refactor: eliminate batch

[dai-shi]

Background

Batch (formerly Pending) was introduced a long time ago. The major purpose was to provide an async context (Like AsyncLocalStorage) to hold state concurrently. It was really necessary at some point (before v1?), but after v2 or so, the purpose has been more for organizing store.ts code so that atoms are isolated. Like the store doesn't know about all atoms. However as we introduced #2827 and other PRs, the store now coordinates atoms as the single source of truth, and we had to tweak Batch. #2905 went further. I expected that I could change it towards the designed shape, but #2919 and #2918 didn't work.

Moving forward

If we use the store as the single source of truth, I don't think we need batch. Interestingly, I just noticed that batch isn't used in readAtomState at all. We are just passing it recursively without consuming it. I don't remember when this has changed. This PR is only to eliminate batch, but I have a big picture in mind which is close to #2911, but I'll explore a bit more. The end goal is probably providing a bunch of hooks, so that the ecosystem libraries can do anything on their own risks. There should be more room to minimize the store code, but that will be tackled afterwards.

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commit: c601bd9

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Size Change: -192 B (-0.21%)

Total Size: 91.9 kB

Filename	Size	Change
./dist/esm/vanilla.mjs	4.18 kB	-41 B (-0.97%)
./dist/system/vanilla.development.js	4.27 kB	-40 B (-0.93%)
./dist/system/vanilla.production.js	2.16 kB	-7 B (-0.32%)
./dist/umd/vanilla.development.js	5.67 kB	-10 B (-0.18%)
./dist/umd/vanilla.production.js	2.77 kB	-84 B (-2.94%)
./dist/vanilla.js	5.56 kB	-10 B (-0.18%)

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[dai-shi]

Wait, I might notice some issues. I will continue working on it. Until then, this isn't ready.

[dmaskasky]

Beautiful PR. This is the next evolution of the store code. I had a feeling the store was getting quite bloated with all the batch logic, I'm glad you figured this out.

[dmaskasky]

Is my understanding of the semantic difference between these correct?

1. atomState.n === previousEpochNumber - the version of the atom value or error. Used to determine whether the atom has changed.
2. atomState.x - atom is invalidated, indicates whether the atom value needs to be recomputed.
3. changedAtoms.has(atom) - changedAtoms is a set of atoms where their atom version has changed.

Could we replace ++atomState.n with changedAtoms.add(atom)?

[dai-shi]

Could we replace ++atomState.n with changedAtoms.add(atom)?

Maybe not. n is also used for dependency checking. changedAtom is for write only. Though, I'm not saying what it shows now is ideal. As I noted, there would be many room for improvements, and this is only the first step.

[dai-shi]

/ecosystem-ci run

[github-actions]

Ecosystem CI Output

---- Jotai Ecosystem CI Results ----
{
  "bunshi": "PASS",
  "jotai-devtools": "PASS",
  "jotai-effect": "FAIL",
  "jotai-scope": "PASS"
}

[dai-shi]

/ecosystem-ci run

[github-actions]

Ecosystem CI Output

---- Jotai Ecosystem CI Results ----
{
  "bunshi": "PASS",
  "jotai-devtools": "PASS",
  "jotai-effect": "FAIL",
  "jotai-scope": "PASS"
}

[dai-shi]

Let me confirm that this still fails with jotai-effect.

[dai-shi]

/ecosystem-ci run

[github-actions]

Ecosystem CI Output

---- Jotai Ecosystem CI Results ----
{
  "bunshi": "PASS",
  "jotai-devtools": "PASS",
  "jotai-effect": "FAIL",
  "jotai-scope": "PASS"
}

[dai-shi]

Final status:

• We are happy with this simplified implementation.
• jotai-effect v1 needs to address this change later.
• This is fairly a big rewrite, but more is coming (like feat(core/unstable): expose internals instead of unstable_derive #2911). We need to communicate the status with users with release notes and announcements.