🌱 Part 5: Reduce number of variable sources. Final cleanup

[m1kola]

Description

Spliting #460 into smaller chunks.

In this PR I replace controller variable source with an implementation containing a bunch of function calls (from parts 1-4). I also remove old variable sources and related tests

Closes #437

Reviewer Checklist

• API Go Documentation
• Tests: Unit Tests (and E2E Tests, if appropriate)
• Comprehensive Commit Messages
• Links to related GitHub Issue(s)

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (7e321b4) 85.30% compared to head (c73b5a6) 83.69%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #501      +/-   ##
==========================================
- Coverage   85.30%   83.69%   -1.61%     
==========================================
  Files          23       20       -3     
  Lines         898      822      -76     
==========================================
- Hits          766      688      -78     
- Misses         91       92       +1     
- Partials       41       42       +1     

Flag	Coverage Δ
e2e	63.86% <80.00%> (-2.17%)	⬇️
unit	78.59% <80.00%> (-1.46%)	⬇️

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

Files	Coverage Δ
internal/resolution/variablesources/bundle.go	100.00% <ø> (ø)
...al/resolution/variablesources/bundle_uniqueness.go	100.00% <ø> (ø)
internal/controllers/variable_source.go	68.75% <80.00%> (-3.98%)	⬇️

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

[ncdc]

Maybe take a look at https://freshman.tech/snippets/go/concatenate-slices/, specifically the section "Concatenating multiple slices at once", as a way to do this more efficiently?

[m1kola]

@ncdc the above works when we want to concatenate slices of the same type. Here we have slices of multiple different types all of which implement deppy.Variable interface and we need to create a slice of deppy.Variables. I don't think it will work here.

I considered doing pre-allocation like this:

result := make([]deppy.Variable, 0, len(requiredPackages)+len(installedPackages)+len(bundles)+len(bundleUniqueness))

But decided not to go with it. It still requires a loop with an append. Also It seems brittle: I can definitely see myself not updating the make call with a new variable when adding another loop. But it avoids extra allocations.