Fix getSignatureAsArrayFor for Julia 1.12 (code_lowered ordering)#72
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On Julia 1.12 code_lowered returns highest-arity first, so [1] was the full method (body is all SlotNumbers) rather than the lowest-arity default-forwarding method. Reading .code[1].args then threw FieldError: Core.SlotNumber has no field args. Select carrier methods by arity instead of list position: max-arity method for argument names, min-arity forwarding call for default values (SlotNumber/Argument means no default, literal means default; a single method means no defaults). Resilient to future code_lowered reorderings. Also replace abstract ::Integer/::Array locals with ::Int/::Vector. Bump to 0.3.1. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
JKRT
approved these changes
Jun 17, 2026
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This is SVAGEN26 (JKRT_CLAUDE), the Claude Code agent account acting on behalf of @JKRT.
Problem
On Julia 1.12,
getSignatureAsArrayForthrowsFieldError: type Core.SlotNumber has no field args. It fires on any@ExtendedFunction/@ExtendedAnonFunctionexpansion (verified viatest/functionExtensionTest.jl).Root cause
The function read default-argument values out of lowered IR via
code_lowered(func)[1].code[1].args[2:end], assuming[1]is the lowest-arity auto-generated forwarding method (f(a) = f(a, defaults...)). On Julia 1.12code_loweredreturns highest-arity first, so[1]is now the full method whose body isCore.tuple(_2, _3, ...)(allSlotNumbers)..code[1]came back a bareCore.SlotNumberand.argsthrew.Fix
Select carrier methods by arity rather than list position:
SlotNumber/Argument= no default, literal = default; a single method = no defaults)Resilient to future
code_loweredreorderings. Also replaced abstract::Integer/::Arraylocals with::Int/::Vector, and bumped the version to0.3.1.Verification
test/functionExtensionTest.jlpasses on Julia 1.12.6 (zero-arg, typed-default, anonymous, and nested-inheritance cases covered).🤖 Generated with Claude Code