What are some telltale clues that would lead you to determine whether or not code and infrastructure were tightly coupled?
By "infrastructure" I mean build processes, package management, and so on. It's naturally tied to the code; the problem is when the code you want to open is mixed in with the code you don't. That's usually pretty obvious.
Gotcha. And from there you would be inclined to review what has been separated from infrastructure/etc for modules to open source (assuming something like "open core" was being followed)?
Your infrastructure is very nearly irrelevant in the grand scheme of things. That tooling is just how you deliver for your own organization, based on your organization's context and needs. It's the launch pad and rocket boosters; you're trying to open up the space shuttle. I've got my own launch pad and so on already.
That said, if you've already factored some non-trade-secret stuff out into its own module that you deliver separately and think of as a dependency in the parts you don't want to open, yes, it's a natural candidate for opening.
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