a common routine so that it's easier
to customize cache handling for the ESM loader. In addition
this introduces a common symbol for import.meta and import()
so that we don't need to create additional closures as handlers,
since we can get all the information we need from the V8 callback
already. This should reduce the memory footprint of ESM as well.

PR-URL: #52291
Backport-PR-URL: #53500
Refs: #47472
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
marco-ippolito pushed a commit that referenced this pull request Aug 8, 2024
This patch disallows CJS <-> ESM edges when they come from
require(esm) requested in ESM evalaution.

Drive-by: don't reuse the cache for imported CJS modules to stash
source code of required ESM because the former is also used for
cycle detection.

PR-URL: #52264
Backport-PR-URL: #53500
Fixes: #52145
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
marco-ippolito pushed a commit that referenced this pull request Aug 8, 2024
Symbol properties are typically more GC-efficient than using WeakMaps,
since WeakMap requires ephemeron GC. `module[kModuleExportNames]`
would be easier to read than `importedCJSCache.get(module).exportNames`
as well.

PR-URL: #52095
Backport-PR-URL: #53500
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
marco-ippolito pushed a commit that referenced this pull request Aug 8, 2024
PR-URL: #52437
Backport-PR-URL: #53500
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Yagiz Nizipli <yagiz.nizipli@sentry.io>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Feng Yu <F3n67u@outlook.com>
@marco-ippolito
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Landed in 30b859f...7625dc4

marco-ippolito pushed a commit that referenced this pull request Aug 8, 2024
Previously there is an edge case where submodules loaded by require()
may not be loaded by import() again from different intermediate
edges in the graph. This patch fixes that, added tests, and added
debug logs.

Drive-by: make loader a private field so it doesn't show up in logs.
PR-URL: #52487
Backport-PR-URL: #53500
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
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