produceWithPatches(draft => nothing) puts the nothing symbol in the patches

[dxinteractive]

🐛 Bug Report

Link to repro

https://codesandbox.io/s/immer-sandbox-forked-7htbs?file=/src/index.ts

To Reproduce

var {produceWithPatches, nothing, enablePatches} = require("immer")
enablePatches(true);
let [newState,patches] = produceWithPatches({abc: 123}, draft => nothing);
// newState is undefined <- correct
patches[0].value === nothing <- incorrect?

Observed behavior

The immer nothing symbol can appear as the value in "replace" patches. Is this right? I thought the purpose of the nothing symbol was to simply give producers a way of differentiating between a mutating producer that implicitly returned undefined, and a returning producer that wants to output undefined as the next state. If that's true then perhaps the nothing symbol should not appear outside the producer itself.

Expected behavior

Patches that are produced setting state to nothing should have a value of undefined.

Environment

• 9.0.2
• I filed this report against the latest version of Immer
• Occurs with setUseProxies(true)
• Occurs with setUseProxies(false) (ES5 only)

[mweststrate]

Confirmed, reproduction: https://codesandbox.io/s/immer-sandbox-forked-fs9n5?file=/src/index.ts

[github-actions]

🎉 This issue has been resolved in version 9.0.4 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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