Deduplicate assets when using Buffer content in emitFile

[patak-dev]

Feature Use Case

Now that vite@4.0.0-alpha.0 is running on Rollup 3. We're checking if we could simplify our custom hashing of assets (we currently do hashing, deduplication, and filenames by hand) to use the standard Rollup asset handling. As an example, here we are hashing and deduplicating by hand before calling emitFile https://github.com/vitejs/vite/blob/cb84f37771fdc424b5656079a4765e7aee74cc25/packages/vite/src/node/plugins/asset.ts#L460.

We're running into an issue when refactoring this code to directly use emitFile because it doesn't deduplicate the file if a Buffer is passed instead of a string. But for Fonts we would also want to have deduplication.

Feature Proposal

In our case, by default we have [hash] in assetsFileNames, so if strings and Buffers would be deduplicated using hashes there wouldn't be a noticeable performance penalty.

I imagine this feature should be optional if a performance regression must be avoided for the case of assetsFileNames without [hash].

[rollup-bot]

This issue has been resolved via #4712 as part of rollup@3.3.0. You can test it via npm install rollup.