Custom file types in Buildable Folder

I am trying to solve an issue when converting an existing project to use Buildable Folders:

Our current project have some custom file types that have specialized build rules, as described here: https://developer.apple.com/documentation/xcode/creating-build-rules-for-custom-file-types

We previously added each of these file types, to the target's Compile Sources phase and everything was running well.

Now we wish to move these files into a Buildable Folder, but I cannot find a way to make it work ... as only files with a specific file extensions are ever built in a Buildable Folder, and despite having a custom rule for this file type, it seems like Xcode never runs the rule.

Is there some way to tell Xcode to treat specific extensions in a Buildable Folder as source extension?

As a test, if you create a brand new Xcode project, create the build rule that processes the file during the build, and include a source file that should be processed by that rule, what happens? If that doesn't do what you expect starting from a simple new project, then please use Feedback Assistant to attach that project to a report we can look at, and post the FB number here.

— Ed Ford,  DTS Engineer

Hi Ed, thanks for the response

I've created a radar in: https://feedbackassistant.apple.com/feedback/19753533

I've created a new project and can confirm the behavior is easily reproduced and consistent. Files with custom files extensions that have build rules are ignored when they are inside a buildable folder

Custom file types in Buildable Folder
 
 
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