content rules from the JS config that are also covered by the automatic source detection should not be migrated to CSS

[philipp-spiess]

This PR changes the migration of content rules in the JS config to CSS codemods.

When a content rule is processed which matches files that are also matched by the automatic content discovery in v4, we do not need to emit CSS for that rule.

Take, for example this v3 configuration file:

import { type Config } from 'tailwindcss'

module.exports = {
  content: [
    './src/**/*.{html,js}', 
    './node_modules/my-external-lib/**/*.{html}'
  ],
} satisfies Config

Provided the base directories match up, the first rule will also be covered by the automatic content discovery in v4 and thus we only need to convert the second rule to CSS:

@import "tailwindcss";
@source '../node_modules/my-external-lib/**/*.{html}';

[philipp-spiess]

• content rules from the JS config that are also covered by the automatic source detection should not be migrated to CSS #14714 👈
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[philipp-spiess]

Yo what is this branch name, let me see if I can truncate this in Graphite 🙈

[adamwathan]

Actually seeing this I think I'd rather just not log anything, it almost reads like the upgrade couldn't be completed and I'm not sure how to say it more clearly without it being too verbose.

[philipp-spiess]

@adamwathan Yeah I think this makes sense.

[adamwathan]

Should we avoid the word "content" for code that's just looking at the modern stuff?

Are these names clear enough?

Suggested change

	function listAutoContentFiles(base: string) {
	let scanner = new Scanner({ detectSources: { base } })
	scanner.scan()
	return scanner.files
	}
	function listSourceContentFiles(source: { base: string; pattern: string }): string[] {
	let scanner = new Scanner({ sources: [source] })
	scanner.scan()
	return scanner.files
	}
	function autodetectedSourceFiles(base: string) {
	let scanner = new Scanner({ detectSources: { base } })
	scanner.scan()
	return scanner.files
	}
	function patternSourceFiles(source: { base: string; pattern: string }): string[] {
	let scanner = new Scanner({ sources: [source] })
	scanner.scan()
	return scanner.files
	}

[philipp-spiess]

Sounds good. I went with content in the first iteration since we are looking at the content array and this is the content field migration, but yeah in terms of v4, the term content does not really exists.