[engineering] sourcemap issues

[tmm1]

1. source files are duplicated inside sourcemap

❯ npm run gulp compile-build-without-mangling

❯ cat out-build/main.js.map | jq .sourceRoot
"file:///Users/tmm1/code/vscode/src"

❯ cat out-build/main.js.map | jq .sources
[
  "file:///Users/tmm1/code/vscode/src/main.ts",
  "main.ts"
]

2. duplicated paths are further corrupted during minification

❯ npm run gulp minify-vscode

❯ cat out-vscode/main.js.map | jq '.sources[0,1]'
"../file:/Users/tmm1/code/vscode/src/vs/base/common/performance.ts"
"../vs/base/common/performance.ts"

❯ cat out-vscode-min/main.js.map | jq '.sources[0,1]'
"./file:/Users/tmm1/code/vscode/src/vs/base/common/performance.ts"
"vs/base/common/performance.ts"

[tmm1]

It appears atleast some of these issues are in upstream esbuild evanw/esbuild#4015 (comment)

However most of those were fixed in 0.25, and we are already using 0.25.0 as of #240433. The issues are still occurring as shown above.

[tmm1]

If I revert back to esbuild 0.23.0, the behavior is as so:

❯ npm run gulp core-ci-pr
❯ cat out-vscode/main.js.map | jq '.sources[0,1]'
"vs/base/common/file:/Users/tmm1/code/vscode/src/vs/base/common/performance.ts"
"vs/base/common/vs/base/common/performance.ts"

[bpasero]

Thanks for the report, opening up for help wanted. Our main VS Code esbuild step is here:

vscode/build/lib/optimize.ts

Lines 205 to 209 in 080c694

	export function bundleTask(opts: IBundleESMTaskOpts): () => NodeJS.ReadWriteStream {
	return function () {
	return bundleESMTask(opts.esm).pipe(gulp.dest(opts.out));
	};
	}

and if minification is enabled:

vscode/build/lib/optimize.ts

Line 211 in 080c694

export function minifyTask(src: string, sourceMapBaseUrl?: string): (cb: any) => void {

As for the mangling, that is done here:

vscode/build/lib/compilation.ts

Line 137 in 080c694

let ts2tsMangler = new Mangler(compile.projectPath, (...data) => fancyLog(ansiColors.blue('[mangler]'), ...data), { mangleExports: true, manglePrivateFields: true });