XcodeGen stops generating schemes when using 'preAction' in a project with lots of schemes

Problem Description

My application has over 150 schemes, and I'm attempting to run XcodeGen as a "preAction" in a scheme to simplify the project file to include only the necessary files. Each scheme is targeted for a different client, and each client has their own set of files for customizing the app's appearance. Originally, I had these files in different targets, but due to performance issues in Xcode, I want to keep the project file as lightweight as possible.

The issue is that when running a scheme, in most cases, XcodeGen stops before completing the project generation, and only a few schemes are actually created. I've logged the output to a log file, and all it shows is:

⚙️  Generating plists...
⚙️  Generating project...
⚙️  Writing project...

Additional Information

• XcodeGen Version: 2.37.0

Steps to Reproduce

1. Create a project.yml with more than 150 schemes.
2. Set up a "preAction" in all schemes to run XcodeGen.
3. Execute a scheme.

Expected Behavior

I expect XcodeGen to successfully generate all schemes and finish building the project without interruptions.

Current Behavior

XcodeGen stops before completing the project generation

Start by reproducing the issue with the mentioned project.yml, more than 150 schemes, and XcodeGen invoked through a scheme preAction. Compare the generation output with the expected completion and inspect the project-generation path responsible for writing schemes. Done means XcodeGen completes without stopping and generates all schemes.