[CI Broken] Upstream GeometricIntegrators.jl failures on all Julia versions

[ChrisRackauckas-Claude]

Summary

CI is failing on all Julia versions (LTS 1.10, 1.11, 1.12) due to issues in the upstream dependency GeometricIntegrators.jl.

Failure Analysis

Julia 1.10 (LTS)

TypeError: in Type{...} expression, expected UnionAll, got Type{SimpleSolvers.NonlinearSolver}

Location: ~/.julia/packages/GeometricIntegrators/Yo3w3/src/integrators/rk/integrators_firk.jl:65

Julia 1.11 & 1.12

ArgumentError: invalid type for argument sol in method definition for copy_solution!

Location: ~/.julia/packages/GeometricIntegrators/Yo3w3/src/solutions/atomic_solution.jl:32

Root Cause

The failures are in the upstream GeometricIntegrators.jl package (https://github.com/JuliaGNI/GeometricIntegrators.jl), not in this package. GeometricIntegratorsDiffEq.jl cannot function until GeometricIntegrators.jl is fixed for:

1. Julia 1.10 - Type expression issue in integrators_firk.jl
2. Julia 1.11/1.12 - Method definition issue in atomic_solution.jl

Suggested Actions

1. Check if there's a newer version of GeometricIntegrators.jl that addresses these issues
2. Open an issue on the GeometricIntegrators.jl repository if not already reported
3. Consider pinning to a working version of GeometricIntegrators.jl if one exists

Reference

Discovered via CI health check PR: #43

cc @ChrisRackauckas

[ChrisRackauckas]

Fix this by trying to use the latest GeometricIntegrators.jl version and fix the wrapper code here. Assume that GeometricIntegrators.jl is fine.

[ChrisRackauckas-Claude]

Issue Resolution

I've successfully fixed the CI failures reported in this issue.

Root Cause

The issue was not in the upstream GeometricIntegrators.jl package as originally suspected. The actual problem was a stale import in our wrapper code:

• The code imports isinplace from SciMLBase
• However, isinplace is only used as a type parameter in the function signature (AbstractODEProblem{uType, tType, isinplace})
• The imported function itself was never called, making it a stale import
• This caused the ExplicitImports hygiene test to fail

Solution

Removed the unused isinplace import from the using SciMLBase statement in src/GeometricIntegratorsDiffEq.jl.

Testing

All tests now pass locally on:

• ✅ Julia 1.10 (LTS)
• ✅ Julia 1.11
• ✅ Julia 1.12

Pull Request

Created PR #57 with the fix. The change is minimal (one line) and all tests pass.

The good news is that the current version of GeometricIntegrators.jl (v0.15.4) works fine with all Julia versions - there were no actual compatibility issues with the upstream package.

cc @ChrisRackauckas