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Merged
marcins merged 3 commits into from
May 28, 2024
Merged

Ensure const modules in async bundles are wrapped #9740

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69c1c2c
Add failing integration test
marcins May 27, 2024
39a5e03
Wrap constant modules that might be imported async
marcins May 27, 2024
97abc6a
Ensure async value isn't inlined
marcins May 28, 2024
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42 changes: 42 additions & 0 deletions packages/core/integration-tests/test/bundler.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1214,6 +1214,48 @@ describe('bundler', function () {
]);
});

it('should support inline constants in async bundles', async () => {
await fsFixture(overlayFS, __dirname)`
inline-constants-async
index.js:
import('./async').then(m => console.log(m.value));

async.js:
export const value = 'async value';

package.json:
{
"@parcel/transformer-js": {
"unstable_inlineConstants": true
}
}

yarn.lock:`;

let b = await bundle(
path.join(__dirname, 'inline-constants-async/index.js'),
{
mode: 'production',
defaultTargetOptions: {
shouldScopeHoist: true,
sourceMaps: false,
shouldOptimize: false,
},
inputFS: overlayFS,
},
);

// This will fail when the async bundle does not export it's constant
await run(b);

@mattcompiles mattcompiles May 28, 2024

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Does the asset still get inlined in this case? It wouldn't be ideal if you ended up with something like:

import('./async').then(m => console.log('async value'));

@marcins marcins May 28, 2024

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Good question, it doesn't seem to - I assume the static analysis can't track the usage to that level anyway?

From the bundle in the integration test:

(parcelRequire("8Vicm")).then((m)=>console.log(m.value));

@marcins marcins May 28, 2024

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I've added additional verification in the integration test.


// Asset should not be inlined
const index = b.getBundles().find(b => b.name.startsWith('index'));
const contents = overlayFS.readFileSync(index.filePath, 'utf8');
assert(
!contents.includes('async value'),
'async value should not be inlined',
);
});
describe('manual shared bundles', () => {
const dir = path.join(__dirname, 'manual-bundle');

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8 changes: 7 additions & 1 deletion packages/packagers/js/src/ScopeHoistingPackager.js
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Original file line number Diff line number Diff line change
Expand Up @@ -317,7 +317,13 @@ export class ScopeHoistingPackager {
.getIncomingDependencies(asset)
.some(dep => dep.meta.shouldWrap && dep.specifierType !== 'url')
) {
if (!asset.meta.isConstantModule) {
// Don't wrap constant "entry" modules _except_ if they are referenced by any lazy dependency
if (
!asset.meta.isConstantModule ||
this.bundleGraph
.getIncomingDependencies(asset)
.some(dep => dep.priority === 'lazy')
) {
this.wrappedAssets.add(asset.id);
wrapped.push(asset);
}
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