AllocCheck false positives on macOS ARM with Julia 1.12+

[ChrisRackauckas-Claude]

Summary

AllocCheck tests report false positive allocations on macOS ARM (aarch64) with Julia 1.12+. This was discovered in PR #54.

Environment

• Platform: macOS ARM (aarch64) - GitHub Actions macos-latest runner
• Julia Version: 1.12.4 (and likely all 1.12.x)
• AllocCheck Version: 0.2.3

Observed Behavior

Every @check_allocs wrapped function reports exactly 1 allocation:

@check_allocs function encountered 1 errors (1 allocations / 0 dynamic dispatches).

This affects all allocation tests:

• hasportion checks (6 tests)
• isscimlstructure checks (2 tests)
• canonicalize checks (4 tests)

Expected Behavior

These functions should report 0 allocations, as they do on:

• ✓ Linux (all Julia versions)
• ✓ Windows (all Julia versions)
• ✓ macOS with Julia LTS (1.10.x)

Current Workaround

Tests are skipped on macOS ARM + Julia 1.12+ in test/alloccheck/alloc_tests.jl:

const SKIP_ALLOCCHECK = Sys.isapple() && Sys.ARCH == :aarch64 && VERSION >= v"1.12"

Investigation Needed

1. Determine if this is an AllocCheck.jl bug or Julia 1.12 ARM codegen issue
2. Check if issue exists in Julia nightly/pre-release
3. File upstream issue to AllocCheck.jl or Julia if appropriate
4. Re-enable tests once upstream fix is available

Related

• PR Add missing Input and Initials methods for AbstractArray #54 - Added workaround
• PR Skip AllocCheck tests on macOS due to ARM compatibility issues #57 / Revert "Skip AllocCheck tests on macOS due to ARM compatibility issues" #58 - Previous attempt to skip all macOS (too broad)

CI Logs

From run https://github.com/SciML/SciMLStructures.jl/actions/runs/20852600937:

• Job: Tests (1, macos-latest, nopre)
• 11 errors, all from AllocCheck reporting 1 allocation