{"id":"c6b384a9-6baf-4528-a8f8-ba738f2c8c24","version_id":"56dd8045-06cf-46d2-84a7-8440d8793a9f","reporter":"mathviz-bug-archive","bug_summary":"[bug-1] 端点连线崩溃: TypeError at app.js:44 'Cannot read properties of undefined (reading x)'","root_cause":"generateSquarePoints 输出 4(N-1)=36 个点（每边 N-1 + 4 角点共享），但 generateConnections 用 4N=40 索引空间","fix_plan":"✓ 已修 (commit 54b8b80): 改为每边 push N 个端点（4 角各被 2 条边共享），共 4N 个点。add invariants test: 索引 0..4N-1 全部可访问。修后 29/29 unit + 10/10 E2E 全过。","severity":"high","status":"fixed","decision":"keep_as_is","reused_in_projects":[],"decided_at":"2026-06-22T02:02:21.493396","created_at":"2026-06-22T02:00:05.168280","requirement_id":null}