major: replace `ts-loader` with swc #926

kwonoj · 2022-05-11T23:43:18Z

Breaking Changes

No more type checking, run tsc instead
No more emit of .d.ts files, run tsc instead

Description

PR reattempt #777 with updated dependencies, as well as fixing few immediate code paths to pass existing tests. There are few tests removed, related with ts-error fixtures which is redundant now as swc doesn't run type check while compiling.

Some of fixtures has changed its output mostly due to differences between how swc / tsc emits transformed data. I read it manually and looks like it's non-breaking changes, but still need some eyes.

Closes Major: use swc-loader for TypeScript compilation #777

styfle · 2022-05-26T19:10:38Z

Thanks for the PR!

I've testing on real repos here:

This needs further investigation before we land since its not clear why the require() in TS behaves differently

kwonoj · 2022-05-26T19:11:44Z

its not clear why the require() in TS behaves differently

Agreed, somehow only on swc it try to replace it into bundled require logic. I may need further digging to find out reason.

styfle · 2022-07-26T21:04:19Z

@kwonoj I found a bug where the .d.ts files are not emitted with ncc even thought the tsconfig.json has "declaration": true. You can see this had to be changed in vercel/vercel af779ab

kwonoj · 2022-07-26T21:12:03Z

even thought the tsconfig.json has "declaration": true

SWC does not have capability to emit type declaration, this would be (somewhat) expected behavior in this changes, since PR entirely replaces typescript into SWC.

Should we preserve type declaration emission feature? if that's the case, sounds like that's a hard blocker to push SWC for ncc.

styfle · 2022-07-27T13:19:05Z

@kwonoj Hmm, I think replacing tsloader with swc is a fair tradeoff to losing .d.ts since swc is 2x faster in vercel/vercel and vercel/next.js. In the cases we need .d.ts, we can run the slower tsc to generate.

Please update this PR to fix the conflicts and then we can merge, thanks!

styfle · 2022-07-27T23:07:25Z

test/cli.js

-  },
-  {
-    args: ["run", "-t", "test/fixtures/with-type-errors/ts-error.ts"],
-    expect: { code: 0 }


Why were these 3 tests removed?

These tests are specific to verify tsc to fail if given typescript file contains error: for example, test verifies output

code === 1 && stderr.toString().indexOf('ts-error.ts(3,16)') !== -1

to check tsc's error message contains error line to 3:16 where it have type-related error:

//3:16 points 'Y', since there's no corresponding types function p (x: Y) {

which doesn't have any meaningful behavior in swc as it strips out typescript and does not emit any type check failures.

Ok so to be clear, this PR introduces another breaking change: no more type checking?

Yes, it removes out of the box support from running ncc. If we are considering that is a mandatory feature we need to support, I'm afraid it's not achievable via swc.

Ok I update the PR title and description to mention this is semver major and has breaking changes.

Also, it seems there are still failing tests

Huh, weird that only subset of node.js 16 CI's failing. I'll try to peek.

SukkaW · 2022-07-28T14:47:47Z

its not clear why the require() in TS behaves differently

Agreed, somehow only on swc it try to replace it into bundled require logic. I may need further digging to find out reason.

@kwonoj @styfle

FYI, the following code behaves differently in tsc and swc:

// a.js
console.log('a')

// c.js
console.log('c')

// main.js
import a from './a'
console.log('b')
import b from './c'

To be fully compliant with the ESM spec, main.js should yield a c b, but with tsc it will yield a b c.

I don't know if it is the case, so I will raise it here.

kwonoj · 2022-07-28T14:49:25Z

To be fully compliant with the ESM spec, main.js should yield a c b, but with tsc it will yield a b c.

This is true, but afaik the issue in here I observed was not this one.

kwonoj · 2022-07-28T22:44:58Z

@styfle Looks like CI failures are flaky, need additional investigation.

Currently PR passes all the jobs, but the last commit is dummy (fe3837b) which only increases timeout + console.out for stdout/err compare to previous commit failed on some jobs.

src/index.js

cb1kenobi · 2022-07-29T05:22:38Z

I'm not sure what's going on, but I'm seeing a huge performance regression. I have a super small test package with a src/index.ts (contains only 1 exported function) and src/types.ts (contains 3 tiny interfaces). My package is an ESM package: "type": "module".

The latest ncc v0.34.0 can consistently build my package in about 1.5-2 seconds. Command is ncc build src/index.ts --minify. I get type checking and type definition files.

