Address potential preview warnings #378
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We currently allow folks to use `prepareDependencies` in the body of a preview, which works great. It does appear that previews have gotten fancier, especially in Xcode 26, where a preview session stays live even during changes to view code. These changes cause the preview body to re-evaluate, triggering `prepareDependencies` all over again, and spitting out a large purple warning into the preview console. The behavior of `prepareDependencies` is to ignore future calls and surface warnings in to catch misuse, but maybe we should only emit these warnings in the application. Preview environments are a bit treacherous as is, with app entry point code leaking into them, and preview trait code executing across multiple previews in a file. And so this branch proposes silencing this warning in previews entirely. Alternatives: - We could shorten the warning to a one-liner. Something like "Xcode Preview: 'prepareDependencies' already called this session. Ignoring." - We could stop showing 'prepareDependencies' as a legit tool for previews and instead push people towards 'withDependencies', though this is not great for ergonomics, especially in non-single entry point systems. Bonus change: This PR also updates the warning about ignoring app entry point dependencies in previews with instructions on how to suppress. But given the above, maybe we actually want to suppress this warning entirely?
It's not super helpful in practice.
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We currently allow folks to use
prepareDependenciesin the body of a preview, which works great. It does appear that previews have gotten fancier, especially in Xcode 26, where a preview session stays live even during changes to view code. These changes cause the preview body to re-evaluate, triggeringprepareDependenciesall over again, and spitting out a large purple warning into the preview console.The behavior of
prepareDependenciesis to ignore future calls and surface warnings in to catch misuse, but maybe we should only emit these warnings in the application. Preview environments are a bit treacherous as is, with app entry point code leaking into them, and preview trait code executing across multiple previews in a file. And so this branch proposes silencing this warning in previews entirely.This PR also removes the warning about ignoring app entry point dependencies in previews, as the warning was not super useful in practice.