Sourcemaps break when using treeshake: 'smallest'

[aleclarson]

It seems when Rollup is used for extra tree-shaking, the sourcemaps no longer trace back to correct positions in the source code. This makes breakpoints effectively useless.

You might be forgetting to feed the sourcemaps into Rollup?

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[xia0hj]

I met this problem too, it might be caused by incorrect use of applySourceMap here

tsup/src/plugin.ts

Lines 156 to 166 in 322cb77

	if (result.map) {
	const originalConsumer = await new SourceMapConsumer(
	parseSourceMap(info.map)
	)
	const newConsumer = await new SourceMapConsumer(
	parseSourceMap(result.map)
	)
	const generator =
	SourceMapGenerator.fromSourceMap(originalConsumer)
	generator.applySourceMap(newConsumer, info.path)
	info.map = generator.toJSON()

correct example: https://github.com/mozilla/source-map/blob/master/test/test-source-map-generator.js#L356-L362

Besides, default output is ./dist/index.js.map. But rollup treeshake sourcemap path is ./out.js.map, result in incorrect sources path src/index.ts. The correct one should be ../src/index.ts

I fixed these 2 bugs in #1069

[aleclarson]

In addition to @xia0hj's PR, there's also this one: #949 (by @hyrious)

I've not tested it myself. Interestingly, it's quite a bit different than @xia0hj's solution.

[github-actions]

🎉 This issue has been resolved in version 8.1.2 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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