➜  myncctest git:(master) ✗ rm -rf dist && time pnpm run build

> [email protected] build /home/chris/projects/myncctest
> ncc build src/index.ts --minify

ncc: Version 0.34.0
ncc: Compiling file index.js into ESM
ncc: Using [email protected] (local user-provided)
0kB  dist/package.json
0kB  dist/types.d.ts
0kB  dist/index.d.ts
1kB  dist/index.js
1kB  [1404ms] - ncc 0.34.0
pnpm run build  2.95s user 0.14s system 166% cpu 1.854 total

With this PR, it consistently takes 7-12 seconds. Command is identical to above: ncc build src/index.ts --minify. I don't get type checking or type definition files.

➜  myncctest git:(master) ✗ rm -rf dist && time pnpm run build

> [email protected] build /home/chris/projects/myncctest
> ncc build src/index.ts --minify

ncc: Version 0.34.0
ncc: Compiling file index.js into ESM
0kB  dist/package.json
1kB  dist/index.js
1kB  [598ms] - ncc 0.34.0
pnpm run build  38.72s user 0.27s system 388% cpu 10.030 total

Setting the --target es2020 has no effect on the performance. Omitting --minify does shave off around 1 second.

My test set up is WSL (Ubuntu) on Windows 11, Node 16.14.2.

On the plus side, the PR produces the exact same output as the latest ncc, so my package works as expected.

kwonoj · 2022-07-29T05:45:35Z

performance regression

The only thing I can think of is warmup time to compile wasm modules (@swc/wasm), but that probably won't take those huge time unless we spawn bunch of different process and each of them compiles wasm binary.

src/index.js

SukkaW · 2022-07-29T06:28:32Z

src/index.js

-      if(curPath.endsWith(".d.ts")) {
-        const outDir = tsconfig.compilerOptions.outDir ? pathResolve(tsconfig.compilerOptions.outDir) : pathResolve('dist');
+      if (curPath.endsWith(".d.ts")) {
+        const outDir = compilerOptions?.compilerOptions?.outDir ? pathResolve(compilerOptions.compilerOptions.outDir) : pathResolve('dist');


What is compilerOptions?.compilerOptions for?

The latest commit resolves the problem. The review can be marked as resolved now.

SukkaW · 2022-08-10T18:32:06Z

src/index.js

+    tsconfig = JSON5.parse(contents);
+    const baseUrl = tsconfig.compilerOptions.baseUrl;
+    resolveModules.push(pathResolve(dirname(configPath), baseUrl));
+  } catch (e) { }


Should we show a warning message about missing/malformed tsconfig.json here, since compilerOptions would be an empty object and the default swc option would be used?

We didn't warn anything in any case https://github.com/vercel/ncc/pull/926/files#diff-bfe9874d239014961b1ae4e89875a6155667db834a410aaaa2ebe3cf89820556L136 , I'd consider this is failsafe same as before.

kwonoj · 2022-08-10T19:21:49Z

@styfle I've updated PR and resolved most, but can't understand test failures on the ci (https://github.com/vercel/ncc/runs/7774142054?check_suite_focus=true#step:9:303)

This doesn't happen in local somehow
weirdly, coverage seems passing (https://github.com/vercel/ncc/pull/926/files#diff-3eab028f3e7e1b3e18c3c9ab79d0a3a208aa01dea4ee5d4a9234347cc7dde2dcR4) but only normal test emits different output

any possible suggestion to dig / fix this?

styfle · 2022-08-10T19:28:40Z

src/loaders/swc-loader.js

@@ -0,0 +1,110 @@
+// Source code from https://github.com/swc-project/swc-loader/blob/master/src/index.js
+// with the following changes:
+// - swapped out `@swc/core` for `@swc/wasm`


Any reason to use @swc/wasm instead of @swc/core? Seems like this was the cause of the slowdown that @cb1kenobi mentioned in #926 (comment)

Yes, see comment (#926 (comment)) for the explanation.

Honestly, I do not know the exact reason. Previous work in here was using it (https://github.com/vercel/ncc/pull/777/files#diff-8c08ac17cfa691b1772e338822ad7b9cada2a78c0851239d4af55c561c943001R3), and per https://github.com/vercel/ncc/pull/777/files#diff-a992dd64a8c626fedc95d613f43602b91f6dc6339893afaf405dc05fa13c9ceaR96 I only could guess per-platform native binaries are not working well with how ncc works.

