Fix type conversion and type instability

[huiyuxie]

Third fix patch for #2128.

[github-actions]

Review checklist

This checklist is meant to assist creators of PRs (to let them know what reviewers will typically look for) and reviewers (to guide them in a structured review process). Items do not need to be checked explicitly for a PR to be eligible for merging.

Purpose and scope

• The PR has a single goal that is clear from the PR title and/or description.
• All code changes represent a single set of modifications that logically belong together.
• No more than 500 lines of code are changed or there is no obvious way to split the PR into multiple PRs.

Code quality

• The code can be understood easily.
• Newly introduced names for variables etc. are self-descriptive and consistent with existing naming conventions.
• There are no redundancies that can be removed by simple modularization/refactoring.
• There are no leftover debug statements or commented code sections.
• The code adheres to our conventions and style guide, and to the Julia guidelines.

Documentation

• New functions and types are documented with a docstring or top-level comment.
• Relevant publications are referenced in docstrings (see example for formatting).
• Inline comments are used to document longer or unusual code sections.
• Comments describe intent ("why?") and not just functionality ("what?").
• If the PR introduces a significant change or new feature, it is documented in NEWS.md with its PR number.

Testing

• The PR passes all tests.
• New or modified lines of code are covered by tests.
• New or modified tests run in less then 10 seconds.

Performance

• There are no type instabilities or memory allocations in performance-critical parts.
• If the PR intent is to improve performance, before/after time measurements are posted in the PR.

Verification

• The correctness of the code was verified using appropriate tests.
• If new equations/methods are added, a convergence test has been run and the results
  are posted in the PR.

Created with ❤️ by the Trixi.jl community.

[huiyuxie]

I think it would be the last one but I cannot guarantee.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.42%. Comparing base (67a566c) to head (ba19502).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2243      +/-   ##
==========================================
- Coverage   96.42%   96.42%   -0.00%     
==========================================
  Files         487      487              
  Lines       39345    39344       -1     
==========================================
- Hits        37935    37934       -1     
  Misses       1410     1410              

Flag	Coverage Δ
unittests	96.42% <100.00%> (-<0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ranocha]

Thanks

[ranocha]

The error

Error building `FFTW`: 
ERROR: LoadError: Unable to open libLLVM!

https://github.com/trixi-framework/Trixi.jl/actions/runs/12877053965/job/35900961386?pr=2243#step:7:56

is not related to this PR, we also see it somewhere else. Did somebody report it upstream?

[huiyuxie]

Let me check

[huiyuxie]

https://discourse.julialang.org/t/unable-to-open-libllvm-error-trying-to-create-sysimage-in-1-8-0/86144

The similar issue - BinaryProvider.jl is no longer being maintained.