Watch package.json, add version to the bundle - rollup

Question

I'm bundling a library with rollup and trying to add a version from package.json into the code itself.
Relevant bits of rollup config:
import pkg from './package.json'
output: [{
footer: `foo.version = '${pkg.version}'`
}]
The problem is, it's not getting updated with hotreload/watch. (rollup -w -c rollup.development.config.js')
Tried a few things:
using output plugins: they don't run again on watch
doing a dynamic import in the footer: not running again either
custom watcher plugin to include package.json: this triggers reload, but still not running the code that would read the updated value (plugins or footer)
Is there a way to do this? I wouldn't mind doing a full rebuild when package.json changes, but I'd like to avoid restarting the process manually. I'm frankly confused how such a simple thing can be this complicated.
Thanks
EDIT:
The version is not updated even when I do this:
const getVersion = () => ({
async renderStart () {
const data = await import('./package.json')
console.log('version: ' + data.version)
}
})
export default async () => ({
output: [{
plugins: [getVersion()]
}]
})
Thought it's a cache, so I tried invalidating it with ?date=' + Date.now(), but that just gives me Error: Cannot find module './package.json?test=1652969298057'. Seems like rollup is using require :(

Answer 1

Figured it out:
rollup.config.js
import glob from 'glob'
import path from 'path'
import fs from 'fs'
const watcher = (globs) => ({
buildStart () {
for (const item of globs) {
glob.sync(path.resolve(item)).forEach((filename) => { this.addWatchFile(filename) })
}
}
})
const updateVersion = () => ({
renderStart (outputOptions, inputOptions) {
outputOptions.footer = () => `library.version = ' + ${JSON.parse(fs.readFileSync('package.json', 'utf8')).version}'`
}
})
export default {
plugins: [
watcher(['package.json'])
],
output: [{
plugins: [
updateVersion()
]
}]
}