Moves six clipped labels onto free connector segments and adds scripts/verify-geometry.py with tests, CI wiring, ADR 0005, and SKILL.md rule 6 so the defect cannot recur. Fixes #45.
40 lines
2.2 KiB
Markdown
40 lines
2.2 KiB
Markdown
# ADR 0005 — Label placement is verified geometrically, not by review
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**Status:** accepted (v2.3)
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## Context
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SKILL.md §6 rule 2 keeps an arrow label 6–10px clear of its own connector, and rule 5 keeps
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connectors from passing behind non-endpoint boxes. Neither rule constrains a label against a
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*node*. Because §5 fixes the paint order as background → zones → arrows → labels → nodes, a
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label mask that lands partly inside a node is covered by the node fill: the text renders as a
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fragment sitting on the node border.
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Nine shipped examples across two types (architecture, swimlane) had shipped this way. Every
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existing gate passed on all of them — `lint-skin.py` checks colors, fonts, and the accessible
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SVG contract; `self_check.py` checks DOM structure and the motion contract; neither reads
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coordinates. The defect is only visible when the file is rendered, so it survived review in
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three variants at a time.
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## Decision
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1. Label placement gets an explicit rule (SKILL.md §6 rule 6) rather than being left to the
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author's eye.
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2. The rule is enforced by `scripts/verify-geometry.py`, which parses `<rect>` coordinates and
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reports a mask that overlaps a node **declared later in the document**. Document order is
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the criterion, not overlap alone: a mask over an earlier-painted zone container stays on
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top and is legal, and a mask fully inside a node is a badge chip.
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3. The checker carries adversarial tests (`scripts/test-verify-geometry.py`) covering both
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polarities — a clipped mask must be reported, and the legal cases must not be.
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## Consequences
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- Geometric contracts in this repo are expressed as checkers with fixtures, in line with how
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the import extractors are verified. A rule that only lives in prose is a rule that ships
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broken examples.
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- The heuristics are shape-based (node ≥ 60×40, mask 20–120 × 8–14) and match the shipped
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templates. A future type with markedly different proportions may need the thresholds
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revisited — widen them in the checker, and add the case to the adversarial tests.
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- The checker does not evaluate the 6–10px connector gap from rule 2, which needs stroke
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geometry rather than rectangles. That rule remains a checklist item.
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