FWIW, I rebooted and pulled the latest and build times have dropped from 10 seconds down to 5.5 seconds on average. Mind you the latest ncc release builds in around 2 seconds, so there is definitely a performance regression.

styfle · 2022-08-10T19:30:28Z

test/cli.test.js

-  it(`should execute "ncc ${(cliTest.args || []).join(" ")}"`, async () => {
-    const ps = fork(join(__dirname, file), cliTest.args || [], {
+describe('cli', () => {
+  it.each(cliTests)('should execute ncc $args', async ({ args, env, expect: e, timeout }) => {


Anything change here or is this just formatting?

Formatting only to use jest's built in it.each, which provides better ergonomics / outputs.

I just wasn't sure if this could cause issues with the failing tests but seems unrelated

I believe this shouldn't affect test emission. Also actual failure is unit, cli.test seems passing fine.

This part seems concerning:

- module.exports = eval("require")("../../../../../../../.././module"); + module.exports = eval("require")("../../../../../../../../.././module");

https://github.com/vercel/ncc/runs/7774142054?check_suite_focus=true#step:9:366

That seems like its incorrect

Just for the update purpose - I tried a couple like cache clean and some others, but so far no luck. I'll try to reattempt when I have some time.

@kwonoj I can reproduce locally (macOS + Node.js 16.17.0) by checking out your branch and running

yarn install yarn build yarn test

I tried various, but really stuck with test result inconsistences between local to CI / other machines. It is possible my machine have some weird setup cauing problems, but without figuring it out I can't reliably say PR is ready to go.

Do you have docker locally? You could try cloning this branch in a docker container to see if that reproduces.

I don't think I have a commercial license to install docker on the work machines. I'll think about a few, however I'm very curious why this only (yet) occurs on my machine. Wiping out whole repo & reclone even didn't make changes.

kwonoj requested review from styfle and Timer as code owners May 11, 2022 23:43

SukkaW mentioned this pull request May 24, 2022

Enable externalHelpers when pre compiling Next.js' code vercel/next.js#37164

Merged

styfle mentioned this pull request May 25, 2022

chore(deps-dev): bump ts-loader from 8.3.0 to 9.3.0 #921

Merged

Timer marked this pull request as draft June 15, 2022 04:11

Timer removed their request for review June 15, 2022 04:11

styfle changed the title ~~feat(loaders): replace tsloader into swc~~ major(loaders): replace tsloader with swc Jul 27, 2022

kwonoj force-pushed the feat-swc branch 3 times, most recently from 2615a20 to dd6053b Compare July 27, 2022 17:51

styfle changed the title ~~major(loaders): replace tsloader with swc~~ major(loaders): replace ts-loader with swc Jul 27, 2022

styfle changed the title ~~major(loaders): replace ts-loader with swc~~ major: replace ts-loader with swc Jul 27, 2022

styfle reviewed Jul 27, 2022

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kwonoj force-pushed the feat-swc branch from a72c5f8 to fe3837b Compare July 28, 2022 22:24

styfle approved these changes Jul 28, 2022

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styfle requested review from TooTallNate, ijjk, EndangeredMassa, javivelasco and cb1kenobi July 28, 2022 23:56

SukkaW reviewed Jul 29, 2022

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SukkaW reviewed Jul 29, 2022

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kwonoj added 5 commits August 10, 2022 09:25

feat(loaders): replace tsloader into swc

48cffc9

test(unit): update test fixtures

c7d97b1

test(fixtures): remove redundant ts error tests

8536da2

test(cli): update cli tests

92f43d1

build(package): bump up dependencies

0b14cec

kwonoj force-pushed the feat-swc branch from fe3837b to 0b14cec Compare August 10, 2022 16:28

fix(ncc): correct few compiler options

c46c5ca

SukkaW reviewed Aug 10, 2022

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kwonoj force-pushed the feat-swc branch from 37a806f to a1be9eb Compare August 10, 2022 19:01

test(ncc): update fixtures

93ea727

kwonoj force-pushed the feat-swc branch from a1be9eb to 93ea727 Compare August 10, 2022 19:12

styfle reviewed Aug 10, 2022

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javivelasco removed their request for review August 12, 2022 12:01

SukkaW mentioned this pull request Sep 27, 2023

add esbuild for bundling next runtime vercel/next.js#55997

Closed

EndangeredMassa removed request for EndangeredMassa and cb1kenobi April 3, 2024 19:03

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major: replace `ts-loader` with swc #926

major: replace `ts-loader` with swc #926

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major: replace ts-loader with swc #926

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major: replace ts-loader with swc #926

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kwonoj commented May 11, 2022 • edited by styfle Loading

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major: replace `ts-loader` with swc #926

major: replace `ts-loader` with swc #926

kwonoj commented May 11, 2022 •

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