Preserve correct `this` for named/default imports #7956

mischnic · 2022-04-14T16:08:32Z

Wraps references to named/default imports with (0, id) like swc/Babel does, so the output is:

    unwrappedNamed: (0, $54cf8bc5675f73b7$export$f7e507eb2d15e768)(),
    unwrappedDefault: (0, $54cf8bc5675f73b7$export$2e2bcd8739ae039)(),
    unwrappedNamespace: $54cf8bc5675f73b7$export$f7e507eb2d15e768(),
    wrappedNamed: (0, $gL1rG.returnThis)(),
    wrappedDefault: (0, $gL1rG.default)(),
    wrappedNamespace: $gL1rG.returnThis()

Problems

I've had to make the packager insert "use strict" to make the test pass. (For the this === ns check).
The added scope hoisting test is failing because for wrapped assets, self-imports of the namespace aren't left alone (should just be module.exports): Fix wrapped assets importing their own namespace #7978

dist/index.js:58
        this === $c332282c8a373e77$exports
                 ^

ReferenceError: $c332282c8a373e77$exports is not defined

mischnic · 2022-04-14T16:28:22Z

packages/transformers/js/core/src/hoist.rs

+      Expr::Ident(ident) => {
+        if let Some(Import { specifier, .. }) = self.collect.imports.get(&id!(ident)) {
+          if specifier != "*" {
+            return Expr::Seq(SeqExpr {
+              span: ident.span,
+              exprs: vec![0.into(), Box::new(Expr::Ident(ident.fold_with(self)))],
+            });
+          }
+        }
+        return Expr::Ident(ident.fold_with(self));
+      }


A cleaner fix (and what I tried to do first) was to move the fold_ident function into this match. But fold_ident runs not only referenced identifiers (=Expr::Ident) but also the names of function/variable declarations.
I'm not sure if it would make sense to split up fold_ident/extract the parts we need and use them here directly instead.

parcel-benchmark · 2022-04-14T16:49:10Z

Benchmark Results

Kitchen Sink 🚨

Timings

Description	Time	Difference
Cold	FAILED	-0.00ms
Cached	FAILED	-0.00ms

Cold Bundles

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Cached Bundles

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Timings

Description	Time	Difference
Cold	10.85s	-202.00ms
Cached	506.00ms	+33.00ms ⚠️

Cold Bundles

Bundle	Size	Difference	Time	Difference
dist/index.js	486.35kb	-2.46kb 🚀	5.69s	-213.00ms
dist/PermalinkedComment.46b19af5.js	4.21kb	-26.00b 🚀	5.69s	-213.00ms
dist/logo.c5bb83f1.png	246.00b	+0.00b	4.78s	-1.08s 🚀

Cached Bundles

Bundle	Size	Difference	Time	Difference
dist/index.js	486.35kb	-2.46kb 🚀	5.69s	-75.00ms
dist/PermalinkedComment.46b19af5.js	4.21kb	-26.00b 🚀	5.69s	-76.00ms

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Timings

Description	Time	Difference
Cold	FAILED	-0.00ms
Cached	FAILED	-0.00ms

Cold Bundles

No bundles found, this is probably a failed build...

Cached Bundles

No bundles found, this is probably a failed build...

Three.js ✅

Timings

Description	Time	Difference
Cold	7.71s	+55.00ms
Cached	307.00ms	+11.00ms

Cold Bundles

Bundle	Size	Difference	Time	Difference
dist/Three.js	579.69kb	+368.00b ⚠️	5.55s	+82.00ms

Cached Bundles

Bundle	Size	Difference	Time	Difference
dist/Three.js	579.69kb	+368.00b ⚠️	5.61s	+171.00ms

Click here to view a detailed benchmark overview.

devongovett · 2022-04-20T13:23:53Z

Looks like a bunch of tests are failing

parcel-benchmark · 2022-04-20T19:48:33Z

Benchmark Results

Kitchen Sink 🚨

Timings

Description	Time	Difference
Cold	FAILED	-0.00ms
Cached	FAILED	-0.00ms

Cold Bundles

No bundles found, this is probably a failed build...

Cached Bundles

No bundles found, this is probably a failed build...

