JS hash fails to change when asset URL changes

[jakearchibald]

• Rollup Version: 1.32.0
• Operating System (or Browser): OSX
• Node Version (if applicable): v12.16.1
• Link to reproduction: https://github.com/jakearchibald/rollup-hash-bug

In this demo, both src1 and src2 are built. The only difference between the two is the content of some-asset.txt.

Expected Behavior

The hash of both the JS and asset is different between builds, since the JS imports the asset, the content of its file has changed.

Actual Behavior

Only the hash of the txt file changes.

[lukastaegert]

Another important test case for a reimplemented hashing algorithm.

[jakearchibald]

This also impacts modules containing import.meta.ROLLUP_FILE_URL_referenceId that point to chunks.

With assets, you can kinda work around it with augmentChunkHash, using the buffer of the asset to augment the hash, but that isn't really possible with chunks, since they have dependencies of their own.

[sebastianseilund]

A workaround that seems to work for me is to add a hash of the asset's source as a JS comment together with import.meta.ROLLUP_FILE_URL_referenceId. So instead of the following from https://github.com/jakearchibald/rollup-hash-bug/blob/master/lib/asset-plugin.js :

return `export default import.meta.ROLLUP_FILE_URL_${this.emitFile({
  type: 'asset',
  source: await fs.readFile(realId),
  name: basename(realId),
})}`;

Do this instead:

import {createHash} from 'crypto'
// ...
const source = await fs.readFile(realId)
const referenceId = this.emitFile({
  type: 'asset',
  source,
  name: basename(realId),
})
const hash = createHash('sha256').update(source).digest('hex').slice(0, 8)
return `export default import.meta.ROLLUP_FILE_URL_${referenceId}; /* asset-hash:${hash} */`

Rollup will now consider the importing JS module's source as being different since the comment depends on the asset source hash, causing a different JS hash (which is what we want). The JS comment is stripped by minification later (if using).

[lukastaegert]

Fix at #4543

[rollup-bot]

This issue has been resolved via #4543 as part of rollup@3.0.0-7. Note that this is a pre-release, so to test it, you need to install Rollup via npm install rollup@3.0.0-7 or npm install rollup@beta. It will likely become part of a regular release later.

[rollup-bot]

This issue has been resolved via #4543 as part of rollup@3.0.0-8. Note that this is a pre-release, so to test it, you need to install Rollup via npm install rollup@3.0.0-8 or npm install rollup@beta. It will likely become part of a regular release later.

[rollup-bot]

This issue has been resolved via #4543 as part of rollup@3.0.0. You can test it via npm install rollup.