Narrow Zero arithmetic methods to reduce invalidations

[oameye]

Summary

• Narrow +(x::Any, ::Zero), *(::Zero, ::Any), -(x::Any, ::Zero),
  and /(::Zero, x::Any) from ::Any to Number, AbstractArray, and AbstractMutable
• Moves AbstractMutable methods to dispatch.jl (where the type is defined)
• All existing tests pass

Motivation

Loading MutableArithmetics causes 1,489 method invalidations. After this PR: 1,317 (-172).

The remaining MA-owned invalidations (462) are from MutatingStepRange <: OrdinalRange which is inherent to subtyping OrdinalRange and not addressable by type narrowing. The rest (855) come from SparseArrays/Test stdlibs.

Before (v1.6.7 released)

Method	Invalidations
+(x::Any, ::Zero)	446
step(r::MutatingStepRange)	429
*(::Zero, ::Any)	56
iterate(r::MutatingStepRange, i)	30

After (this PR)

Method	Invalidations
step(r::MutatingStepRange)	429 (unchanged — inherent to OrdinalRange subtyping)
iterate(r::MutatingStepRange, i)	30 (unchanged)
+(x::Number, ::Zero)	0
*(::Number, z::Zero)	0

The Zero +/*/-// invalidations are fully eliminated by this PR. The MutatingStepRange invalidations remain but are a separate issue.

How to reproduce

In a fresh Julia session:

using SnoopCompileCore
invs = @snoop_invalidations begin
    using MutableArithmetics
end
using SnoopCompile
using SnoopCompile: countchildren
trees = invalidation_trees(invs)
trees = filter(t -> countchildren(t) > 0, trees)
sort!(trees; by=countchildren, rev=true)
println("Total invalidated methods: ", sum(countchildren, trees))
for t in trees
    println("  $(countchildren(t)) children — ", t)
end

Test plan

• All existing MutableArithmetics tests pass
• Invalidation count verified with SnoopCompile before/after

[codecov]

Codecov Report

❌ Patch coverage is 57.89474% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.40%. Comparing base (6ca6d1b) to head (ebb9ae6).
⚠️ Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
src/rewrite.jl	61.53%	5 Missing ⚠️
src/dispatch.jl	50.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #348      +/-   ##
==========================================
- Coverage   91.79%   91.40%   -0.40%     
==========================================
  Files          23       23              
  Lines        2292     2304      +12     
==========================================
+ Hits         2104     2106       +2     
- Misses        188      198      +10     

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[odow]

This seems reasonable, but @blegat might need to chime in. I'll look into the allocation issues in a separate PR.

[nsajko]

👏

[oameye]

:)

[odow]

This broke PowerModels: https://github.com/lanl-ansi/PowerModels.jl/actions/runs/23859045899/job/69560323741?pr=994

I'll make a fix

[oameye]

Maybe we can add integration tests for downstream packages to CI?

[blegat]

Yes, we have something similar for MathOptInterface

[oameye]

#358

[blegat]

The MutatingStepRange step range invalidations are a bit unfortunate. Actually I developed it more because I was curious to make it work but I don't know if any package is using it, I should have probably developed it in a separate package, but that would be breaking now... (in practice maybe not too breaking if no one is using it though)