React HackerNews ✅

Timings

Description	Time	Difference
Cold	10.93s	-50.00ms
Cached	563.00ms	+47.00ms ⚠️

Cold Bundles

Bundle	Size	Difference	Time	Difference
dist/index.js	486.35kb	-2.46kb 🚀	5.75s	-11.00ms
dist/PermalinkedComment.46b19af5.js	4.21kb	-26.00b 🚀	5.75s	-11.00ms

Cached Bundles

Bundle	Size	Difference	Time	Difference
dist/index.js	486.35kb	-2.46kb 🚀	5.63s	-189.00ms
dist/PermalinkedComment.46b19af5.js	4.21kb	-26.00b 🚀	5.63s	-188.00ms

AtlasKit Editor 🚨

Timings

Description	Time	Difference
Cold	FAILED	-0.00ms
Cached	FAILED	-0.00ms

Cold Bundles

No bundles found, this is probably a failed build...

Cached Bundles

No bundles found, this is probably a failed build...

Three.js ✅

Timings

Description	Time	Difference
Cold	7.99s	+157.00ms
Cached	311.00ms	-17.00ms 🚀

Cold Bundles

Bundle	Size	Difference	Time	Difference
dist/Three.js	579.69kb	+368.00b ⚠️	5.73s	+126.00ms

Cached Bundles

Bundle	Size	Difference	Time	Difference
dist/Three.js	579.69kb	+368.00b ⚠️	5.78s	+147.00ms

Click here to view a detailed benchmark overview.

mischnic · 2022-04-21T22:04:31Z

Looks like a bunch of tests are failing

Because of nodejs/node#38918... I'll probably have to change the fixtures to do global.output = ... instead.

mischnic · 2022-05-13T16:57:37Z

I've removed the change to insert use strict in the packager and instead simply tell run to use strict mode.

mischnic force-pushed the named-import-this branch from b18670d to 67bfa06 Compare April 14, 2022 16:09

mischnic commented Apr 14, 2022

View reviewed changes

devongovett approved these changes Apr 15, 2022

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mischnic mentioned this pull request Apr 19, 2022

Fix wrapped assets importing their own namespace #7978

Merged

mischnic force-pushed the named-import-this branch from d5224fd to 7b1b9c2 Compare April 20, 2022 19:14

wbinnssmith approved these changes Apr 22, 2022

View reviewed changes

mischnic added 3 commits May 13, 2022 18:56

Add test

0e0fbc9

Adjust this for non-scope-hoisting

78d4702

Adjust this for scope-hoisting

60cc6ec

mischnic force-pushed the named-import-this branch from ba379a6 to 60cc6ec Compare May 13, 2022 16:56

Update existing assertions

c331dc2

devongovett approved these changes May 17, 2022

View reviewed changes

mischnic merged commit a1e9ce5 into v2 May 17, 2022

mischnic deleted the named-import-this branch May 17, 2022 13:06

mischnic added a commit that referenced this pull request May 22, 2022

Adjust tests after #7956

761b8df

mischnic mentioned this pull request May 22, 2022

Fix broken hoist unit tests and run them on CI #8123

Merged

marcins mentioned this pull request Jul 5, 2022

Incorrect code produced with ternaries, imported function calls, and ternaries #8281

Closed

mischnic mentioned this pull request Jan 3, 2023

Imports transformations can break code, including 3rd-party #7125

Closed

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Preserve correct `this` for named/default imports #7956

Preserve correct `this` for named/default imports #7956

mischnic commented Apr 14, 2022 •

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mischnic Apr 14, 2022

parcel-benchmark commented Apr 14, 2022 •

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parcel-benchmark commented Apr 20, 2022

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mischnic commented Apr 21, 2022

mischnic commented May 13, 2022

Preserve correct this for named/default imports #7956

Preserve correct this for named/default imports #7956

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mischnic commented Apr 14, 2022 • edited Loading

Problems

mischnic Apr 14, 2022

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parcel-benchmark commented Apr 14, 2022 • edited Loading

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parcel-benchmark commented Apr 20, 2022

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mischnic commented Apr 21, 2022

mischnic commented May 13, 2022

Preserve correct `this` for named/default imports #7956

Preserve correct `this` for named/default imports #7956

mischnic commented Apr 14, 2022 •

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parcel-benchmark commented Apr 14, 2022 •

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