uv author explains: env markers as decision diagrams, minimal equivalent DNF is computationally hard
charliermarsh · x · 2026-10-20
Charlie Marsh (author of uv/ruff) shares a internals detail: Python environment markers like pythonversion >= '3.11' or sysplatform == 'win32' are represented internally as decision diagrams, enabling efficient combination, equivalence checking, and satisfiability checks. But writing markers back to the lockfile requires converting back to Python marker syntax in DNF form — and finding the smallest equivalent DNF is computationally hard. A neat look at an obscure CS problem hiding inside package management.
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