Make struct immutable

[icweaver]

Closes #34

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.28%. Comparing base (7ccd42d) to head (99e1e03).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #35   +/-   ##
=======================================
  Coverage   74.28%   74.28%           
=======================================
  Files           8        8           
  Lines         140      140           
=======================================
  Hits          104      104           
  Misses         36       36           

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[cgarling]

Great, thanks!

[icweaver]

I might have spoken too soon 😅. 1 test is currently breaking in our resampling PR. Will take a quick look

[icweaver]

Ahhh, ok. This line, for example, tries to replace a mutable field with another one, which fails as expected when spec is made immutable

https://github.com/JuliaAstro/Spectra.jl/blob/46dfee47702c5b896dd05648e8e6fffd1b55e769/test/transforms/resample.jl#L22

I think sprinkling in a dot, e.g., spec.flux .= Spectra.flux(spec_new) , won't really save us here since we can't guarantee that the new array will be the same size.

Would it make sense to just return a new immutable struct instead?

[cgarling]

Thanks for checking, sounds like there's an issue in the test code, not in the package code?

I think for resampling as per #26 we want to return a new instance rather than mutating an existing one. I'm not sure the resample! methods as defined in the test file make sense here

[icweaver]

sgtm! Dropped in the other PR and will go ahead and merge here