Immer is modifying baseObject and not throwing exception for nested un-draftable objects.

[keepRunning]

🐛 Bug Report

Based on the documentation, object of type 'class' needs to have [immerable] set to true to be handled.
When [immerable] is not set, it should throw an exception.

However, if the baseObject is plain javascript/(class with immerable set to true) and the nested object is un-draftable(class without immerable), then the baseObject itself is modified and returned without exception.

Link to repro

https://codesandbox.io/s/immer-sandbox-error-forked-rry8q

Observed behavior

BaseObject is modified and returned. No exception is thrown.

Expected behavior

Exception should be thrown.

Environment

We only accept bug reports against the latest Immer version.

• Immer version: 9.0.7
• I filed this report against the latest version of Immer
• Occurs with setUseProxies(true)
• Occurs with setUseProxies(false) (ES5 only)

[mweststrate]

That is working as expected, if a class is not marked immerable, it behaves like it would normally do in JavaScript. The fact that it is referred to by a draft is unrelated to that.

[mweststrate]

See also #686, we could warn more explicitly about this, just not landed it so far for the impact it will have.

[keepRunning]

Thanks for the clarification.
It will be difficult for us to adopt immer without a exception failure, as we have a highly nested class structure and multiple developers introducing new changes.