I work on an app that has a feature in debug builds where we

Question

I work on an app that has a feature in debug builds where we dump the entire view hierarchy of the main window in certain cases e g for crash reports or manually via a special debug menu This can be really helpful for figuring out the state of the UI when things go wrong Is it possible to do this with Compose What would that look like One option would be to walk the semantics tree although I m not sure that would contain enough information for debugging the UI itself Another option would be getting access to the root `LayoutNode` and walking the node tree but many Composables just wrap other Composables and don t have their own `LayoutNode`s modifiers are often contributed from multiple composables for a single node etc so that s not ideal either I ve seen some work being done for Android Studio tooling around extracting some data about stuff like this by inspecting the slot table directly Would it be reasonable to request a public API for exposing that parsing in debug builds

Vinay Gaba · Answer

I ve been thinking about a really similar use case where I need more information about the hierarchy and I strongly agree that we need a way to have that information available +100 to this

Zach Klippenstein (he/him) [MOD] · Answer

In dev16 the tooling module has an `asTree ` extension method on `SlotTable` and this seems to return more than enough information for this kind of use case

Zach Klippenstein (he/him) [MOD] · Answer

If view attribute inspection is enabled in dev tools it even includes source locations for all the calls

Vinay Gaba · Answer

this is amazing pray skin tone 3

Andrew Neal · Answer

Yeah man Really nice

jim · Answer

If this is intended for debug only what is the problem with reflection

Zach Klippenstein (he/him) [MOD] · Answer

Only that it s harder to maintain since it doesn t fail with compiler errors and private APIs are more likely to change without documentation I would totally be fine using reflection to solve this it would just be more work and a small public API would be nice to have if possible

jim · Answer

Ok makes sense worth considering We generally like to provide APIs for anything we do ourselves but this situation has some interesting considerations We would not want such an API to be available outside of extenuating circumstances like debug mode If it s a real API we would need to consider API stability and I m not sure if we want to officially support such an API and we certainly don t want to give the API any sort of credibility as being a reasonable way of doing something in a production app So it requires some thinking on our end

Zach Klippenstein (he/him) [MOD] · Answer

I can file a feature request if it s helpful to track this I don t have any more specific ideas at this point either but wanted to get it on your radar

Zach Klippenstein (he/him) [MOD] · Answer

A couple things that could be immediately useful here 1 A way to turn on source information programmatically ideally temporarily for a composition that doesn t involve connecting the Layout Inspector or turning on Debug View Attributes in dev options This seems like something that would only be available in debug builds so might not help for debugging production crashes but could be helpful for local development 2 Some way to identify data from common foundational things like `remember` in the output from `SlotTable asTree ` besides just matching the group name which seems pretty brittle any function could call itself remember Maybe this is an XY question the reason this could be helpful is that it could serve as a simple heuristic for data that might represent state that the developer cares about and would want to see in a dump of the current composition Still playing around with other ways to guess this stuff and try to prevent a slightly less overwhelming view of the composition so hoping I ll find another way to do this