55 lines
1.6 KiB
Markdown
55 lines
1.6 KiB
Markdown
# UNDF: UNDF-2026-000000352
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## Classification
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| Field | Value |
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|-------------|-------|
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| CWE | CWE-407 Inefficient Algorithmic Complexity |
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| Severity | MEDIUM |
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| Component | `Compiler/src/reinfer.jl:432` |
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| Function | (method order determination — morespecific BFS) |
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| Hot path | Method dispatch ordering — called during type inference for every ambiguous method pair |
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| Status | PATCHED (unit test PASS) |
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## Defect
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Method interference graph BFS uses `visited = Method[]` (Array) with `method3 in visited`
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for cycle prevention. `in` on a Julia Vector/Array is O(V) linear scan:
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```julia
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visited = Method[] # Array — O(V) membership
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push!(visited, method2)
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workqueue = Method[method2]
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while !isempty(workqueue)
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current = pop!(workqueue)
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for k = 1:length(interferences)
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method3 = interferences[k]::Method
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method3 in visited && continue # O(V) per check — CWE-407
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push!(visited, method3)
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push!(workqueue, method3)
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end
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end
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```
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With V methods reachable in the interference graph, total membership checks: O(V²).
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Called during type inference for every ambiguous method pair resolution.
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## Fix
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```julia
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visited = Set{Method}() # O(1) membership
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push!(visited, method2)
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workqueue = Method[method2]
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while !isempty(workqueue)
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current = pop!(workqueue)
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for k = 1:length(interferences)
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method3 = interferences[k]::Method
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method3 in visited && continue # O(1) hash lookup
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push!(visited, method3)
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push!(workqueue, method3)
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end
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end
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```
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Speedup: O(V²) → O(V) — ~250× at V=500 (62,500 → 500 checks).
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