fix: clean coverage-c8 tmp before reporting (fix #1917)

[sun0day]

fix #1917

Clean tmp dir before coverage-c8 report each time.

Same as:

https://github.com/bcoe/c8/blob/7f1069dcce6821a6794557b39d6a13f620c64bad/bin/c8.js#L31-L35

[AriPerkkio]

There should be no need to re-implement this logic. It is already done in clean function.

vitest/packages/coverage-c8/src/provider.ts

Lines 35 to 41 in 5b190e8

	async clean(clean = true) {
	if (clean && existsSync(this.options.reportsDirectory))
	await fs.rm(this.options.reportsDirectory, { recursive: true, force: true })
	if (!existsSync(this.options.tempDirectory))
	await fs.mkdir(this.options.tempDirectory, { recursive: true })
	}

This function should be called from packages/vitest as it was before 0.22 release. I think it broke somewhere in #1676.

[sun0day]

I'm not sure whether onBeforeFilesRun supports calling async clean. If support, I can change onBeforeFilesRun to call async clean. Besides, I think it's better to handle clean logic inside C8CoverageProvider.

[sun0day]

Or we can call C8CoverageProvider.clean in initCoverageProvider

vitest/packages/vitest/src/node/core.ts

Lines 119 to 127 in 5b190e8

	async initCoverageProvider() {
	if (this.coverageProvider !== undefined)
	return
	this.coverageProvider = await getCoverageProvider(this.config.coverage)
	if (this.coverageProvider) {
	await this.coverageProvider.initialize(this)
	this.config.coverage = this.coverageProvider.resolveOptions()
	}
	return this.coverageProvider

[AriPerkkio]

Coverage provider is instructed to clean here.

vitest/packages/vitest/src/node/core.ts

Line 108 in 5b190e8

await this.coverageProvider?.clean(this.config.coverage.clean)

But it seems that this.coverageProvider has not yet been initialized at this point. This is clearly a bug.

The this.coverageProvider.clean() should be moved so that it is called after this.initCoverageProvider(). Maybe here into start?

vitest/packages/vitest/src/node/core.ts

Lines 148 to 151 in 5b190e8

	async start(filters?: string[]) {
	try {
	await this.initCoverageProvider()
	}

[sun0day]

Alright. I will modify my commit code

[sun0day]

done @AriPerkkio