Description

Analysis at #44579

Rather than throwing an assertion here, this should be a runtime error. This also makes it clearer why the load failed and properly uses the error handling mechanisms we have in place.

/cc @slightfoot @escamoteur

Related Issues

Fixes #44579

Tests

I added the following tests:

Tests that we throw a state error when trying to load an empty file.

Checklist

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Breaking Change

Did any tests fail when you ran them? Please read Handling breaking changes.

• No, no existing tests failed, so this is not a breaking change.