`{@debug object}` doesn't fire when `object.property` changes

[Rich-Harris]

Describe the bug

Noticed this while updating the tutorial. This is a breaking change from 4 and makes @debug a bit useless, though I'm not sure if we should fix it or treat it as deprecated

Reproduction

link

[adiguba]

The debug message is also useless since it only displays 'Proxy'...

I think it could be fixed easily by using $.snapshot() on all the variables in console.log().
It may be useless in some cases, but for debugging it is not really annoying I think...

[7nik]

Does @debug has any advantages over $inspect?

[brunnerh]

• Does not cause two logs on every change
• Adds a breakpoint via debugger

[7nik]

1. Looking at all those $inpect problems due to being sync, would it make sense to add $inspect.lazy?
2. You can do

$inspect(foo).with((...args) => {
  console.log(...args);
  debugger;
});

[dummdidumm]

It's not a breaking change per se, because it will work when state is updated as a whole. The question is whether or not @debug should behave like $inspect (i.e. also fire on any changes within), or only when the variable itself is reassigned. I now slightly lean towards aligning the behavior (did lean the other way at first).

[adiguba]

In Svelte 4 @debug already fire on any changes within the object... but of course it's limited by the Svelte 4 model and source-analysis.

Example : https://svelte.dev/repl/8248f009ac7946f9840fa6103f7d2568?version=4.2.19

This is a debugging tool, it should be as responsive as possible IMHO.
(and eventually deprecated for the benefit of $inspect)

[Rich-Harris]

yeah i think snapshotting is probably the right approach